Guys, I'm having several issues with my swap, just looking for some help as I'm about to lose it. Truck in sig, 2007 NNBS 4.8, factory 4l60e swapping to 2003 4l80e.

First, it feels like my drive shaft is binding under load, is this u joint pushed too far into the trans? I used my factory shaft with a 80e yoke pressed on, just like RedHeartbeat did, I have a flip kit however. Are there different length 80e yokes?




Also, I'm losing trans fluid from this area. It's weeping out of a small hole in the center of the yoke, from the back side. Running down the u joint, and either dripping on the ground if I'm still, or slinging it around if I'm in motion. Cause for this? Too much fluid? Bad rear seal?

Now, for the biggest problem. The 80e has a longer first gear, I added a 3200 Circle D, and I have lousy 3.23 gears. Still, this thing takes waaaaay too much throttle to get it moving. I can't even get it to climb a set of auto ramps. Something isn't right. I worked with Brian (Area47) and Joey (JoeyGC5). Brian has HPTuners, Joey has EFI live. Apparently HPTuners is unable to flash the TCM separately, so Joey did it with his EFI live. Brian then copied the file to HPT so he could further tune later on. My speedometer isn't working, and I honestly can't tell if the trans is even in first gear. It feels like limp mode or something, and acts as if it is trying to start in 2nd gear since it takes so much throttle to move.

Finally, on a short test drive, my trans started whining, it does it while trying to accelerate. The pitch would go up with revs. Did I just waste my converter as well? Or the pump? I was almost positive I seated the converter all the way, but this is my first time messing with one. Sounded almost like a supercharger whine.

I know I'm asking a lot, but any suggestions to these problems? I'll double check anything you guys throw at me.

Here is RedHeartbeat's thread with everything he did to swap, I tried to follow it word for word. 4L60E to 4L80E conversion in a GMT900

 

Oh **** that yoke is to far in. The tune needs to have a bit of tweaking to work better with the stall converter. Brian should be able to do this. It is possible the trans is in 2nd gear from a dtc or fault condition when starting from a stop. When I left and you took off I was going to ask you to see if you could cycle through the gears starting in 1st, but you took off to quickly.

 

Sounds like an electrical/wiring issue and you are in 2nd gear, which is the default limp mode.

You need to have the dshaft shortened. Might have worked for the other guy, but obviously isnt working for you.

Sure it has enough fluid? Pump whine isnt good...

 

Shaft can be shortened, definitely not something I wanted to do, but I can deal with that. How much yoke is supposed to be showing in front of the joint? Do I need to shorten it about an inch or so based on the pics?

I'll tear it apart and double check ALL wiring I changed. Make damn sure that I removed and swapped the right pins, and used the correct ones for the ISS, and that the 45 to 26 swap in the TCM was done correctly per RedHeartbeats thread.

 

The trans is moved back 1 11/16" I believe, so around that. Best option is to measure and have a custom shaft made.

 

The whine is normal for the 4l80. Mine has always done it pretty good.

As far as the dshaft goes that thing is way too far in there. Seal is gone most likely. Depending on which flip kit you have it may or may not move the axle back. Mine (belltech) does move the acle back a bit to account for the decreased angulation if the shaft with the drop.

 

I haven't heard an 80E in good working condition make a "normal" whining noise. Not sure what you're experiencing here.

As for the leak, that is not the seal leaking. On that yoke, if the u-joint was removed you would see a plug that is pressed into the end of the yoke. That press-fit plug is leaking. Not uncommon at all. To repair it, you can usually get away with cleaning it very well, then seal it with a thin layer of GMS.

As for the length of your driveline... It's hard for me to tell from just looking at your picture. I don't see many 2WD trucks up here. But judging from your driveline angles, I'm betting your truck is lowered. When you unbolt the rear u-joint, how much farther does the yoke go into the transmission before it bottoms out? I'd like to see about 1 1/2" of end play.

 

Yes, it is a lowered 2wd. 4" front, 7" back. I'm not positive if the flip kit I have (Belltech) moves the axle forward or rearward on the NNBS RCSB trucks. I didn't take measurements before I did it.

The whine definitely doesn't sound anywhere near normal. It wasn't making this noise within the first couple miles of my test drive. The T5 trans in my 91' s10 has a slight whine to it when you're hard on the gas, but this is much more present.

Thanks AK for the tip on the leak, I'll look into that. It has no play forward when unbolted from the rear. It was actually difficult to get the rear u joint past the edges of the pinion yoke. That should have thrown a red flag to me.

 

I had an 80e that sounded like a school bus it whined so loud...

 

im at a loss on this one. t42 file swapped with efi live. fired up, displayed showed up right. went to pull the file with hpt, freaked the **** out when it tried to pull the trans tune. pulled the files with efi live, then hpt it went smooth. can't see what trans codes it threw without the tech2 on it.

aside from spending 100 bucks on credits to flash the 4.8/4l80e file from the van onto it, im out of idea's.