6-speed or 8-speed?
A 2017 Silverado 1500 has one of two Hydra-Matic automatics, and the RPO code on the glove-box label tells you which one.
| RPO | Transmission | Typical application |
|---|---|---|
| MYC | 6L80 6-speed automatic | 4.3L V6 and most 5.3L trucks |
| M5U | 8L90 8-speed automatic | 5.3L in LTZ and High Country, and all 6.2L trucks |
The 6L80 and 8L90 differ in length, controls and wiring, so they aren't interchangeable. Our 8L90 listings also show the transmission ID (for example 5UJL, 6U7L, 5UZL, 6UGL, 5U0L or 6ULL), which identifies the calibration and drive type. Match the RPO code first, then the ID if your old unit's tag is readable.
Filter by engine: 4.3L, 5.3L or 6.2L.
About 8-speed shudder
If your 8L90 had a shudder or "rumble strip" feel at highway speed, that isn't always a failed transmission. GM's bulletin 18-NA-355 covers torque-converter shudder on these trucks. The fix is a fluid exchange to the updated Mobil 1 LV ATF HP fluid. Use that fluid when you install a used 8-speed.
Install checklist
- Confirm 4x2 vs 4x4. The 4x4 version has a different output and tailhousing.
- Flush or replace the cooler and lines if the old unit failed internally.
- Have the shop program the transmission control module and run the relearn with a GM scan tool.
Some listings on this page are remanufactured units, and the listing title says so. Used units show the donor's recorded mileage and our grade. We report mileage as recorded and can't guarantee it. Every transmission comes with a 2-year limited parts warranty on the case and internal parts when a qualified technician installs it within 10 business days. Labor isn't covered.
Read how to check a used transmission before you buy. Related: 2017 Silverado 1500 engines, 2016 Silverado 1500 transmissions, the 2017 GMC Sierra 1500 transmissions and all Silverado 1500 transmissions.