How Do I Change a Tail Housing on a 700 R-4?

The 700 R-4 transmission is very popular and widely used among car enthusiasts as a retrofit for older model restorations. It is a relatively simple design; and even though it was only in production for eight years, it is well supported by aftermarket manufacturers. Replacing the tail housing is not an uncommon task. If the drive shaft becomes damaged, the aluminum housing could also become unserviceable. The tail housing is also referred to as an extension housing or tail shaft housing. Be sure to inspect the drive shaft, especially the universal joints, when this job is performed.

• 1

  Raise the rear of the car with a jack and lower it onto jack stands. Securely place the jack stands under the frame and make sure the vehicle is stable before proceeding. Use a wrench to remove the four nuts that secure the U-bolts holding the rear universal joint in place. Lever the rear U-joint out of the rear-end yoke and wrap the joint in masking tape to hold the U-joint bearing caps in place. If the caps come off, needle bearings could inadvertently become scattered about, and the joint will have to be replaced.

• 2

  Pull the drive shaft out of the 700 R-4 transmission. Position a drip pan underneath the tail shaft housing to catch the dripping transmission fluid. Use a 3/8-inch socket wrench to remove the four mounting bolts that hold the housing to the main transmission body. Pull off the housing and set it aside.

• 3

  Remove the old gasket. No gasket sealer is ever used when assembling automatic transmissions except on the oil pan. Wipe the area clean and install the replacement housing along with a new gasket. Install the four bolts and tighten them in a criss-cross manner. Do not over-tighten the bolts to avoid stripping the aluminum threads.

• 4

  Install the drive shaft and seat the rear U-joint into the rear-end yoke. Remove the masking tape. Insert the U-bolts and tighten the nuts with a wrench to secure the drive shaft in place.

• 5

  Raise the rear of the car with the jack and remove the jack stands. Check the drip pan and estimate the amount of recovered transmission fluid. Top off the transmission with the same amount. Start the engine and check the transmission for leaks.