th 400

[tom robison]

what is the best to use, a short tail shaft or a long tail shaft?

 

[CTX-SLPR]

Short tail works better as far as driveline geometry but you can use a long tail if its what you got. No difference in strength really just a long tail shaft that can mess with the allignment of your U-joints.

 

[tom robison]

can you change the geometery with adjustable uper trailing arms?

 

[CTX-SLPR]

you can adjust the pinion angle with adjustable rear control arms but moving one will effect the other negatively. going with an aftermarket G-force www.crossmembers.com crossmember might address that better with a slightly relocated transmission mount pad allowing you to lower the rear of the transmission down closer to the level of the pinion. It will work just not the "perfered" tranny to use. There are plenty of issues with using any TH400 other than driveline geometry.

 

[tom robison]

what other issues are there?

 

[CTX-SLPR]

first and foremost is the fact that any transmission used on a Naturally aspirated engine uses engine vacuum to determine engine load. Because a forced induction engine will cross out of vacuum into booste the vacuum modulator on on the transmission won't know what to think. A solution to this is to use a mechanical modulator if you want to keep full automatic shifting or go to a full manual valvebody. The kickdown on the TH400 is controled by an electric switch on the accellerator pedal of cars that originally came with one while Lokar offers an electric kickdown switch that is cable operated and can be mouted out of the way. Do a search for TH400 in the transmission forum and see what you can find on the subject.

 

[tom robison]

why don't alot of people like the th400 in a street driven gn or t type?I know they rob some power but you can make it up somewere else.

 

[CTX-SLPR]

its not the power lost, its the loss of overdrive that makes it not desireable for the street.

 

[tom robison]

thanks for the info