Th400???

I've got a TH400 out of a '83 chevy diesel, is this the same "desireable" trans as the car TH400's or what??? thanks-

 

Should be heavier duty than the standard car TH400 and not really necessary for just a street driver. Somebody needing a TH400 for a higher perfomance application could use it.

 

Should be the same except for the vacuum modulator circuit. Diesels dont have manifold vacuum. Might need a different valve body.

 

Should be the T-475. Truck version with an extra clutch pack and heavy duty internals. Like an old QQ code from the musclecar days.

It will need a new valve body tho. Try to find one out of a full size buick with a 455, as those have the largest internal passages of any GM 400 valve body and will give you full downshifts into 1st instead of 2nd.

*some* [not all] GM diesel's had vacuum pumps where the distributor goes on a gas burner, so there's a chance your tranny os a vac model... But maybe not. At any rate, the diesel setup is for low rpm opperation.

It has the potential to be the foundation for one helluva strong street tranny.

 

Both the 82 6.2l and 84 6.2L trucks and all of our 6.5L trucks we had ran factory vacuum pumps, and honestly, I'm not aware of a 6.2/6.5 without one, so it should be a vacuum mod. trans. The torque convertor should be uber-low rpm diesel specific though.

 

Check the rear and see if it has that bolt in yoke, if it does you'll need a custom yoke or change the output shaft.

 

I have used an old style TH400 with a short tail shaft in our race car ,and never had a problem..(well, kick the tail shaft off it once when the mount broke..)
But the tranny has worked great !

1939fiat

 

looks like it does have yoke that bolts onto the tailshaft and it turns out that it is outta a gmc rather than chevy, does that matter? thanks

 

Arn't the heavy duty t/h400's mentioned ealier only found on one tons, plus they have a "P" on the case and larger pan bolts?

 

Like I said earlier you'll need a special yoke that is machined for the O ring on the output shaft, I got mine from Inland Empire for about a hundred bucks.