P0218 on Chevrolet: How to Diagnose & Fix
Transmission Over Temperature Condition
2 Chevrolet models · 2 documented issues · 1 critical · $150-$3,500 repair
P0218 on Chevrolet by model: symptoms, diagnosis and fix
The 4L60E 4-speed automatic behind the Vortec V8s is the single most common major failure on high-mileage Tahoes. The 3-4 clutch pack is the known weak point: its friction plates burn up, and the truck suddenly slips or drops out of 3rd and 4th gear (RPMs flare with no acceleration), leaving effectively only 1st and 2nd. Later-production units (roughly 2004+) used thinner/cheaper clutch material and tend to fail earlier. Contributing factors include worn shift solenoids, a leaking valve body/accumulator, TCC solenoid failure, and neglected/burnt fluid. Many owners hit this between 120k-180k miles.
Common Symptoms
- Sudden loss of 3rd and 4th gear
- RPM flares/slipping with no acceleration
- Harsh or delayed 1-2 or 2-3 shifts
- Burnt-smelling dark transmission fluid
- No overdrive / won't shift above 2nd
How to Fix
Verify fluid level and color first (burnt/dark red = internal wear). Scan for solenoid/pressure codes. A slipping 3-4 clutch means an internal rebuild or a remanufactured unit: budget for a rebuild with a heavy-duty (Alto/Raybestos) 3-4 clutch pack and updated Sonnax valve-body parts, or install a reman 4L60E. Address the TCC/shift solenoids and a fresh filter at the same time. Preventive fluid+filter service every ~50k miles and an added transmission cooler markedly extend life on these trucks.
Sources for this issue (1)
Silverado 1500 trucks with the 8L90 eight-speed (and the older 6L80 six-speed) can run dangerously hot when the factory transmission thermal bypass valve sticks closed, so fluid never reaches the cooler — common under towing or heavy load. Sustained temperatures above ~220-250°F oxidize the fluid and cook the clutches and torque converter, accelerating the separately-known shudder/wear and shortening transmission life. Compounding this, the transmission cooler lines and fittings are a frequent leak point on these trucks, dropping fluid level and worsening heat. Owners towing in hot climates are most affected.
Common Symptoms
- High transmission temperature, especially while towing
- Burnt-smelling or dark transmission fluid
- Harsh/erratic shifts as fluid degrades
- Red transmission fluid leak / low fluid level
- Transmission goes into limp/reduced-power mode when hot
How to Fix
Verify transmission temperature behavior and inspect the cooler lines/fittings for leaks. Replace or delete/upgrade the failed thermal bypass valve so fluid reaches the cooler, repair leaking cooler lines/fittings, and service with fresh Dexron-VI fluid. Adding or upgrading an external transmission cooler is a common preventive measure for trucks that tow. Confirm fluid level and condition, as low/oxidized fluid both causes and results from overheating.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Transmission fluid cooler thermal bypass valve (OEM) - 2015-2018 8L90 8-speed, 3/8" linesOEM13561467Cross-refPPE 125071000 (billet aluminum, full-flow upgrade w/ magneti, ACDelco 13561467$90–$160
Fits 2015-2018 Silverado 1500 5.3L and 6.2L trucks with the 8L90 8-speed and 3/8" cooler lines.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
P0218 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0218 mean on a Chevrolet?
P0218 stands for "Transmission Over Temperature Condition." This code means the transmission fluid has gotten too hot and exceeded a safe temperature limit. The transmission's temperature sensor reported an overheat condition to the computer, which can be caused by an actual overheating situation or by a faulty sensor reporting a false reading. Excessive heat is one of the most damaging things for an automatic transmission, breaking down the fluid and accelerating wear, so this code should be addressed promptly. The vehicle may enter a reduced-power or limp mode to protect the transmission. On Chevrolet it is documented across 2 models: Tahoe, Silverado 1500.
What are the most common causes of P0218?
The most common causes of P0218 are: Low or old/degraded transmission fluid, Faulty transmission fluid temperature sensor, Clogged or restricted transmission cooler or lines, Heavy load/towing or stop-and-go driving overheating the fluid, Slipping clutches generating excess heat, Faulty cooling fan or radiator (shared cooling) issues, Internal transmission wear or restriction. The specific cause varies by vehicle.
How much does it cost to fix P0218 on a Chevrolet?
Published repair estimates on Chevrolet range from $150 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0218 on a different make?
View P0218 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.