8L45 Clutch Drum, remanufactured and ready to install. Fits the 8L45. Ships fast from the USA.
This is a remanufactured GM 8L45 clutch drum that houses two clutch packs: C4, the 2-3-4-6-8 clutch, and C5, the 4-5-6-7-8-Reverse clutch. Those two packs are involved in seven of the eight forward gears plus Reverse, so a cracked drum, a worn piston bore or a leaking seal surface here produces complaints almost everywhere. Owners of 8L45-equipped Camaro, Colorado, Canyon and Cadillac ATS, CTS and CT6 models usually arrive at this part after a teardown shows a damaged housing, or after a 3-4 flare, slipping above third, or a slow Reverse engagement that a relearn would not fix.
The 8L45 makes eight forward ratios and Reverse with five clutches, C1 through C5, always holding two or three at a time. GM bulletin 16-NA-019 lists which clutch applies on each shift: C4 applies on the 1-2, 5-6 and 7-8 upshifts, while C5 applies on the 3-4 upshift and is the clutch learned on the Neutral-to-Reverse garage shift. The drum carries the plates, pistons, return springs and apply chambers for both packs, fed through sealing rings from the stator support. If the drum leaks apply oil, the transmission control module keeps adding pressure and time to compensate until it runs out of adapt range.
Rule out the cheap causes first. Sonnax documents a 3-4 neutral caused by swapped S8 and S9 solenoid connectors, with no clutch damage at all, and worn S1/S5 clutch control valve bores that bleed off C5 apply pressure. Our 3-4 clutch failure guide covers both, plus GM's 3-second input speed test for a delayed Reverse. Bore wear in the valve body is covered in the valve body symptoms guide. If the learns fail and the valve body checks out, air check the C4 and C5 circuits with the pan off. A pack that leaks down or will not hold air is a drum, piston or seal problem.
This drum is listed for the 8L45 without a specific year, so match it to your unit before ordering. That matters because GM changed the C4 side in 2018: the piston and dam piston were redesigned to stop cracking, the seal groove dimensions changed and a new wave plate was added. GEARS Magazine notes the early and late seals are not interchangeable and the late wave plate does not work with the early piston housing. Compare the drum with your original, check the piston and seal dimensions, or send us your year and VIN. The 8L45 does not share this drum with the 8L90; if you have the larger unit, see the 8L90 clutch drum. The 2015 8L45 clutch drum is a separate listing, and everything for this family is on the 8L90 and 8L45 collection page.
| Fits | 8L45 |
| Part type | Clutch Drum |
| Condition | Remanufactured |
| Brand | GM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It holds C4, the 2-3-4-6-8 clutch, and C5, the 4-5-6-7-8-Reverse clutch. Between them they work in seven forward gears and Reverse.
Not without checking. GM changed the C4 piston, seal grooves and wave plate for 2018, and the early and late seals are not interchangeable. Compare it to your drum or send your year and VIN.
Maybe, but check the S8 and S9 solenoid wiring and the S5 clutch control valve bore first. Both cause a 3-4 neutral with healthy clutches.
New C4 and C5 frictions and steels, pistons and seals for the correct year, sealing rings at the stator support, and fresh DEXRON HP fluid.
Yes. Clear the adaptives and run the C4 and C5 learn procedures from GM bulletin 16-NA-019 with fluid between 35 and 95 degrees C.
