Product Description
Fits: GM 6L80, 6L90 · 2008-up
Core charge: none · Built to order: 2-3 business days
The 1-2-3-4 / 3-5-reverse drum is the 6L80 and 6L90's known weak spot: the factory housing cracks and leaks at its welds, which shows up as delayed or slipping reverse and a 2-3 flare. A used housing that has started to leak has no reliable fix, so we never reuse one. We build your drum on a new aftermarket housing with every piston, seal, spring and clutch new, set both clutch clearances and air-check both circuits before it ships, ready to drop in.
Why buy it built
A drum job is two clutch packs, two selective snap rings, a full set of D-rings, a spring compressor and an air check. Built here, it arrives with the clearances already measured and set and both circuits proven, so the job on your bench is install and relearn. No core to send back.
Every drum includes
- New aftermarket 1-2-3-4 / 3-5-R housing (6L80: with a new caged drum bearing; 6L90: bearing and bushing installed by the maker)
- New 3-5-R apply piston (updated design, GM 24242871) and apply ring: on the 6L80 the Sonnax high-capacity ring, which replaces the OE waved plate with a fifth friction and steel for 25% more 3-5-R capacity (or the OE ring and waved plate if you prefer a factory feel); on the 6L90 the OE 2.000 in. ring
- New Belleville return springs, new 1-2-3-4 piston housing (updated design), aluminum apply piston and bonded balance piston
- A full D-ring and O-ring set and the 1-2-3-4 retaining ring kit
- New Alto High Energy frictions and new steels (3-5-R 5 + 5, or 4 + 4 with the OE ring in a 6L80; 1-2-3-4 5 + 5 on the 6L80, 6 + 6 on the 6L90), new waved and backing plates, clearances set with selective snap rings
- Assembled, clearances set and both circuits air-checked
Choose
Pick your drum (6L80 or 6L90) and, on a 6L80, the 3-5-R apply ring: the Sonnax high-capacity ring (included) or the OE ring for a factory feel. Then upgrade the 1-2-3-4 piston, the 3-5-R pack, the 1-2-3-4 frictions and the steels. Upgrade prices show the difference over the included part. On the 6L90 drum a friction or steel upgrade costs a little more because its 1-2-3-4 pack holds a sixth friction and steel; the price updates when you choose. The Alto G3 Powerpack is built around the OE apply ring and waved plate: in a 6L80 drum choose the OE apply ring with it (the 6L90 uses the OE ring already). Call us to order the Red Eagle Powerpack, or the Z-Pak in a 6L80 drum. The Adapt-A-Case drum clamp lifts the assembled drum into the case: add one if you don't have one.
Fitment
| Transmissions | GM 6L80 or 6L90: choose your drum |
|---|---|
| Years | 2008-up |
| 6L80 is in | half-ton Chevrolet Silverado and GMC Sierra 1500, Tahoe, Suburban, Yukon, Cadillac Escalade, Corvette, Camaro SS and Pontiac G8 |
| 6L90 is in | 3/4- and 1-ton gas Silverado and Sierra 2500HD / 3500HD, Express and Savana vans, Cadillac CTS-V and Camaro ZL1 |
| Condition | New: new housing and all-new internal parts |
| Core charge | None |
| Lead time | Built to order, 2-3 business days |
Before you buy
This drum is built with the 2008-up (2nd-design) 3-5-R piston and its matching inner seal. 2006-2007 units used a 1st-design piston and seal that do not interchange with these parts: call us before ordering for a 2006-2007 unit. Run the GM clutch relearn after installation.
Core Charge
No core charge. You don't need to send anything back.
