8L90 • 8L90, Multi-Plate Performance Converter
Performance Converter Kit
Part No. GM-RK-25
View Instructions
GM 8L90 captive clutch assemblies are difficult to rebuild and are prone to shudder. OE two-piece stamped covers have bolt plates that are hole-clinched to the front side of the covers, creating thin connections that can crack and leak at higher mileage. Sonnax multi-plate performance converter kit GM-RK-25 replaces the OE cover, captive clutch plate and piston in M5U 8L90 units behind 4.3L and 5.3L engines with a stronger and easy-to-build multi-plate assembly. Full lock-up clutch capacity is increased without affecting shift feel or controlled slip.
- Fully machined, forged cover and piston
- Three high-thermal slipping friction elements
- Two clutch plates with low-wear lobe splines
- Piston seal included
Core identification is critical. See instructions for images of the OE front cover, impeller hub and damper assembly. See also compatible converter part numbers below. These part numbers are most commonly laser-etched on the front cover near the mounting pads. This list is not exclusive and may not include the most recent OE part number supersessions or obscure units.
Core ID Chart for Sonnax Kit GM-RK-25
| Transmission (RPO) | 8L90 (M5U) |
| Engine (RPO) | 5.3L V8 (L83) |
| 4.3L V6 (L8V1 | |
| GM Torque Converter Part Numbers of Compatible Core |
2429 7076 |
| 2429 7075 | |
| 2429 6736 | |
| 2429 6735 | |
| 2428 6976 | |
| 2428 6975 | |
| 2428 4690 | |
| 2428 4689 | |
| 2428 1895 | |
| 2428 1894 | |
| 2427 9376 | |
| 2427 7362 | |
| 2427 4484 |
- Front Cover
- Clutch Plate with Internal Splines
- Clutch Plate with External Splines
- Piston
- Piston Seal
- Core: GM M5U, 4.3L & 5.3L
- Dampered: Yes
- Lockup: Multi-Plate
- Transmission Unit: 8L90
- Clutch Material: HTS
- Turbine Hub Input Spline Count: 36
Where to Buy
- Existing Customers: Contact your sales representative.
- New Customers: Fill out the form and a sales representative will contact you.
Sonnax Performance Converter Kits
Engineered to Deliver Builds that Last
Designed from the ground up to outperform OE and other aftermarket components, Sonnax has you covered with a full line of performance converter kits for gas and diesel vehicles. Offering the widest variety of options in the aftermarket, these innovative kits deliver customized performance and value.
- Small/Large Diameter
- Single-Plate/Multi-Plate/Non-Lockup
- Dampered/Damperless
Related Sonnax Parts
Required
Recommended
