Driveshaft yoke comparison between 4L60E and TH400

[MrPink]

So in my infinite wisdom, I am looking for driveshafts/yokes for my TH400 swap that is behind my LS swap. And while comparing prop shafts between my stock 1995 C1500 4L60E RCLB driveshaft(15004101), and the one for an 88 C2500 TH400 RCLB(12475006), I noticed the yokes are identical part numbers 12542963. The only thing that is different is the overall length, the 15004101 is 70" whereas the 12475006 is 73.75". The cost of the new to me driveshaft is $50 + U-joints lol. Which sure beats getting a custom driveshaft made or even extending mine.

 

[stutaeng]

I'm surprised it shows the same yoke, because the spline count is different.

What is prop shaft? Driveshaft?

I did a 4L80e swap on my ECSB 1500 NBS 2wd. The yoke I got is for the early 4L80e (and apparently also for TH400s). I think I got it from a place called Denny's something. In my case, I didn't have to shorten the driveshaft. I'm not sure if that would be true on the GMT 400.

I was just contemplating cutting the driveshaft and welding it myself though, but I didn't have to.

I think the TH400 is actually closer overall to the 4L60e, but still a bit longer.
? Do you know for a fact it needs to be driveshaft needs shortened? How about a driveshaft from a 88-90 RCLB 2500 that came with a TH400 from the factory?

 

[MrPink]

Yes, prop shaft=drive shaft.

The shaft for the TH400 truck is 3.75" longer. Yeah, the 80E and Th400 are the same. I was surprised that they are the same too as I know the 60E is I believe 30 splines whereas the TH400 is 32.

 

[stutaeng]

Here's the one I bought for mine. I initially bought another yoke, but it was too long. This is the shorter version (I think they actually made like 4 or 5 different output shaft versions, including the RV drum brake set-up for those transmissions?)

T-400, 4L80, 4L85, 6L80 Transmission Slip yoke GM 3R Series 32 spline w/threaded hole in output shaft

GM 3R Series 32 spline T-400, 4L80, 4L85, 6L80 Transmission Slip yoke specifically designed to be used on a T-400, 4L80, 4L85, 6L80 with the Threaded Hole in the Output shaft. This design will replace the truck style bolt on yoke with a car style slip yoke and allow for proper slip travel and...

www.dennysdriveshaft.com

 

[MrPink]

Yeah, I have that one saved already lol. But I am getting the whole driveshaft from a 88 RCLB with a TH400 for $50. I can't even get a yoke for that price, so it works for me.

 

[stutaeng]

You already have the transmission, I assume? Sometimes they come with the yoke...or the driveshaft will come with the yoke if you pull it yourself?

 

[MrPink]

The driveshaft comes with it.

 

[454cid]

Yes, prop shaft=drive shaft.

The shaft for the TH400 truck is 3.75" longer. Yeah, the 80E and Th400 are the same. I was surprised that they are the same too as I know the 60E is I believe 30 splines whereas the TH400 is 32.

27 and 32.

 

[Frank Enstein]

Gm uses the 27 spline on Powerglide, TH200,250,350, 375, 2004R, 700R4, 4l60, 4l60E,4l65E,4l70E, T5, T10 (except Super),Muncie (except M22),Saginaw, and prolly 37 others I forgot.
32 Spline on the on the 400 and 4l80E as well as Super T10 and Muncie M22.

The short tail(4") TH400 is about 2.5" shorter than a 4l60E. The mount is about 3" farther back than the 4l60E and 6"ish farther back than all the others listed above.

 

[Frank Enstein]

The driveshaft comes with it.

Please use 1350 u joints or whatever the driveshaft guy says is stronger. If you have to use an adapter joint put it on the axle end. The idea is if a joint has to fail make it the one in back!