My son's pickup lost all 4 Forward gears yesterday. Reverse still works fine. Said he was accelerating moderately up a slight grade, and about the time of the 2-3 shift, he heard/felt a "bang", and it essentially hit neutral. He coasted into a lot, and got a tow back home.
Trans was "cold", (first drive of the day, 5-6 blocks from home, although the weather was hot).
It took a look at it today, and tried 1, 2, 3, D, all were like being in neutral. Reverse did move the truck.

Guessing it was a hard part that broke, and will require R & R/Complete overhaul.
Looking for ideas on possible culprits.
1/2 ton, 2008 ext cab, bone stock 4.8, 130K miles.

Thanks in advance, haven't done a 4L60E before, but the boneyards seem to want stupid money for them around here, ($1500-$1700 for a USED, 130K mile unit? Seriously?? Which could be 5 miles from having the same exact problem?)
Master overhaul kits are around $300-375. Figured I might as well give it a go... I am sure it needs at least one additional part in there, and probably will upgrade servo & sun shell while it is apart.

Had the same thing happen on my 03 avalanche, lost forward, reverse was fine. Dropped pan and found treasures in it. Being a 4wd and me not having a lift, I opted to take it to AAMCO. Forward drum cracked, and the rest of the discs and plates were pretty burned. New trans, convertor and labor $3,000, 100,000 mile warranty. Mine had 170k miles on it, and I do a lot of towing with it.

What a coincidence. I am rebuilding my first trans too which is a 4l60e. I thought about getting this kit http://www.transmissionbench.com/4L60Eparts.html but I ended up going to a local trans parts store. What drew me to this site was his videos on YouTube. They’re awesome! https://m.youtube.com/watch?v=SK84Qy_Vu_E

I just had a new 4L60 built for my Camaro by Super Stock racer and customer Tim Wudarczyk. We put everything in it new. TransGo kit, 5 pin planetary, all the stuff to make it live.

I sold the unit that came out of the car for $450.. Nothing wrong with it, just could find anyone who wanted it.

Just wanted to provide an update on this thread, and share some info that was learned along the way. Also want to give a shout out to those who shared advice on here, and the PM's from a couple of the guys.

We did successfully rebuild the 4L60E, it is back in his truck and runs great. I now have a better understanding of why transmission shops charge a lot to rebuild these units. It takes much more time to disassemble and put together than a simple older 2 or 3 speed unit. There is a lot to the insides of these electronic controlled overdrive trannies, including 5 different clutch packs, multiple planetaries, solenoids, sprags and other items that can require replacement. So not only does a shop need to allow for more work hours, but they need to hedge their bets because unless it is a basic case of worn or burned clutches, there can be several additional parts required. Plus we added a couple of recommended upgrades, (Servo Assy and Sun Shell).

Ours was a series of failures that resulted from one disintegrated Torrington thrust bearing, which ground itself into steel paste, and kind of began a domino effect, that cascaded into other parts issues from front to back of the trans. Had to replace the forward sprag assembly, input sun gear assembly, input planetary carrier/reaction shaft, and the output shaft.

Two Important things to know if you have a 4L60E, (or the non-electronic 700R4):
1. Change your fluid and filter more frequently than you might think. Like maybe every 30K miles or so, especially if you tow with it. Seriously, there is a lot of precision stuff in there you need to keep bathed in clean fluid.
2. Use Dexron VI fluid, NOT the Dex III stuff that the owners manual specifies!! Apparently GM issued a bulletin on this some years back, I never heard about it until we were doing our research on this trans. (Lucky You - Autozone has ALL their ATF on sale right now, 2 quarts for $12. That includes synthetics, which is what Dex 6 is).

Total cost was around $650, that included the Master overhaul kit, an upgraded "Corvette" style 2-4 Servo assembly, molded pistons, new valve body separator plate, seals, gaskets, bushings, new output shaft, sun shell, forward sprag assy, input planet carrier assy, new converter from O'Reilly, ($145 - Not Bad!), pump rebuild kit, and 12 quarts of Dexron VI.

Props to TransmissionBench.com for posting 7 hours of videos on YouTube, nicely broken up into 18 segments, covering the entire overhaul procedure very well. (Thank you Wine-O1 for that tip)!

I buy my oil and trans fluid at wal****s, way cheaper than parts stores. I paid $17 for 4 quart jug of trans fluid there.

Awesome to hear, glad it worked out!