Editing TH400 rebuild tech (section)
Jump to:
navigation
,
search
===Boost valve modification=== (Full manual shift only) Modification of the boost valve to have static line pressure and vacuum modulator replaced with aluminum plug. This modification of the boost valve avoids the run away high line pressure in reverse. Grind a flat spot on the large spool valve land with arrow pointed at it. It is not fussy, 1/4" to 3/8" wide is fine. [[file:400boost01.jpg]] Hole location in case to plug. This is shown with the pump removed from the case. This passage must be plugged if boost valve land is ground with flat spot. [[file:400boost02.jpg]] Method #2 to plug passage in case: You can remove the valve body and plug the hole shown in photo if pump removal is not going to happen. Perform this method or the method posted above. Both are not needed. You can slip a 1/4" check ball into the square hole and push it into the round passage at the base of this square hole. [[file:Block_rev_hole.jpg]] After the boost valve modification, you can install an aluminum plug that blocks the modulator valve in place. The original bolt and bracket from the vacuum modulator holds the aluminum plug in place. [[file:T-400_modulator_plug.jpg]]
|
Editing help
(opens in new window)
Personal tools
Log in / create account
Namespaces
Page
Discussion
Variants
Views
Read
Edit
View history
Actions
Search
Navigation
Main Page
Recent changes
Random page
Help
All articles
Start a new article
Hotrodders forum
Categories
Best articles
Body and exterior
Brakes
Cooling
Electrical
Engine
Fasteners
Frame
Garage and shop
General hotrodding
Identification and decoding
Interior
Rearend
Safety
Steering
Suspension
Tires
Tools
Transmission
Troubleshooting
Wheels
Toolbox
What links here
Related changes
Special pages
Terms of Use
Copyright
Privacy Policy
Your Privacy Choices
Manage Consent