The 4L80E is GM's heavy-duty four-speed — built around the 400 case, capable of 450+ ft-lbs, and the right unit behind big-block gas and Duramax diesel applications. Rebuilds need OEM-spec hardware. Bolts that don't torque correctly come back as a leak.
Years
1991-2009
Fits
GM HD trucks (Silverado 2500/3500, Sierra HD, Suburban 2500), Hummer H1
Parts In Stock
Full catalog at Gearbox Insider
Ship Time
Same-day before 2pm ET
Common 4L80E Failures & Fixes
Use this as a starting point for diagnosis. Click through to the specific part once you've narrowed it down.
| Symptom | Most Likely Fix |
|---|---|
| No 2nd gear / harsh 1-2 | forward sprag and shift solenoids |
| Slipping in OD | direct clutch pack and overrun roller |
| TCC code P0741 | TCC solenoid + apply valve |
| Pump leak | pump bushing and pump halves |
| Output shaft seal leak | seal + dust deflector |
What's In the 4L80E Catalog
The full Sonnax-grade aftermarket and OE-equivalent catalog for the 4L80E family is on Gearbox Insider. That's where the inventory lives, ships from, and updates in real-time.
- Master rebuild kits (gaskets, seals, friction modules)
- Valve body kits (Sonnax)
- Solenoid sets (shift, EPC, TCC)
- Speed sensors (ISS & OSS)
- Clutch packs & bands
- Pumps, drums, planets, sprags
- Pressure regulator & boost valve kits
- Bushings, bearings, thrust washers
Why Buy From Us
Spec parts
not "compatible"
not "compatible"
Ship before
2pm Eastern
2pm Eastern
Shipping
no minimum
no minimum
Built by & for
transmission pros
transmission pros
Related Guides
Diagnostic and rebuild guides for the 4L80E on Gearbox Insider:
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