2010–2013 GMC Sierra 1500 6L80 Transmission Repair
In 2010–2013 the Sierra 1500 V8 trucks use the 6L80. V6 (4.3L) trucks of these years used the 4L60E instead, so we confirm by VIN.
Transmission at a glance
Year-specific notes
- 2010 — 2010 is the first year the 6L80 became the common V8 automatic across the half-ton lineup.
- 2013 — 2013 is the final GMT900 year before the 2014 redesign.
How to confirm your transmission
- Check the RPO code sticker in the glove box: MYC = 6L80, MYD = 6L90.
- The 6L80 case has an integral bell housing and a flat, bolted aluminum pan with a drain plug.
- A VIN lookup or scan-tool module ID confirms the unit before parts are ordered.
Common 6L80 failure areas in the Sierra 1500
Often tied to worn valve-body bores, a leaking lower-body seal, or TCM adaptation issues on this generation.
A frequent 6L80 complaint on these trucks; converter clutch wear and fluid condition are the first checks.
Commonly the 3-5-R clutch pack or its piston seal; a burnt 3-5-R pack is one of the best-known 6L80 failure areas.
Pump bushing or pump wear, sometimes following fluid overheating in towing or Arizona summer traffic.
Diagnostic considerations
- Scan for stored and history codes in the TCM, then review clutch slip and pressure-control data live.
- Check fluid level through the check plug at correct temperature — the 6L80 has no dipstick.
- Road test for converter slip and shift quality under load, then check TCM software level.
Repair or rebuild?
Some problems — software, solenoids, a valve body or a converter — can be repaired without removing and fully rebuilding the unit. When clutch packs are burnt or there is metal in the pan, a rebuild (or a replacement unit) is usually the dependable fix. We show you what we found before recommending either.
Other Sierra 1500 generations with the 6L80
Closely related vehicles
Request a quote for your GMC Sierra 1500
Frequently asked questions
Should I rebuild or replace the 6L80 in my Sierra 1500?
It depends on what failed, the mileage and the condition of the case, valve body and converter. We diagnose first, then explain the options before any work begins.
Do you give prices over the phone?
We don't quote a price before diagnosis because repair scope varies widely. Call 602-725-6800 or request a quote and we'll explain the next step.
Where are you located?
MBN Auto Diesel is at 6602 W Myrtle Ave, Glendale, AZ 85301, serving the Phoenix metro.