Experienced GM 8L90 specialists since 1987. Free computer diagnostic, lifetime warranty on rebuilds.
GM's 8-speed 8L90 launched in the 2015 Silverado and immediately developed a reputation for shudder and harsh shifting. GM issued multiple technical service bulletins and PCM reflashes. The root causes are a combination of TCC shudder, valve body tolerance, and clutch pack break-in issues. We've developed a rebuild process that addresses all the known failure points.
| Speeds | 8 |
| Type | Automatic |
| Fluid | Dexron HP |
| Fluid Capacity | 11.4 qts total |
| Max Torque | 800 Nm |
| Weight | ~218 lbs |
The 8L90's torque converter clutch shudder is its most notorious problem. GM issued TSB 16-NA-155 and multiple PCM updates, but the root cause is often the converter clutch material and fluid degradation.
Symptoms: Vibration/shudder at 25–50 mph under light throttle
Valve body tolerance variation causes harsh or inconsistent 1-2 shifts, especially when cold. PCM updates help but don't fully resolve mechanical wear.
Symptoms: Clunk on 1-2 upshift, worse in cold weather
The 3-5-R and 4-5-6-7-8 clutch packs wear prematurely in trucks used for towing or performance driving.
Symptoms: Slip in upper gears, flare on upshifts, burning smell
The integrated solenoid body develops internal wear causing pressure inconsistency and shift quality degradation.
Symptoms: Erratic shifts, P0751 through P0775 range codes
"Honest diagnosis, fair price, and the repair was done right. Chicago Transmission has been my go-to for years. Wouldn't trust anyone else with my car."
"The free diagnostic alone was worth the trip. They found the problem fast, gave me a written estimate, and completed the work on time. Exceptional service."
"Family owned and it shows. They treated my car like it was their own. The lifetime warranty on my rebuild gives me total peace of mind. Highly recommend."
It's annoying but usually not immediately catastrophic. However, driving with TCC shudder accelerates clutch wear — fix it before it becomes a full rebuild.
If you're in warranty or have an extended warranty, yes. Out of warranty, you're on your own — that's where we come in.
The 8L45 is for smaller engines (4-cylinder Camaro, etc.) with a lower torque rating. The 8L90 is the truck/V8 version. Both share similar failure points.
With regular Dexron HP changes, 120,000–180,000 miles. Neglected fluid is the #1 killer.
Yes. C7 Corvette 8L90s come through occasionally — same rebuild, different installation due to dry-sump routing.
Bring it to Chicago's most experienced GM 8L90 shop. Free diagnostic, written estimate, no obligation.
