GM Transmissions We Rebuild & Replace
If GM put it in a truck, SUV, car, or van, we've probably had one on the bench this week. Here's a rundown of the units we work on most often.
Got a unit? Call 405.659.6419Late-Model 6-Speed & 8-Speed Automatics
6L80 / 6L80E
Found behind LS / LT V8s in Silverado, Sierra, Tahoe, Yukon, Suburban, Express, Camaro, and full-size SUVs from roughly 2006 onward. Common complaints: harsh 1-2 shift, slipping, P0716, P0742 (TCC). We rebuild these with upgraded clutches, billet TCC, and updated valve body where the symptoms call for it.
6L90 / 6L90E
The heavy-duty version of the 6L80, behind 6.0L and 6.2L applications. Same family, beefier internals. Tougher when it's healthy — and tougher to rebuild correctly when it isn't. We've got it dialed in.
8L90 / 8L45
GM's 8-speeds behind 5.3L / 6.2L L83/L84/L86/L87/LT4 — Silverado, Sierra, Escalade, Corvette, Camaro SS. Notorious for "8-speed shudder" caused by friction-modifier breakdown in the factory fluid. We fix it with the correct DEXRON ULV fluid swap and, when needed, valve body service or rebuild.
10L80 / 10L90
The newest 10-speeds shared with Ford. We diagnose and replace as units. Talk to us before you let anyone tell you it "just needs a tune."
Trucks, Vans, & Heavy-Duty
4L60 / 4L60-E / 4L65-E
Workhorse 4-speed behind countless V6 and small-block V8 GM applications — late-90s through mid-2000s. The transmission that built our reputation. We rebuild a lot of these and they come back with shift quality that often exceeds the day they left the factory.
4L80-E / 4L85-E
Heavy-duty 4-speed for full-size HD trucks, vans, and motorhomes. Bulletproof when built right. We do them as straight rebuilds or with HD upgrades for towing and performance applications.
TH350 / TH400
Classic 3-speeds — and yes, we still build them. Hot rods, restorations, race-only applications. Manual valve bodies and trans-brake setups available.
Allison 1000
Behind Duramax diesel trucks. We service the gasoline-application Allison units and partner for heavy diesel work when it's beyond what makes sense in our shop.
Performance & Built Units
Built motor pushing 800+ HP? Tow rig that needs to actually tow? We can spec and build a transmission to match — upgraded clutches, billet input/output, transbrakes, custom shift kits. Talk to us before you order parts so we can build it once, right.
Pair it with a custom HP Tuners tune and you've got a drivetrain that finally matches what you put into the rest of the truck.
Don't See Yours?
If it's a GM automatic, we likely work on it. Give us a call with your VIN or the year/make/model and we'll tell you straight up whether we can handle it and what it typically runs.