GM 4L80E 4-Speed Heavy-Duty Electronic Automatic · GM/Chevrolet/GMC/Cadillac/Buick · Expert rebuild service since 1987. Lifetime warranty. Free diagnostic.
1991–2013 Chevrolet/GMC HD trucks (2500/3500); 1991–2006 Chevrolet Express/GMC Savana vans (HD); 1994–1996 Cadillac Fleetwood; behind 6.0L/6.5L diesel and 7.4L/8.1L big-block gas engines
| Configuration | 4-speed automatic with overdrive — TH400 lineage, heavy-duty electronic |
|---|---|
| Gear Ratios | 1st 2.48:1 · 2nd 1.48:1 · 3rd 1.00:1 · 4th 0.75:1 · Rev 2.07:1 |
| Fluid Type | Dexron VI ATF |
| Fluid Capacity | 13.5 qts total, 7.0 qts service refill |
High-mileage 4L80E units in HD truck applications develop output shaft seal leaks and output shaft wear, causing ATF to leak at the rear of the transmission.
Symptoms: ATF leak at rear seal; puddle under vehicle at back of transmission; wet driveshaft
The 3-4 shift solenoid in the 4L80E fails at high mileage, causing either a fixed 3rd gear (limp mode) or no 4th gear engagement.
Symptoms: Stuck in 3rd gear; won't upshift to 4th; P0758 code
Heavy-duty TCC wear in towing applications causes shudder at highway speed under light throttle.
Symptoms: Shudder at 45–60 mph under light load; clears under hard acceleration
Full disassembly. Output shaft seal and bearing inspected. Solenoid pack replaced. TCC inspected. All clutch packs replaced with heavy-duty Alto kits. Valve body rebuilt. Full soft parts. Converter flushed.
Dexron VI every 30,000 miles. HD truck applications: service every 25,000 miles. Add deep-sump pan for towing. Check rear seal at every service — rear seal leaks worsen fast.
Significantly — the 4L80E is derived from the TH400 platform and handles 440 lb-ft stock, more with upgrades. The 4L60E is rated for 360 lb-ft. Different applications entirely.
Most likely a 3-4 shift solenoid failure or its circuit. The 4L80E defaults to 3rd-gear limp mode on solenoid failures. Solenoid pack replacement typically resolves it.
Yes — very popular LS swap choice for high-power builds. Requires an adapter harness since the 4L80E uses a different connector pattern than the 4L60E.
200,000+ miles with regular Dexron VI service. One of the most durable truck automatics GM ever built.
$1,800–2,600. 2–3 day turnaround.
Free diagnostic, written estimate, lifetime warranty. Chicago's 4L80E rebuild specialists since 1987.
