TH350 rebuild tech
From Crankshaft Coalition Wiki
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| − | ==Overview== | + | ==T-350 Overview== |
| − | The GM Turbo Hydra-Matic 350 transmission (aka " | + | The GM Turbo Hydra-Matic 350 transmission (aka "T-350", "Turbo 350", THM350, etc.) was used between 1968-'86 in RWD and 4WD GM domestic vehicles. The TH350 was still produced many years beyond 1986 for export sales. It is a relatively rugged, compact transmission that lends itself to a wide variety of applications and modifications. |
==Basic rebuild information== | ==Basic rebuild information== | ||
{{Note1}} | {{Note1}} | ||
*This wiki is not intended to be a replacement for an ATSG or factory tech manual. First time builders will likely need a tech manual. Recommended is Ron Sessions' book, [http://www.amazon.com/Turbo-Hydra-Matic-350-Handbook-Sessions/dp/0895860511 '''''Turbo Hydra-Matic 350 Handbook'''''] in the HP book series. It has good pictures, a lot of good info, but has some outdated info. Outstanding value for the money. | *This wiki is not intended to be a replacement for an ATSG or factory tech manual. First time builders will likely need a tech manual. Recommended is Ron Sessions' book, [http://www.amazon.com/Turbo-Hydra-Matic-350-Handbook-Sessions/dp/0895860511 '''''Turbo Hydra-Matic 350 Handbook'''''] in the HP book series. It has good pictures, a lot of good info, but has some outdated info. Outstanding value for the money. | ||
| − | *This is not a step-by step tutorial. That said, the following should help give a better understanding of the | + | *This is not a step-by step tutorial. That said, the following should help give a better understanding of the T-350 and possibly help when a question arises. |
*The following page was inspired by an original Hotrodders forum thread by jakeshoe, titled [http://www.hotrodders.com/forum/th350-rebuild-tech-145361.html ''TH350 Rebuild Tech'']. | *The following page was inspired by an original Hotrodders forum thread by jakeshoe, titled [http://www.hotrodders.com/forum/th350-rebuild-tech-145361.html ''TH350 Rebuild Tech'']. | ||
| − | ==Variations of the | + | ==Variations of the T-350 family== |
| − | There is also a | + | There is also a T-350C and T-250C version that has a lockup torque converter (TCC). Look for the end of the input shaft to have a smooth polished end with O-ring on it, similar in appearance to the 200C/2004R and 700R4/pre-LSx 4L60E. The case has a "C" cast into it, and there will be an electrical plug adjacent to the shifter shaft on the driver side of the tranny. Same also holds true with the oil pump - "C" is cast into the pump cover and pump half. |
| − | Don't confuse the | + | Don't confuse the T-350C with a T-350 '''non'''-lockup tranny with a screwed-in electrical connector on the ''passenger'' side of the case. This is a pressure switch that was used ~1972-'73 for the Transmission Controlled Spark (TCS) system. This disabled the distributor vacuum advance in all gears except high gear, and is a single wire switch threaded into a pressure port near where the cooler lines are located. In the case of this switch, you can either leave it in place, unused- or remove it and plug the port. |
Hughes, TCI and Boss Hog make TH350C torque converters. | Hughes, TCI and Boss Hog make TH350C torque converters. | ||
| − | ==Rebuilding the | + | ==Rebuilding the T-350== |
===Bushings and thrust washers=== | ===Bushings and thrust washers=== | ||
| − | A | + | A T-350 is known to be rough on bushings. Bushings are critical in that they allow the rotating parts to ride true on center, and for the lube to make it to the rear of the trans. |
| − | Be prepared to replace almost ALL the bushings in a | + | Be prepared to replace almost ALL the bushings in a T-350. Might as well order a bushing kit, as well as a thrust washer kit. It is also recommended to get two additional sun gear bushings individually. |
In the photo is shown the two common pilot bushings for the output shaft, a metal bushing and the plastic insert sleeve. The plastic sleeve design is very durable, you will find professional builders have their own preference. | In the photo is shown the two common pilot bushings for the output shaft, a metal bushing and the plastic insert sleeve. The plastic sleeve design is very durable, you will find professional builders have their own preference. | ||
{| | {| | ||
| − | |[[File:T-350_bushings.jpg|thumb|300px|left| | + | |[[File:T-350_bushings.jpg|thumb|300px|left|T-350 bushings]] |
| − | |[[File:T-350_thrust_washers.jpg|thumb|300px|left| | + | |[[File:T-350_thrust_washers.jpg|thumb|300px|left|T-350 thrust washer kit]] |
|} | |} | ||
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While it may be true that removing the accumulator spring from the 1-2 servo will firm up the 1-2 shift, leaving the 1-2 accumulator spring out is not recommended. One reason is the accumulator protects the failure-prone intermediate sprag and another is the spring keeps the cover loaded against the snap ring. Photo shows accumulator cover, spring and piston (snap ring not shown). This is located on right side of transmission case. Check the bore in the case for scratches or other damage if the spring was found broken. | While it may be true that removing the accumulator spring from the 1-2 servo will firm up the 1-2 shift, leaving the 1-2 accumulator spring out is not recommended. One reason is the accumulator protects the failure-prone intermediate sprag and another is the spring keeps the cover loaded against the snap ring. Photo shows accumulator cover, spring and piston (snap ring not shown). This is located on right side of transmission case. Check the bore in the case for scratches or other damage if the spring was found broken. | ||
| − | [[File:T-350_acumilator01.jpg|thumb|300px|left| | + | [[File:T-350_acumilator01.jpg|thumb|300px|left|T-350 Accumulator cover, spring and piston with sealing rings]] <br style="clear:both"/> |
| − | Right side of | + | Right side of T-350 case. Pressure ports are circled. |
*Rear port (yellow) is main line pressure. You will see pressure here in all gears for most valve body configurations. Some race-only valve bodies may not have pressure at this port or the others | *Rear port (yellow) is main line pressure. You will see pressure here in all gears for most valve body configurations. Some race-only valve bodies may not have pressure at this port or the others | ||
*Middle port (red) is 2nd gear pressure | *Middle port (red) is 2nd gear pressure | ||
*Front port (blue) is third gear pressure | *Front port (blue) is third gear pressure | ||
| − | [[File:T-350_acumilator02.jpg|thumb|300px|left| | + | [[File:T-350_acumilator02.jpg|thumb|300px|left|T-350 pressure ports circled]] <br style="clear:both"/> |
=Transmission reassembly= | =Transmission reassembly= | ||
==Low-reverse piston install== | ==Low-reverse piston install== | ||
| − | The first item to go in the case will be the low/reverse apply piston. Its function is for oil to force it towards the front or | + | The first item to go in the case will be the low/reverse apply piston. Its function is for oil to force it towards the front or bell housing side of the trans, applying the low/reverse clutches. This allows reverse when applied simultaneously with the direct (high gear) clutches, and allows manual low gear when applied with the forward clutches. Manual low gear creates engine braking on deceleration. The low/reverse clutches do not apply in automatic range 1st gear. The low sprag (low roller clutch actually) causes first gear when only the forward clutches are applied. |
In the rare application that does not need reverse or low gear engine braking, the low piston and low clutches can be deleted and the feed holes in the case blocked. | In the rare application that does not need reverse or low gear engine braking, the low piston and low clutches can be deleted and the feed holes in the case blocked. | ||
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Install new seals on the low piston, these are square cut seals, not lip seals. | Install new seals on the low piston, these are square cut seals, not lip seals. | ||
| − | [[File:T-350_low_piston.jpg|thumb|300px|left| | + | [[File:T-350_low_piston.jpg|thumb|300px|left|T-350 low-reverse piston has three seals on it, creating two separate sections]] <br style="clear:both"/> |
Then push it into the rear of the case evenly by hand, aligning it properly so it will seat (there is a "tang"). Look at the park pawl notch to help index it. | Then push it into the rear of the case evenly by hand, aligning it properly so it will seat (there is a "tang"). Look at the park pawl notch to help index it. | ||
| − | [[File:T-350caselowpiston.jpg|thumb|300px|left| | + | [[File:T-350caselowpiston.jpg|thumb|300px|left|T-350 low-reverse piston installed into case]] <br style="clear:both"/> |
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Next you install the output shaft. | Next you install the output shaft. | ||
| − | [[File:T-350_output_bearing.jpg|thumb|300px|left| | + | [[File:T-350_output_bearing.jpg|thumb|300px|left|T-350 output shaft with bearing that fits between case and ring gear]] <br style="clear:both"/> |
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Now you can install the low/reverse clutches, beginning with a steel, then a friction, alternating, ending with a friction. | Now you can install the low/reverse clutches, beginning with a steel, then a friction, alternating, ending with a friction. | ||
| − | [[File:T-350_low_clutch_install.jpg|thumb|300px|left| | + | [[File:T-350_low_clutch_install.jpg|thumb|300px|left|T-350 low-reverse frictions and steels installed with planetary and output shaft]] <br style="clear:both"/> |
{{Note1}}If you have a light duty core with low count low pack, unless it is a transbrake application or will be manually shifted into low for engine braking often, fewer clutches is OK. In some cases where you are after every last bit of ET, using fewer clutches can cause less frictional loss in 2nd and high gear. "Turbulator" steel plates from a 4L60E will also help and are a direct drop-in. | {{Note1}}If you have a light duty core with low count low pack, unless it is a transbrake application or will be manually shifted into low for engine braking often, fewer clutches is OK. In some cases where you are after every last bit of ET, using fewer clutches can cause less frictional loss in 2nd and high gear. "Turbulator" steel plates from a 4L60E will also help and are a direct drop-in. | ||
| − | There are Alto red frictions in this unit, however a stock tan clutch ( like Borg Warner brand) is more than adequate for even very high HP cars. A Hi-Energy Borg from a 4L60E is also a good choice. | + | There are Alto red frictions in this unit, however a stock tan clutch ( like Borg Warner brand) is more than adequate for even very high HP cars. A Hi-Energy Borg Warner friction from a 4L60E is also a good choice. |
Once the low clutches are installed, you can install the anti-clunk spring (or case-saver). Hold in place with assembly gel or vaseline and then install the low-reverse support. | Once the low clutches are installed, you can install the anti-clunk spring (or case-saver). Hold in place with assembly gel or vaseline and then install the low-reverse support. | ||
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[[File:T-350_anti-rattle_spring.jpg|thumb|300px|left|Anti rattle (clunk) spring shown in correct location; use assembly grease to hold in place]] <br style="clear:both"/> | [[File:T-350_anti-rattle_spring.jpg|thumb|300px|left|Anti rattle (clunk) spring shown in correct location; use assembly grease to hold in place]] <br style="clear:both"/> | ||
| − | Be sure the low sprag inner race is not brinelled or has any unusual wear. | + | Be sure the low sprag inner race is not brinelled or has any unusual wear. A center support from a 1987-present 700R4 or 4L60E (including the aftermarket case saver with a bolt-on outer plate held with torx head bolts) can be used in place of the stock center support since the roller clutch is wider. |
[[File:T-350_center_suport_sprag.jpg|thumb|300px|left|Photo shows center support with sprag (roller clutch) and inner race]] <br style="clear:both"/> | [[File:T-350_center_suport_sprag.jpg|thumb|300px|left|Photo shows center support with sprag (roller clutch) and inner race]] <br style="clear:both"/> | ||
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[[File:T-350_ring_gear_with_washer.jpg|thumb|300px|left|Front ring gear with 3-tang thrust washer in place installed into case on front planet]] <br style="clear:both"/> | [[File:T-350_ring_gear_with_washer.jpg|thumb|300px|left|Front ring gear with 3-tang thrust washer in place installed into case on front planet]] <br style="clear:both"/> | ||
| − | ==Direct drum assembly== | + | ==T-350 Direct drum assembly== |
For racing and heavy towing use, you will want to machine the direct clutch piston down approximately 0.160" to allow for one extra friction and steel plate for a total of 5 frictions, and 5 steels in the directs. This can be accomplished on a brake lathe. | For racing and heavy towing use, you will want to machine the direct clutch piston down approximately 0.160" to allow for one extra friction and steel plate for a total of 5 frictions, and 5 steels in the directs. This can be accomplished on a brake lathe. | ||
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If the piston is too low, the bottom flat steel plate can drop below the grooves in the drum and bind up the piston. You can leave out center cushion seal if dual feed is used. | If the piston is too low, the bottom flat steel plate can drop below the grooves in the drum and bind up the piston. You can leave out center cushion seal if dual feed is used. | ||
| − | [[File:T-350_direct_piston.jpg|thumb|300px|left| | + | [[File:T-350_direct_piston.jpg|thumb|300px|left|T-350 direct clutch drum pistons, piston on left cut for 5 friction use]] <br style="clear:both"/> |
| − | Heavy duty applications should also get a heat treated intermediate sprag race. The heat treatment makes the race less brittle. A heat treated intermediate sprag race is darker colored than a stock part. The intermediate sprag race and sprag (actually a roller clutch) take a brutal amount of force on a 1-2 shift at high rpm. Even more so with harsher shift calibrations. It is the single weakest part of a TH350. This is not to say a TH350 is not tough; they can reliably handle power in the 600 HP or lb/ft range if properly assembled using the right parts. | + | Heavy duty applications should also get a heat treated intermediate sprag race. The heat treatment makes the race less brittle. A heat treated intermediate sprag race is darker colored than a stock part. The T-350 intermediate sprag race and sprag (actually a roller clutch) take a brutal amount of force on a 1-2 shift at high rpm. Even more so with harsher shift calibrations. It is the single weakest part of a TH350. This is not to say a TH350 is not tough; they can reliably handle power in the 600 HP or lb/ft range if properly assembled using the right parts. |
[[file:TH350intspragraces.jpg]] | [[file:TH350intspragraces.jpg]] | ||
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Several companies offer an even heavier duty direct drum/sprag assembly. It uses a 36 element sprag (similar to what is used in the TH400) and a machined drum; it will withstand more torque than a stock unit or one with just a hardened race. These units can cost $300.00 or more. | Several companies offer an even heavier duty direct drum/sprag assembly. It uses a 36 element sprag (similar to what is used in the TH400) and a machined drum; it will withstand more torque than a stock unit or one with just a hardened race. These units can cost $300.00 or more. | ||
| − | [[File:T-350_HD_drum_sprag.jpg|thumb|300px|left| | + | [[File:T-350_HD_drum_sprag.jpg|thumb|300px|left|T-350 direct clutch drum with 36 element sprag]] <br style="clear:both"/> |
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The parts go on the direct drum. | The parts go on the direct drum. | ||
| − | [[File:T-350 drum sprag race.jpg|thumb|300px|left| | + | [[File:T-350 drum sprag race.jpg|thumb|300px|left|T-350 direct clutch drum with sprag, race, retainer]] <br style="clear:both"/> |
Assembled direct drum sprag and race with retainer. | Assembled direct drum sprag and race with retainer. | ||
| − | [[File:T-350_drum_sprag_assembled.jpg|thumb|300px|left| | + | [[File:T-350_drum_sprag_assembled.jpg|thumb|300px|left|T-350 direct clutch drum with assembled sprag, race, retainer]] <br style="clear:both"/> |
| − | The direct drum should use a wider bushing even on stock rebuilds. Stock is 0.500" a wider 0.750" is available in some bushing kits. Most bushing kits include the wide one. There is a lot of load on this bushing, and it should ALWAYS be replaced on overhaul. | + | The T-350 direct drum should use a wider bushing even on stock rebuilds. Stock is 0.500" a wider 0.750" is available in some bushing kits. Most bushing kits include the wide one. There is a lot of load on this bushing, and it should ALWAYS be replaced on overhaul. |
| − | [[File:TH350directbushings1.jpg|thumb|300px|left|The direct drum should use a wider bushing even on stock rebuilds]] <br style="clear:both"/> | + | [[File:TH350directbushings1.jpg|thumb|300px|left|The T-350 direct drum should use a wider bushing even on stock rebuilds]] <br style="clear:both"/> |
Also check the inside bore of the drum for wear from the sealing rings. A small amount of wear can be honed out. Visual shiny spots with no detectable wear are acceptable. | Also check the inside bore of the drum for wear from the sealing rings. A small amount of wear can be honed out. Visual shiny spots with no detectable wear are acceptable. | ||
| − | [[File:T-350_direct_drum_bushing.jpg|thumb|300px|left|Direct drum with wide bushing, piston, springs and retainer installed]] <br style="clear:both"/> | + | [[File:T-350_direct_drum_bushing.jpg|thumb|300px|left|T-350 Direct drum with wide bushing, piston, springs and retainer installed]] <br style="clear:both"/> |
Next you will install the direct piston lip seals, and install the piston in the drum. Take note of the orientation of the seals, the lip will face towards the "oil" side of the piston, not the clutch side. | Next you will install the direct piston lip seals, and install the piston in the drum. Take note of the orientation of the seals, the lip will face towards the "oil" side of the piston, not the clutch side. | ||
| − | Below is a high performance | + | Below is a high performance T-350 piston for a drum without a center seal that would separate the two halves of the direct piston. |
| − | [[File:TH350directpistonseals1.jpg|thumb|300px|left|Direct piston with lip seals installed]] <br style="clear:both"/> | + | [[File:TH350directpistonseals1.jpg|thumb|300px|left|T-350 Direct piston with lip seals installed]] <br style="clear:both"/> |
==Dual feeding== | ==Dual feeding== | ||
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[[File:T-350_fwd_drum.jpg|thumb|300px|left|Check forward drum for wear.]]<br style="clear:both"/> | [[File:T-350_fwd_drum.jpg|thumb|300px|left|Check forward drum for wear.]]<br style="clear:both"/> | ||
| − | ===Pump assembly=== | + | ===T-350 Pump assembly=== |
| − | '''Notice''' the scraped and split low reverse friction in the intermediate piston cavity. This slightly tightens the intermediate clutch clearance to achieve cleaner 1-2 shift. | + | '''Notice''' the scraped and split T-350 low reverse friction in the intermediate piston cavity. This slightly tightens the intermediate clutch clearance to achieve cleaner 1-2 shift. |
| − | [[File:T-350_intmed_piston_spacer.jpg|thumb|300px|left|Scraped and split low reverse friction in the intermediate piston cavity]]<br style="clear:both"/> | + | [[File:T-350_intmed_piston_spacer.jpg|thumb|300px|left|Scraped and split T-350 low reverse friction in the intermediate piston cavity]]<br style="clear:both"/> |
Intermediate piston installed. | Intermediate piston installed. | ||
| − | [[File:T-350_pump_n_piston.jpg|thumb|300px|left| | + | [[File:T-350_pump_n_piston.jpg|thumb|300px|left|T-350 pump with intermediate piston installed]]<br style="clear:both"/> |
| − | Sealing rings on the pump stator. Remove the second ring from the bottom if dual feeding. | + | Sealing rings on the T-350 pump stator. Remove the second ring from the bottom if dual feeding. |
[[File:T-350_stator_rings.jpg|thumb|300px|left|Sealing rings on pump]] <br style="clear:both"/> | [[File:T-350_stator_rings.jpg|thumb|300px|left|Sealing rings on pump]] <br style="clear:both"/> | ||
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Pump gear install. Note the orientation of the tangs on the inner gear. They are offset. They should face away from the seal. Incorrect installation will result in pump failure and converter damage. | Pump gear install. Note the orientation of the tangs on the inner gear. They are offset. They should face away from the seal. Incorrect installation will result in pump failure and converter damage. | ||
| − | [[File:T-350_pump_half.jpg|thumb|300px|left|Notice inner pump gear tangs, they must be '''up''' as seen here]] <br style="clear:both"/> | + | [[File:T-350_pump_half.jpg|thumb|300px|left|Notice the T-350 inner pump gear tangs, they must be '''up''' as seen here]] <br style="clear:both"/> |
Notice the dowel pins threaded into the case, you use these and the case to align the pump halves. | Notice the dowel pins threaded into the case, you use these and the case to align the pump halves. | ||
| − | [[File:T-350_pump_alignment.jpg|thumb|300px|left|One method to align the pump halves shown]] <br style="clear:both"/> | + | [[File:T-350_pump_alignment.jpg|thumb|300px|left|One method to align the T-350 pump halves shown]] <br style="clear:both"/> |
| − | This is an example of to air check the forward and direct drum. After everything is assembled, I place the drums on the pump (above a hole in the bench) with all sealing rings in place, thrust washers or bearings. | + | This is an example of to air check the T-350 forward and direct drum. After everything is assembled, I place the T-350 drums on the pump (above a hole in the bench) with all sealing rings in place, thrust washers or bearings. |
Use a rubber tipped air nozzle to apply air to the passages around the pump circumference. As you apply air to the correct passages, you will see and hear the drums apply the clutches. Be sure there are no leaks from the lip seals. There will usually be some minor leakage at the sealing rings. Iron rings air check better than teflon on the bench. | Use a rubber tipped air nozzle to apply air to the passages around the pump circumference. As you apply air to the correct passages, you will see and hear the drums apply the clutches. Be sure there are no leaks from the lip seals. There will usually be some minor leakage at the sealing rings. Iron rings air check better than teflon on the bench. | ||
| − | [[File:T-350_air_check_pump.jpg|thumb|300px|left|One method to air check clutch drums in the pump shown. Refer to build manual for locations]] <br style="clear:both"/> | + | [[File:T-350_air_check_pump.jpg|thumb|300px|left|One method to air check T-350 clutch drums in the pump shown. Refer to build manual for locations]] <br style="clear:both"/> |
| − | Drums installed in the transmission case. Ready for intermediate pressure plate install. Ensure the lugs of the direct drum are engaged with the sun shell. They should be slightly below the top edge of the sun shell. If you do not get complete engagement, the input shaft will not turn when you install the pump and begin to tighten it. You can also see the braking band installed. | + | T-350 Drums installed in the transmission case. Ready for intermediate pressure plate install. Ensure the lugs of the direct drum are engaged with the sun shell. They should be slightly below the top edge of the sun shell. If you do not get complete engagement, the input shaft will not turn when you install the pump and begin to tighten it. You can also see the braking band installed. |
| − | [[File:T-350_coast_band01.jpg|thumb|300px|left|Both clutch drums installed with braking band shown]] <br style="clear:both"/> | + | [[File:T-350_coast_band01.jpg|thumb|300px|left|Both T-350 clutch drums installed with braking band shown]] <br style="clear:both"/> |
===Braking band=== | ===Braking band=== | ||
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[[File:T-350_HD__braking_band.jpg|thumb|300px|left|Heavy duty brake band should have weld reinforced struts]]<br style="clear:both"/> | [[File:T-350_HD__braking_band.jpg|thumb|300px|left|Heavy duty brake band should have weld reinforced struts]]<br style="clear:both"/> | ||
| − | =Intermediate clutch= | + | =T-350 Intermediate clutch= |
6 cylinder applications use an intermediate piston measuring 1.175"-1.185" thick. The 6 cylinder uses two frictions. | 6 cylinder applications use an intermediate piston measuring 1.175"-1.185" thick. The 6 cylinder uses two frictions. | ||
| − | The V8 intermediate uses three frictions. The piston is about 0.990" thick. | + | The V8 T-350 intermediate uses three frictions. The T-350 piston is about 0.990" thick. |
The wavy cushion plate should be used. | The wavy cushion plate should be used. | ||
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There are two types of intermediate return spring/retainers. With the early type you had to manually place the loose springs onto the piston's spring locator bosses,then the retainer went over that. The later retainer has the springs attached to their respective retainers (the bosses are not used). So if the intermediate piston is smooth, use the retainer with the springs attached to it. The late retainers will work in a transmission that originally used the early type retainer, but not vice versa. | There are two types of intermediate return spring/retainers. With the early type you had to manually place the loose springs onto the piston's spring locator bosses,then the retainer went over that. The later retainer has the springs attached to their respective retainers (the bosses are not used). So if the intermediate piston is smooth, use the retainer with the springs attached to it. The late retainers will work in a transmission that originally used the early type retainer, but not vice versa. | ||
| − | ==Intermediate clutch clearance== | + | ==T-350 Intermediate clutch clearance== |
| − | After the pump is set into place to test end play clearance, you can also check the clutch clearance on the intermediate clutch pack. Clearance of 0.050" to 0.070" will work well. There are thicker intermediate steel plates available if need to tighten up the clutch pack clearance. Intermediate steels | + | After the pump is set into place to test end play clearance, you can also check the clutch clearance on the intermediate clutch pack. Clearance of 0.050" to 0.070" will work well. There are thicker intermediate steel plates available if need to tighten up the clutch pack clearance. T-350 Intermediate steels are available in 0.068", 0.078" and 0.089" thicknesses, some manufacturers may use slightly different thicknesses than these. |
| − | Also, a scraped low-reverse friction can be used under the intermediate | + | Also, a T-350 scraped low-reverse friction can be used under the intermediate piston if need be. A scraped T-350 friction will measure about 0.032". |
| − | [[File:T-350_intermed_clearance_ck.jpg|thumb|300px|left| | + | [[File:T-350_intermed_clearance_ck.jpg|thumb|300px|left|T-350 intermediate clutch pack clearance can be checked through this hole]] <br style="clear:both"/> |
=Valve body= | =Valve body= | ||
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| − | This gasket on a | + | This gasket on a T-350 sits against the valve body. Notice the open line in the gasket that will parallel the support plate that bolts on at front of the valve body. |
[[file:T-350_v-body_gasket02.jpg|frame|none|Notice the open line in the gasket, this gasket installs against valve body, not the case]] | [[file:T-350_v-body_gasket02.jpg|frame|none|Notice the open line in the gasket, this gasket installs against valve body, not the case]] | ||
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Below is a picture of the feed holes. These regulate the amount of fluid, or how fast it can apply the clutches. Drilling them bigger allows a faster apply. However, bigger is not always better. | Below is a picture of the feed holes. These regulate the amount of fluid, or how fast it can apply the clutches. Drilling them bigger allows a faster apply. However, bigger is not always better. | ||
| − | [[file: | + | [[file:T-350feedholes.jpg]] |
Remember that as the load increases on the trans, so does the pressure. The increase in pressure will cause the fluid to move faster and shifts to be firmer. If you drill the holes ''too'' big the shifts become too harsh at light throttle openings. This causes undue wear on the internal transmission parts, rear differential and axles, drive line and u-joints. | Remember that as the load increases on the trans, so does the pressure. The increase in pressure will cause the fluid to move faster and shifts to be firmer. If you drill the holes ''too'' big the shifts become too harsh at light throttle openings. This causes undue wear on the internal transmission parts, rear differential and axles, drive line and u-joints. | ||
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Coan reverse manual valve body. Notice the machining of passages. Please note the DIY cannot just mill the valve body as valves have also been changed in the valve body. | Coan reverse manual valve body. Notice the machining of passages. Please note the DIY cannot just mill the valve body as valves have also been changed in the valve body. | ||
| − | [[file: | + | [[file:T-350reverseVB.jpg]] |
=Governor= | =Governor= | ||
| − | Image below of an OEM | + | Image below of an OEM T-350 governor and cover. |
[[file:T-350_governor.jpg|thumb|left|300px|Note the direction of the plastic drive gear teeth. If the plastic gear breaks or wears out, there will be no upshifts since the governor is not rotating.]]<br style="clear:both"/> | [[file:T-350_governor.jpg|thumb|left|300px|Note the direction of the plastic drive gear teeth. If the plastic gear breaks or wears out, there will be no upshifts since the governor is not rotating.]]<br style="clear:both"/> | ||
| Line 351: | Line 351: | ||
=Filter= | =Filter= | ||
| − | Brass screened filter allows for more flow. Avoid the cloth looking material filters for the | + | Brass screened filter allows for more flow. Avoid the cloth looking material filters for the T-350 |
| − | [[file: | + | [[file:T-350HPfilter.jpg]] |
=Vacuum modulator= | =Vacuum modulator= | ||
| Line 391: | Line 391: | ||
*Intermediate Band Adjust Nut- 15 ft/lb | *Intermediate Band Adjust Nut- 15 ft/lb | ||
| − | = | + | =T-350 dimensions and tailshaft housing (or ''extension'' housing) lengths= |
[[File:TH350 dimensions.jpg|thumb|left|400px|]]<br style="clear:both"/> | [[File:TH350 dimensions.jpg|thumb|left|400px|]]<br style="clear:both"/> | ||
| − | You will find the | + | You will find the T-350 with 6", 9" and 12" tail housings. |
There is also two 4WD output shaft lengths, the shortest and more common is seen below. A longer 4x4 output shaft was used for around 1.5 years. It is a 2WD shaft of 6 inch length that is cut off about 1.250 inches. Used on 208 transfer case with adapter. | There is also two 4WD output shaft lengths, the shortest and more common is seen below. A longer 4x4 output shaft was used for around 1.5 years. It is a 2WD shaft of 6 inch length that is cut off about 1.250 inches. Used on 208 transfer case with adapter. | ||
| Line 402: | Line 402: | ||
=Gear ratios= | =Gear ratios= | ||
| − | Ratios of the | + | Ratios of the T-350 were consistent throughout its production: |
*First gear- 2.52:1 | *First gear- 2.52:1 | ||
*Second gear- 1.52:1 | *Second gear- 1.52:1 | ||
*Third gear- 1.00:1 | *Third gear- 1.00:1 | ||
| − | *Reverse- 1.93:1 | + | *Reverse- 1.93:1 |
=Aftermarket parts= | =Aftermarket parts= | ||
| Line 413: | Line 413: | ||
=Reference material= | =Reference material= | ||
| − | [[File:Sessions- ATSG-Haynes manuals.jpg|thumb|600px|left|Left to right: [http://www.amazon.com/Turbo-Hydra-Matic-350-Handbook-Sessions/dp/0895860511 Turbo Hydra-Matic 350 Handbook] by Ron Sessions; [http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=786 ATSG manual] p/n 44400; Haynes [http://www.amazon.com/gp/product/1563924234/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=0895860511&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0J4A1QHT1Y8B032P3Z6P GM Automatic Transmission Overhaul] manual, p/n 10360.]] <br | + | [[File:Sessions- ATSG-Haynes manuals.jpg|thumb|600px|left|Left to right: [http://www.amazon.com/Turbo-Hydra-Matic-350-Handbook-Sessions/dp/0895860511 Turbo Hydra-Matic 350 Handbook] by Ron Sessions; [http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=786 ATSG manual] p/n 44400; Haynes [http://www.amazon.com/gp/product/1563924234/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=0895860511&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0J4A1QHT1Y8B032P3Z6P GM Automatic Transmission Overhaul] manual, p/n 10360.]] <br> |
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[[Category:GM]] | [[Category:GM]] | ||
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