Product Description
Upgrade your transmission the right way with the TRANSGO ALLISON SK SHIFT KIT, a proven valve body repair and durability upgrade for 2001-2005 GM 2500HD and 3500HD trucks equipped with the Allison 1000, 2000, or 2400 five-speed automatic transmission. This kit is engineered to correct common Allison failures like 3-4 slip, neutralizing under load in 4th or 5th, burnt C2 and C3 frictions, loss of pump prime, no movement after extended parking, and stuck-in-gear conditions. TransGo designed this kit to deliver major durability improvements inside the transmission, including approximately 111% more C2 friction torque capacity and about 100% more C3/C4 brake holding capacity under max line pressure with the lock-up clutch off. For work trucks, tow rigs, and performance-driven Duramax builds, this is a high-value upgrade that attacks known weak points before they become expensive failures.
Fitment
- 2001 GM Silverado 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2002 GM Silverado 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2003 GM Silverado 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2004 GM Silverado 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2005 GM Silverado 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2001 GMC Sierra 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2002 GMC Sierra 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2003 GMC Sierra 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2004 GMC Sierra 2500HD / 3500HD with Allison 5-speed automatic transmission
- 2005 GMC Sierra 2500HD / 3500HD with Allison 5-speed automatic transmission
- Fits Allison 1000, 2000, and 2400 five-speed automatic transmissions
- Note: Five-speed Allison units use an external MLP switch
Why Install the TransGo Allison SK Kit?
- Targets common Allison 5-speed drivability and durability failures
- Helps correct 3-4 slip and neutralizing under load in 4th or 5th
- Reduces risk of burnt C2 and C3 friction damage
- Addresses loss of pump prime and drain-back complaints on early models
- Improves clutch holding power for towing, work, and tuned applications
- Includes critical internal components and springs for a more complete repair
Common Problems This Kit Helps Correct
- Slip 3-4
- Neutralizes under load in 4th or 5th
- Burnt C2 and C3 friction plates
- No movement after being parked for an extended period
- Loss of pump prime
- Stuck in one gear
- Diagnostic trouble codes P0732, P0733, P0734, P0735, P0766, and P0777
What’s Included
- (2) C2 piston orifice cup plugs
- (32) C2 piston return springs
- (2) Drill bits
- (2) USA-made hardened steel trim valves, balls, inner and outer springs
- TCC limit valve spring
- Lube regulator valve spring
- Parking pawl pin and spring
- Extension and pump housing gaskets
Specifications for TRANSGO ALLISON SK
| Specification | Details |
|---|---|
| Part Number | ALLISON SK |
| Transmission Fitment | Allison 1000 / 2000 / 2400 5-Speed Automatic |
| UPC | 810159321310 |
| GTIN | 810159321310 |
| Shipping Info | Calculated at checkout |
| Prop 65 | Not listed on the sources reviewed for this item |
FAQ
What does the TransGo Allison SK Shift Kit fix?
This kit is built to correct common Allison 5-speed problems such as 3-4 slip, neutralizing under load, burnt C2 and C3 frictions, pump-prime loss, stuck-in-gear conditions, and several ratio and solenoid-related transmission codes.
Is this a good upgrade for towing or tuned Duramax trucks?
Yes. This kit is an excellent choice for towing, heavy work, and higher-stress applications because it improves clutch holding power and addresses known weak points in the Allison 5-speed platform.
Which transmissions does ALLISON SK fit?
It fits Allison 1000, Allison 2000, and Allison 2400 five-speed automatic transmissions used in 2001-2005 GM 2500HD and 3500HD trucks.
Does this kit help with loss of pump prime after the truck sits?
Yes. TransGo specifically notes that the included TCC limit and lube regulator valve springs help combat excessive drain-back and pump-prime loss complaints on 2001-2003 models.
Why is the C2 clutch important on the Allison 5-speed?
The C2 clutch is one of the known weak links in these transmissions. This kit is designed to significantly improve friction torque capacity and durability in that area to reduce failure under load.
