Racing Transmission Build - Make It A Muncie

The T10 replaced the Muncie transmission in many GM cars in the early '70s, and although they look nearly identical to the untrained eye, they actually have very few interchangeable parts. Here is a T10 case; you can identify it because the bottom of the opening for the side cover is curved.

Here, the Muncie's bottom side cover opening, however, is straight.

For almost every rebuild Cook says a small-parts kit is a necessity. It includes new snap rings, shims, and most important, new needle bearings.

When rebuilding the Muncie, check the shafts for wear. Here, the center shaft is pitted from use and should be replaced. If it isn't, it will damage the needle bearings, quickly wear the main gear and cause broken teeth.

Before beginning assembly, Cook drills and taps a hole in a boss in the bottom of the case for a drain plug.

This is the input shaft. It uses a set of needle bearings that are held in place by a cage. Cook inserts the bearings into the cage first, using heavy grease to hold them in place, and then he installs the completed assembly into position.

There are four rows of 20 needle bearings each inside the main cluster, and there is no cage to help hold them in place. Cook uses lithium grease to hold the bearings against the ID of the cluster, a small screwdriver to aid in positioning the bearings, and truckloads of patience.

Cook drives the inner race onto the main shaft. This race is what First gear rides on, but it is still necessary even with First removed, because it also locates the mid-plate bearing.

This is the mid-plate with the bearing installed. However, it isn't the stock bearing. Cook has located a heavier-duty bearing and uses it instead. It features more balls inside the bearing and provides smoother operation and more protection for the shaft.

This is the stock hook slider that the shifter forks move to determine what gear is used. Notice how the teeth inside the slider are straight cuts. Cook says this is a problem with the Muncie because the teeth will allow the transmission to pop out of gear unexpectedly.

In all of his racing rebuilds, Cook uses a hook slider like this. On this aftermarket piece, there is an angle cut on the sides of all the teeth which locks the gear in place when the car is accelerating. No more popping out of gear.

Cook gently taps the slider into position.