Alright,

I am installing a TH400 into my 1990 Firebird. The TH400 has a bolt on style yoke installed on it. My question is; To mate this to my stock Driveshaft, do I need that yoke or an aftermarket slip in style? If I keep that yoke, I'd have to make it a 2 pc driveshaft

I am pretty sure that I can use a slip in style yoke. Should apply to 4th gen swappers too, let me know what ya'll are doing!!

Chris

 

you can have a driveshaft made with a slip yoke on the DS and it bolts normanlly to the tranny

 

?? I dont think I want to bolt a 1 piece ds to my transmission.

 

no the ds has a slip yoke made into it....the yoke bolts to the tranny normally but the ds had a slip shaft made into it so it can grow and shrink

 

I think I see what you mean. Wouldn't need a carrier bearing right?

 

no basically the ds is telescoping

 

You have a truck tranny like i do (which is a good thing, low first gear). I had to have my Yoke machined down on the inside (where the splines are) about 3/4" deep so the yoke would clear the non-splined part of the tranny's output shaft and go all of the way into the tranny. Without machining, the standard Th400 yoke would stop about 3/4" from the end of the tail housing.

Here it is all of the way in before machining:



I took pictures after machining but they are not on my computer. I just went a .010" larger than the output shaft, 3/4" deep.

 

FYI, that's a standard car yoke for 1350 series universal I have. My driveshaft length was 43-7/8" long from center of yoke (pulled out 3/4") to face of rearend yoke (center to center basically). I have a moser 12 bolt by the way and a 4" tailhousing.