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The 8L90 is GM's eight-speed automatic behind the 5.3, 6.2, and LT-series V8s in the Silverado 1500, Sierra 1500, Camaro SS, and C7 Corvette, roughly 2015 and up. It is a capable transmission, but it is best known for one thing among owners: the shudder. If you have a GM truck or performance car of this era with a vibration at light throttle around 25-55 mph, you are almost certainly feeling the torque converter clutch.
The good news is that a large share of 8L90 shudder cases are fixed without pulling the transmission, through a complete fluid flush and updated software. The bad news is that when a flush does not hold, the converter has to come out, and that is a several-hour labor job. This page separates the two so you spend on the right fix.
The 8L90 Shudder Explained
The shudder is a torque converter clutch (TCC) shudder. When the converter clutch applies to lock the engine directly to the transmission for efficiency, a worn or contaminated clutch grabs and slips rapidly instead of holding smooth. You feel it as a shake or vibration, often described as driving over a washboard road, at light-to-moderate throttle in the 25-55 mph range where the transmission is trying to hold lockup.
GM investigated this extensively and tied much of it to transmission fluid that degrades and to converter clutch behavior. Service action centered on a complete fluid exchange with an updated GM fluid specification plus the latest transmission control calibration. For many owners that combination ends the shudder. When it does not, the converter clutch is worn far enough that only replacement fixes it.
Converter Failure Symptoms
- TCC shudder - the signature vibration at light throttle, 25-55 mph.
- Slipping or flare - RPM rises without matching acceleration as the converter fails to hold lockup.
- Harsh or delayed lockup - a bump or clunk as the clutch grabs late.
- Rising transmission temperature - a slipping converter makes heat, especially towing.
- Stored codes - P0741 (TCC stuck off / performance), P2789 (clutch adaptive at limit), and ratio/slip codes in the P0776/P0796 pressure-control family.
As with any converter diagnosis, confirm before you condemn. Contaminated fluid, a worn TCC solenoid, or software that is not current can all mimic a bad converter. Scan the codes, look at commanded vs actual converter slip on a scan tool, and do the fluid flush first if it has not been done.
Fluid Flush vs Converter Replacement
Start With the Fluid Flush
Because GM's own fix for the shudder is a complete fluid exchange, this is where you start, not where you end. A partial drain-and-fill is not enough; the job calls for a full flush that exchanges all of the fluid, using the correct GM DEXRON ULV specification fluid, followed by the latest transmission control software update and an adaptive relearn. Many shudders never come back after this. Cost is roughly $250-$450, far cheaper than a converter.
Use the correct GM fluid. The 8L90 is sensitive to fluid specification, and the wrong ATF is a common reason a shudder returns quickly after a flush.
Check GM DEXRON ULV fluid
When the Converter Has to Come Out
If the shudder persists after a proper flush and updated software, the converter clutch is worn out and the converter needs to be replaced. GM released updated torque converters to address the shudder, so it matters that a replacement is a current, updated unit and not an old-design part. The transmission must be removed from the vehicle to reach the converter.
Compare 8L90 torque converters
Updated GM Converter Part Numbers
GM revised the 8L90 torque converter during the shudder service campaigns, so the part number superseded over time. When ordering, do not buy on an old number; give the dealer or supplier your VIN and ask for the latest superseded torque converter for your specific application, because the correct updated unit differs between the light-duty (8L45) and heavy 8L90 and between engine families. Reference part numbers owners commonly encounter in the 8L90 family include 24297006 and later-superseded revisions; the parts counter should confirm the current replacement number against your VIN before you pay.
The same caution applies to fluid: confirm the current GM ULV fluid part number for your model year, since that specification was part of the fix. Buying the updated converter and pairing it with the wrong fluid undoes the point of the repair.
8L90 Torque Converter Cost (2026)
| Line Item | Typical 2026 Cost |
|---|---|
| Complete fluid flush + software (shudder fix) | $250 - $450 |
| Updated OEM torque converter (part) | $350 - $600 |
| Fluid for converter job | $120 - $200 |
| Labor (5-8 hrs) | $700 - $1,600 |
| Total converter replacement | $1,300 - $2,400 |
If your truck or car is still within the powertrain warranty, typically 5 years / 60,000 miles, a shudder complaint should be a covered repair. Document the concern and have the dealer perform the flush and software update, and the converter replacement if the flush does not resolve it. Do not pay out of pocket for a shudder fix on a truck that is still in warranty.
Dropping the transmission yourself to reach the converter? Our transmission jack buyer's guide covers the capacity and saddle type you want for an 8-speed automatic.
Fixing an 8L90 Shudder? Get the Parts
From the correct GM ULV fluid to updated torque converters and valve body components, our companion shop gearboxinsider.com stocks what an 8L90 shudder job needs. Same-day ship before 2pm Eastern.
Shop Gearbox Insider →FAQ
What is the 8L90 shudder?
A torque converter clutch shudder felt as a vibration at light throttle, most often 25-55 mph when the converter tries to lock up. GM tied it largely to fluid breakdown and converter clutch wear. A complete fluid flush with the correct DEXRON ULV plus updated software resolves many cases.
Will a fluid flush fix the shudder for good?
Frequently, yes, when it is a full fluid exchange with the correct GM fluid and the latest transmission software, not just a partial drain-and-fill. If the shudder returns after that, the torque converter clutch is worn and the converter needs replacing.
How much does an 8L90 torque converter replacement cost?
About $1,300-$2,400 all-in in 2026: roughly $350-$600 for an updated OEM converter plus 5-8 hours of labor and fluid. A fluid flush, which fixes many shudder cases, is only $250-$450.
Which vehicles use the 8L90?
The 8L90 is used behind V8 engines in the Chevrolet Silverado 1500, GMC Sierra 1500, Camaro SS, and C7 Corvette, roughly 2015 and up. The lighter 8L45 is a related unit in smaller applications.