My 4L80e Build Thread
 

Well something in the trans finally let go during a 1-2 shift last week. I left from a light at light throttle and slowly rolled into it halfway through first gear. Turbo spooled, spun the tires and I stayed in it :burnout: With my foot still in it, it tried to shift into second and BAM. Something loud and metallic. Truck is still very driveable but it will not shift out of first gear until it hits 4500rpm, and then it shifts very hard. I can get it up to about 3000rpm and completly let off the throttle and it will shift into second but I'm not going to drive around like that forever. The day after that happened, I was getting on the freeway going up a hill and trying to pass the car next to me. I was going around 70mph and gave it half throttle and it shifted from 3rd to 1st for some reason. Engine bounced off the limiter violently. Glad I didn't hurt anything else :jest:

So I have the hurt 4L80e that is in my truck right now and then I have one sitting in storage with is a 4wd unit. I'm thinking about driving my truck how it is now and tearing the 4wd unit down and converting it to 2wd. From what I've read, it will only take a longer output shaft, matching tail housing, and maybe changing the output carrier housing with one that has a reluctor wheel on it for the rear speed sensor. I think the 4wd units use a speed sensor that is in the transfer case.

I'm kind of nervous to start the process but any knowledge and help from you guys would be much appreciated. I know a few of you have done your own builds. I have the ASTG manual and some green transmission assembley goo on the way. I'll probably fabricated a bench mount before I start tearing it down.

My goal is to build something solid that will handle 800-1000rwhp. I'm sure parts are going to be expensive :(

Parts arent that expensive actually...I recommend buying from wittrans, they are cheap, good, and fast. Sounds like you maybe broke the intermediate apply piston. The gears stack up on the 80e, so 2nd is 1+2, 3rd is 1+2+3, etc. So if you break the 2nd gear you will only have first and second.

Pm me your email address. I have 2 really good manuals. I used both at the same time to build tranny. Also i have alot of the manuals for the transgonkit and sonnax parts.

Looks like Wittrans just uses a Transtar catalog. I'm already direct with transtar so I'm not worried about those parts. Just out of curiosity Atomic, what upgraged hard parts are you running in yours? I'm thinking I'll need a billet input and main shaft, and maybe a billet forward hub..? I really don't know what I need. Just trying to make it strong enough to not worry about breaking hard parts all the time.

I'll be putting a trans bake in there too. Thinking about going with jakes brake.

Will do BlackGMC. Thanks you. I remember you telling me you did your build so I might be asking for some help from you!

Good luck man my 4l80 was the funnest and most interesting project i have done to date. 3-4 years and 60k later it still works.

Next time mine is opened up its gonna get a 36 element sprag and a couple other goodies in prep for the next stage.

Thanks Corey, I appeciate the pictures and help so far.. Looking through your pictures, I told myself, Damn this is going to be fun. :jest: Can't wait to start this week.


Been looking at Jakes Performance and CK Performance for hard parts. Any other sources you guys recommend? Not sure what I'll use but here are the possibilities.

Billet input shaft - $350
Billet main shaft - $230
Billet rollarized front hub - $150-$280
Direct Drum w/ 36 element sprag - $590
Transbrake - $700

Total - $2150

Don't think I will need the 36 element sprag but I will probably pull the trigger on everything else.

Mine has all CK stuff as far as hard parts.

Good to know.

The billet drum with 36 sprag is much better place to put your $$$ than the main shaft.