Transmission identification

by: Alittle1, Cobalt327, Crashfarmer, Crosley, Jon, M&M CUSTOM, Mmerlinn, Tomic
(Click here to edit this page anonymously, or register a username to be credited for your work.)

You can edit this article right now.

Just click the "edit" tab at the top of this page, or click one of the [edit] links to the right of an article section.

For more info, see Help:Editing pages.

Preamble

The purpose and function of this page is to acquaint people with the identification of popular North American made transmissions based on pan shape, case outline, and OEM numbering. This page also offers overall dimension, gear ratios and number of gears available in each transmission, and originating year, make and model.

GM transmissions

Automatic

A dual pattern bellhousing bolt pattern was used on a couple different GM automatics.

Universal GM bellhousing bolt pattern

TH350

The GM Turbo Hydra-Matic 350 transmission (aka "350", "TH350", "Turbo 350", etc.) was used between 1968-'86 in RWD and 4WD GM vehicles. It is a relatively rugged, compact transmission that lends itself to a wide variety of applications and modifications.

TH350 transmission ID

ID stamped into governor cover

TH350 dimensions and tailshaft (extension housing) lengths

You will find the TH350 with 6", 9" and 12" tail housings. There is also a 4WD output, shown below:

TH350C

There was also a TH350C version that has a lockup torque converter (TCC). 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. Not to be confused with a TH350 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. There have been reports of some TH350 trannys having a temp sender in this area as well.

TH250C

The TH250 looks almost identical to the TH350 externally- same size, same oil pan. Unlike the TH350, it has a band adjuster stud and lock nut on the passenger side of the case near the cooler lines. Be careful to not be fooled into thinking a TH250 is a TH350.

General information

Transmission identification by pan shape with gear ratios.

Image Number		Transmission(s)		Pan Bolts		1st Gear		2nd Gear		3rd Gear		4th Gear		Reverse
1		Aluminum Powerglide		14		1.76/1.82		1.00		-		-		1.76/1.82
2		TH200 (Metric), TH200C (Metric)		11		2.54		1.57		1.00		-		2.06
3		TH250, TH250C, TH350, TH350C, TH375B		13		2.52		1.52		1.00		-		1.94
4		TH375C, TH400, TH475, 3L80, 3L80HD		13		2.48		1.48		1.00		-		2.07
5		TH200-4R		16		2.54		1.57		1.00		0.67		2.06
6		TH700-R4, 4L60, 4L60E		16		3.06		1.62		1.00		0.70		2.29
7		4L80E		17		2.48		1.48		1.00		0.75		2.07

NOTE: An aluminum Powerglide also exists with an 18" extension housing.

TH250, TH250C, TH350, TH350C, TH375B transmissions

Identifying transmissions in the TH350 family.

Transmission		Type		Wire Plug		Band Adjusting Screw		Tail Housing
TH250		Non-lockup		None		Yes		6"
TH250C		Lockup		Driver Side		Yes		6" or 9"
TH350		Non-lockup		None		None		None, 6", or 9"
TH350C		Lockup		Driver side		None		None, 6", or 9"
TH375B		Non-lockup		None		None		12"

NOTE 1: Any of these may also have a switch on the passenger side near the TV cable.

NOTE 2: ALL V8 style Lockup transmissions have an input shaft with a polished tip and rubber O ring at the front end of this shaft.

List of vehicles that used the TH350 as original equipment:

The TH350 was used in some Y- and F-body cars in 1968, then across the board from 1969-‘80. From ’81-’86 the TH350C was available.

1969-'84 Buick, Chevrolet, Olds and Pontiac full-size cars

1969-'81 Buick, Chevrolet, Olds and Pontiac A-body, G-body and F-body cars (some F-body in '68)

1973-'79 Buick, Chevrolet, Olds and Pontiac X-body cars

1969-'78 Riviera

1968-'82 Corvette

1975-'80 Buick, Chevrolet, Olds and Pontiac H-body cars (Vega, Monza, Skyhawk, etc.)

1981-'82 Cadillac Fleetwood and Deville (CBC-350 and TH350C versions)

1973-'85 Chevy and GMC 2WD and 4WD pickups, Blazers, G-10, G-20 vans and Suburbans

TH200, TH2004R transmissions

Identifying transmissions in the TH200 family

Photo of a multi-pattern bell housing of a TH2004R

Rear view of a 2004R transmission with BOP design bell housing bolt pattern. Notice the valley between the top two bolt holes.

Photo of a Chevrolet bell housing bolt pattern. Notice the peak between the top two bolt holes on the bell housing.

TH700R4, 4L60 transmissions

Identifying transmissions in the TH700R4 family

TH700R4

Manual transmissions

General Information

Bell housing bolt pattern and measurements

Muncie M20, M21, M22 transmissions

Identifying Muncie M20 series transmissions.

The external differences between the three Muncie 4 speed transmissions can be deceiving. If the cover is removed, the pitch of the gears can be seen.

Link to a Muncie page showing gear ratio, spline counts, exploded view, parts list, etc.

Muncie ratios from D&L Transmissions.

Saginaw transmissions

Saginaw 4-speed transmission

Cast iron case

3 shift levers on side cover

Saginaw 4-speed Gear Ratios

Input		1st Gear		2nd Gear		3rd Gear		4th Gear		Notes
No grooves		2.84		2.01		1.34		1.00
1 groove		2.54		1.80		1.44		1.00		Common
1 groove		2.54		1.80		1.32		1.00		Rare
2 grooves		3.11		2.20		1.47		1.00
3 grooves		3.50		2.46		1.65		1.00

Ford Transmissions

Automatic

General information

Ford transmission ID

Gear Ratios of Popular Ford Automatic Transmissions

Transmission		1st Gear		2nd Gear		3rd Gear		4th Gear
C4/C5/C6		2.46		1.46		1.00		-
AOD/AODE		2.40		1.47		1.00		0.67
4R70W		2.84		1.55		1.00		0.70
E4OD/4R100		2.71		1.54		1.00		0.71

C3/C4/C5/C6/AOD series comparison

3-speed identification

Transmission(s)		Pan Bolts
C3		13
C4, C5		11
C6		17
FX Cruiso, MX Cruiso, FMX, CW		14

4-speed identification

Transmission(s)		Pan Bolts
A4LD, 4R44E, 4R55E		18
AOD, AODE, 4R70W		14
E4OD, 4R100		20

Ford-o-matic S3

The Cruise-O-Matic

Introduced in 1951, the Cruise-O-Matic series of three-speed automatics (which includes the FMX) was used in Ford, Lincoln and Mercury passenger cars until 1979, and in light trucks from 1968 through 1979.

They came in three configurations:

1. The small case (from 1951 to 1966).
2. The medium case (from 1955 to 1968).
3. The FMX (from 1967 to 1979).

• Early Cruise-O-Matics had a filler tube that attached to the transmission pan.
• FMX transmissions filler tube slid into the main case.

The Cruise-O-Matic/FMX transmissions are easily identified by their design, which incorporates a cast-iron main case (unlike all other Ford three-speed automatic offerings) with separate aluminum bellhousings and extension housings bolted to it. The Cruise-O-Matic should be avoided in performance applications as very little is available in the way of aftermarket performance parts other than shift kits. The Cruise-O-Matic were also offered with all three bolt-common V8-pattern bellhousings.

C4/C5

General information

• Years
  • C4: 1964-1982
  • C5: 1982-1986
• Bell housing: Aluminum
  • Case fill: Attaches to case with 7 pump bolts
  • Pan fill: Attaches to case with 5 bolts around outside of pump
• Case: Aluminum; 11 pan bolts; 2 adjusting screws; 2 servos; Modulator (Except PEG-A build code)
  • Case fill: Dipstick tube in case
  • Pan fill: Dipstick tube in pan
• Extension housing (2wd, Divorced 4x4): Aluminum; 6 bolts to case
• Adapter housing (Married 4x4): 6 bolts to case
  • C4: Cast iron
  • C5: Aluminum
• Front oil pump: 7 bolts to case
• Input shaft
  • 24x24 spline (1964-1969)
  • 26x26 spline (1970 only)
  • 26x24 spline (1971-1986)

C6

General Information

• Years: 1966-1996
• Bell housing: Integral
  • Big block (351M, 460, etc): 7-11/16" top bolt centers, No cutout on bottom
  • Diesel (426): 7-11/16" top bolt centers; Cutout on bottom
  • FE block (330/360/390): Round with starter at about 9:00
  • Lincoln (460): 5-3/4" top bolt centers; Pointed top
  • Lincoln (462): 5-1/4" top bolt centers; Pointed top
  • Small block (302, 351W, etc): 5-1/8" top bolt centers
• Case: Aluminum; 11 pan bolts; 1 adjusting screw; 1 servo; Modulator
• Extension housing (2WD, Divorced 4x4): 6 bolts to case
  • Aluminum
    • 7": Bearing; 0, 1, or 2 threaded bosses; With or without speedometer hole
    • 13-7/8": Bushing; With or without damper provision
    • 18": Bushing
  • Cast Iron
    • 5-3/8": Bearing; Bolt-on cast iron speedometer housing
    • 13-3/4": Bushing;
    • 17-1/4": Bushing; Mount near case or near speedometer hole; With or without damper provision
• Adapter housing (Married 4x4): 6 bolts to case
  • Aluminum
    • 5-3/4": 0, 1, or 2 threaded bosses; 1 or 2 transfer case cutouts
    • 8-3/4"
  • Cast iron
    • 5-3/4": 1 threaded boss; 1 or 2 transfer case cutouts
    • 8-3/4"
• Front oil pump: 7 bolts to case
• Input shaft
  • 31x31 splines (1966-1971)
  • 31x30 splines (1972-1996)

Manual

Mopar transmissions

Automatic

A518/A618 (Left), A727 (Center), A500 (Right)

Manual

AMC/Rambler transmissions

Antti-Ville Nauha (Pori, Finland) AMC CLUB FINLAND (AMCCF) long ago compiled this excellent guide to identifying AMC and Rambler transmissions.

http://www.charlietranny.com/AMC.htm

Other transmissions

Automatic

Manual

Common manual transmission identification

Also see

• Crankshaft Coalition page Identifying transmissions.

Resources

1. GM Automatic Transmission Identification and Information -- Very helpful identification guide with identification by pan and transmission dimensions.
2. Borg Warner Second Design ST-10 4-Speed Info -- Codes, applications; a very informative page.
3. Borg Warner Second Design ST-10 4-Speed Info from Pontiac Power.