I just about am ready to crank my truck with the new LQ9/4L80 combo, but I have to get my driveshaft put in it and fill it with trans fluid. However, I pulled the bolt-on style yoke off the 4L80 tonight to find out that my crank has the short splines with the oring. The yoke I bought is the yoke and a Moog 447 ujoint. The problem I am having is that when I slide this slip yoke in the transmission, bottom it out, and then pull it back out ~1", it only leaves me with about 1-3/4" of thread engagement due to the short threads. Is there a way to remedy this? Any help will be appreciated. I want to get this thing running this weekend if possible.

Thanks.

 

When I did my swap, I used 3-3-4261X and a 447 ujoint. It looks like the 4261x is longer.

 

Well, after a little more searching it seems like I need a slip yoke with a counterbore to slide over the O-ring. My slip yoke that I bought has splines all the way to the end of the yoke (which would work perfect on an 80e with the fully splined output shaft), but the splines hit the o-ring before the slip yoke slides far enough into the trans.

Anyone know a part number for the correct counterbored slip-yoke that will work with this O-ringed output shaft?

 

I found a part number in another thread for a slip yoke that works in this application, and it has the 3R ujoints that the stock driveshaft comes with. It has a 6" long shaft, and it is counterbored 2" to clear the larger diameter or the shaft once it gets past the splines.

Part numbers are below for anyone looking in the future. The other guy that bought this one did say he had to cut 5/8" of an inch off of the end of the yoke, but it works perfect other than that. Bought these from Denny's Driveshaft

NEAPCO N3R-3-9131X slip yoke
Dana Spicer 5-795X u-joint

 

im in the process of doing the same thing, what year truck and what drop do you have on it?

 

I’d really like to know this info also.

in addition, can someone explain which years of the 80 have short and long shafts?

 

OP's last activity on the forum was may of 2019
His last post in this thread was in 2018
I wouldn't hold my breath for a response

 

I used that yoke for my 4L80e swap. There are 2 different yokes. The one listed is a long th400 yoke. The other is a short th400 yoke. There is less thread engagement, but I've known people that put it right in and they haven't had any issues.

I cut 5'8" off of it and it went right in. Was able to use a normal 3r u joint. Still have the 2 piece stock driveshaft and had it high speed balanced. Was able to take it up to 140ish with 3.73s, 31.22" tire, in 3rd gear.

My truck is a 2001 Silverado ECSB with a 2" drop shackle in the rear.

I know there is a thread that listed the differences in the 4L80s by year.

 

how long was that freak'n yoke?

he means 5/8" im sure lol

some transfer case yokes also will work that have the same spline count i got one dont remember from what cut about 3/4" off beveled the end then installed it, when i did it, it was to get me by till i ordered the correct one witch i did but never installed it been about 20k+ miles now