Coan 12107 master overhaul kit for the GM Powerglide 2-speed: clutch frictions, steels, gaskets, seals and sealing rings for a full teardown rebuild.
Rebuilding a Powerglide for a bracket car, a gasser or a classic Chevy that has started slipping into high gear? The Coan Racing 12107 master overhaul kit puts every wear item for a stock-style aluminum Powerglide in one box: five direct (high) clutch frictions, five reverse clutch frictions, the matching steels, gaskets and sealing rings. The band and the filter are not included, which lets you pick the band that suits your build.
The Powerglide is a two-speed with one planetary set, a low band and two clutch packs. In Low, the band clamps the drum and the planetary gives the reduction. For the shift to High, the band releases and the direct clutch pack applies to lock the gearset at 1:1. Reverse uses the reverse clutch pack, and on a race car the transbrake applies the reverse clutch against Low to hold the car on the line. Every apply depends on the sealing rings and piston seals holding pressure, and the frictions are what actually wear out. When either goes, the high gear shift flares or slips, the car creeps on the transbrake, or the trans leaks. This kit renews both halves of that system at once.
A shift flare is not always clutches. BTE points out that a band adjustment that is off causes slow or flared shifts between Low and High and rolling on the transbrake, so check and reset the band first: torque the adjuster to 72 in-lb, back it out three and a half turns and lock the nut. If the problem stays, drop the pan and look at the fluid and debris. Our ATF color and smell chart shows what burnt clutch fluid looks like, and the flare versus slip guide explains how to tell a timing problem from a clutch that is failing.
This kit is built for the GM aluminum-case Powerglide two-speed found behind Chevrolet passenger cars into the early 1970s and the aftermarket race cases that use the same internal layout. The clutch count matters: this is the 5-direct version. Coan sells separate overhaul kits for its 9-clutch Super Drum (12107D) and 10-clutch Big Dog units (12107E-R), so count the frictions in your direct drum before ordering. Early cast-iron Powerglides are a different design; if yours is an iron case, send us the details first. If your reverse pack sees heavy transbrake use, consider upgrading it with the heavy duty Powerglide reverse frictions in place of the stock-style reverse plates. Browse more transmission rebuild kits for other units.
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No. It includes five direct and five reverse frictions, steels, gaskets and sealing rings. The band and filter are sold separately so you can match them to your build.
Not if the drum is the 9-clutch Super Drum or the 10-clutch Big Dog. Coan makes separate kits for those (12107D and 12107E-R). This 12107 kit is for the 5-clutch direct drum.
The transbrake holds the car by applying the reverse clutch while in Low. Worn reverse frictions or a band that is out of adjustment let the car creep. Reset the band first; if it still rolls, the reverse pack needs replacing, which this kit covers.
Torque the band adjustment screw to 72 in-lb, back it out three and a half turns and tighten the lock nut. Recheck it periodically through a race season, since the band stretches and wears.
The kit is built for the aluminum-case Powerglide and race cases that copy its layout. Early cast-iron units are a different design, so contact us with your case details before ordering for one.
