I'm going through the 80E in my 95. It came out of a 96 3/4 ton diesel truck with 130,000 miles on it. Fluid was discolored and had tons of debris in the pan when I got it. It has a transgo shift kit and the TCC and AFL valves have been redone in the valve body. The clutches that were visible with the valve body off looked great but 3rd doesn't hit anywhere near like 2nd and 4th do so I know the direct clutch is weak and likely where all the debris came from. I would like to build it to handle 1000+ hp. I just ordered a Yank SC3000 to replace the stock converter that was used with the diesel engine. Do I need to be looking at a full rebuild kit or just replacing the direct clutches and anything else that might be worn? If a full kit any particular brand or just go with stock clutches and steels? I know somewhere along the line there was a sprag that got upgraded. Is it necessary and do I need it for mine? I know there is a lot of information out there for 2001+ 80Es but being that mine is older I thought I would ask before getting anything else for it.

 

With a 130K I would do a full build. Most of the info for the later units will still apply with your earlier unit. The big difference is in the lube flow for some of the hard parts. Just make sure if you swap any hard parts to keep this in mind. At 1000 rwhp you should definitely upgrade some of the hard parts. Input shaft, main shaft, forward clutch hub, and intermediate sprag are a few that come to mind. Good luck with your build. Vince

 

It had 130k on it when I put it in and now has more like 150k on it. Other than 3rd not being as firm as 2nd and 4th it has performed flawlessly. When you say the lube flow is different and that if I swap hard parts to keep that in mind what exactly do you mean by that?

 

Everything from the center support back uses a different style lube system so the hard parts change some. I guess my point was if you change anything make sure you match is up so you don't melt anything down.

 

To be honest I don't plan on changing much. These things take a hell of a beating with not much more than a shift kit. I think the 34 element sprag is worth while but I don't plan on changing out any of the shafts. What brand of clutches do you like to use? Any particular site to shop for parts?

 

I normally use Borgs in these builds and get most of my soft parts from WIT. If you call them ask for Bill Maddox and tell him Vince from TDE sent you!

 

Look at the output shaft.. most mid 90's 80e's did not have a slip style yoke..so the splines are very short. But for about 50.00 you can get the slip on style output shaft with long splines and the lube hole.

 

Mine was intended to have the bolt on yoke but I took a slip yoke style yoke and cut it down to length and run it on my otherwise stock two piece drive shaft. The yoke is more of less fixed but can float a little as needed. Not a bad idea though as the splines are very short.

Wouldn't the tail housing have to be changed too?

 

Time to revisit this. I've got a yoke located for free at work. Its currently on an aluminum rear shaft out of a 08 1/2 ton 4wd. Its the nickle plated yoke with external clips for the 1310 or 1330 u joints, whichever my truck uses. I believe its the same exact one I got 3 years ago that I cut down to work on the 80E's current bolt on yoke style output shaft.

So now then is this the correct output shaft for my application?
4L80E Output Shaft 90 - 96 Slip in Yolk 2WD tail | eBay

This one says its a bolt on yoke output shaft but it appears to be the same and in better condition IE not rebushed.
GM 4L80E SHAFT OUTPUT 2WD USED BOLT ON YOKE 8 1/8 | eBay

With the 2wd slip yoke output shaft will I need to change tail housings? I would think yes but I'm not familiar with the 2wd 80Es outside of mine. Just don't see them much and the ones I have were all bolt on yoke 2 piece driveshaft trucks.


I think I found the kit I need on WIT. I believe its part number B34006EA. Is there any reason to replace the pistons? I read that there is a 34 as well as a 36 element sprag? Which one do I need to get?

I believe I found the correct output shaft on WIT. Part number U34678Q and I would think it would be new correct?

I think this is the extension housing from WIT. Part number U34770EA 6 5/8" long housing.

And lastly the internal wiring harness because mine is leaking at the connector. Part number 34446AK

Thanks for the help guys.

 

Bump.