Hello,

I have an 09 Silverado it's a 2wd 4.8 with a 4L60. The 4l60 went bad and I want to turn it into a wild prerunner one step at a time so I thought it was a great time to do a 4l80 swap. The swap is done I've done everything on this forum to the letter.

4L60E to 4L80E conversion in a GMT900

I have a 04 4l80 that I rebuilt all new bands, high energy frictions, new steels, seals, bushings, filters, new pump assembly, the direct drum was ring cut, so put in a new direct drum, Transgo HD2 shift kit. It's got a Jegs 3000 stall billet torque converted Part Number: 555-60414. New driveshaft yoke, a 4l80 shifter linkage, modified the cross-member, new AN trans-lines (I used 4l80 specific connectors so that there is no rear oiling issue), auxiliary trans cooler, new dipstick, the swap is done it's in the truck and all the wiring and pin removal and swaps adding the speed sensor was all done according to the above link. I got a new tcm with the van info on it.

Heres my problem I got HP tuners and as soon as I downloaded the tune the truck it popped up with a check engine light and the dash read "SERVICE STABILITRAK" and "SERVICE TRACTION CONTROL" now the thing is it didn't have the check engine before I downloaded the tune from the truck, I hooked up a little Bluetooth code reader and the code is U0100 which I looked up is an unknown issue. It seems to have the error if I use the original TCM or the new one. I used 2 credits on the truck but when i try to load the unedited ecm tune back to the truck it asks for more credits I emailed tech support a whole bunch of times after some unhelpful generic answered I finally got:

"Hi Campbell,
The Infolog you've provided shows no ECM or TCM. BUt I do see the license for the vehicle. So maybe something is not hooked up as they should be showing up in the Infolog. This could also be your issue with the relicensing. I would make sure everything is connected and powered up correctly Pull a new Infolog and it you see an ECM/ TCM try to write the file. If you still get an Unlicnesed vehicle then send me the file you're trying to write."

The other issue is there does not seem to be the little gear indicator square around any of the drive modes "PRND123" the truck doesn't seem to know what gear it's in. The 4L60 I took out did not have a neutral safety switch nor even the plug on the harness for a neutral safety switch, it seemed to work just fine and I don't even have a place to plug one in. I'm not the first owner of this truck but it ran and drove a bunch of miles before the 4l60 gave out.

I figured I would put this out there now the battery is dead because it's been sitting there for a couple of months at this point I put a charger on it, I'm going to try to start it again this weekend we'll see what happens (it's at my girlfriend's parents house because they have a lift). I tried to crank it and the headlights dimmed no crank so I don't know if it's just a weak battery or something preventing it from cranking because of the code, I'll find out this weekend and update this thread. I'm stumped if you can figure this out you're a lot smarter than me. If you need any details just ask.