How to Install a GM Turbo 350 Automatic Transmission

by John Stevens J.D.

The Turbo Hydra-Matic 350 was one of General Motor’s most commonly used transmissions in the late 1960s. The Turbo 350 was a fully automatic transmission that featured three forward gears. The transmission used a fairly basic design, consisting primarily of a three-element hydraulic torque converter and a simple compound planetary gear set. Like all transmissions, the Turbo 350 eventually needs to be either rebuilt or replaced. The process of installing the transmission is fairly straightforward.

Removing the Transmission

1

Park the vehicle on a level surface. Release the parking brake.

2

Remove the bolts that secure the driveshaft to the front of the differential with an open-end wrench to release the driveshaft. Pull the driveshaft out of the transmission.

3

Turn the integral nut at the tip of the speedometer cable in a counterclockwise direction with an open-end wrench until the nut is loose. Pull the cable out of the transmission.

4

Pull the rubber vacuum line off the vacuum modulator located at the back of the transmission.

5

Turn the integral nut at the tip of each oil cooler pipe in a counterclockwise direction with a flare-nut wrench until the nuts are loose. Pull the pipes off the transmission.

6

Remove the bolt and nut assembly that secures the shift linkage rod to the driver’s side of the transmission with a socket wrench, then pull the linkage rod off of the transmission.

7

Support the underside of the transmission with a jack.

8

Remove the bolts that secure the rear transmission mount to the vehicle’s frame with a socket wrench.

9

Remove the four bolts that secure the crossmember to the underside of the transmission with a socket wrench. Two bolts are on each end of the crossmember.

10

Remove the converter-to-flex plate bolts located at the front of the transmission with an open-end wrench.

11

Remove the transmission-to-engine bolts with an open-end wrench.

12

Raise the transmission slightly with the jack. Slide the transmission rearward from the engine and lower it away from the vehicle.

Installing the Transmission

1

Guide the front of the transmission into the back of the engine with the jack, ensuring that the converter-to-flex plate bolt holes align.

2

Install the transmission-to-engine bolts with an open-end wrench.

3

Install the transmission-to-flex plate bolts with an open-end wrench.

4

Position the crossmember against the underside of the transmission. Install the crossmember’s four bolts with a socket wrench.

5

Install the bolts that secure the rear transmission mount to the vehicle’s frame with a socket wrench.

6

Install the bolt and nut assembly that secures the shift linkage rod to the driver’s side of the transmission with a socket wrench.

7

Position the two oil cooler pipes against the transmission. Rotate the integral nut at the tip of each pipe in a clockwise direction with a flare-nut wrench.

8

Push the rubber vacuum line onto the nipple in the center of the vacuum modulator located at the back of the transmission.

9

Position the speedometer cable into place against the transmission. Rotate the integral nut at the tip of the cable in a clockwise direction with an open-end wrench until the cable is secure.

10

Slide the front of the driveshaft into the back of the transmission. Install and tighten the driveshaft’s four retaining bolts with an open-end wrench to secure it to the front of the differential.

11

Pour about 9 quarts of fresh transmission fluid into the transmission’s dipstick tube.

12

Start the engine. Allow it to run at a fast idle for about two minutes.

13

Add transmission fluid if necessary. Note that the distance between the “ADD” and full (“F”) marks on the transmission’s dipstick represents one pint.

Items you will need

References

About the Author

John Stevens has been a writer for various websites since 2008. He holds an Associate of Science in administration of justice from Riverside Community College, a Bachelor of Arts in criminal justice from California State University, San Bernardino, and a Juris Doctor from Whittier Law School. Stevens is a lawyer and licensed real-estate broker.

Photo Credits

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