GM Turbo 350 Transmissions: How to Rebuild and Modify
In GM Turbo 350 Transmissions: How to Rebuild & Modify, respected automotive technical author Cliff Ruggles guides you through the complex rebuild procedure of GM's popular rear-wheel-drive automatic transmission. With his proven style, Ruggles goes through the step-by-step rebuild and performance upgrade procedures in a series of full-color photos. He includes instruction on removal and installation, tear-down procedures, parts inspection and replacement, as well as performance mods and shift kit installation. Time-saving tips are part of every buildup as well.
Automatic transmissions are a mystery to most. Even if you end up deciding to have a professional take care of your transmission repair and performance needs, the information contained in this book is crucial to understanding how the power gets from the engine to the road. Add a copy of GM Turbo 350 Transmissions: How to Rebuild & Modify to your automotive library today.
From the Publisher
Although the Turbo 350 is not quite the stout heavy-duty performer that its big brother, the Turbo 400, is, the TH350 transmission is a fine, durable, capable, and when modified, solid performer. Millions of GM cars and trucks have been built with Turbo 350 automatic transmissions. There always comes a time when the old transmission shows signs of wear. At some point, even the best transmissions need a rebuild.
Respected automotive technical author Cliff Ruggles guides you through the complex rebuild procedure of GM’s popular rear-wheel-drive automatic transmission. Ruggles details the step-by-step rebuild and performance upgrade procedures. He includes instruction on removal and installation, tear-down procedures, parts inspection, and replacement, as well as performance mods and shift kit installation. Time-saving tips are also part of every buildup.
A roll-around cart makes a great place to keep your rebuild kit and other parts clean and separated from the work area.
Here’s a common problem with some vehicles that have a rear-located distributor. If the engine isn’t effectively supported, it can lean back and break the distributor cap; in extreme cases it will bend or break the housing!
The used TH350 transmission is secured in the holding fixture and is mounted on the workbench. I have cleaned off a work area and rounded up the tools needed to take the unit apart for inspection. This particular unit was pretty clean. Some units require a good power washing to remove dirt, mud, grease, and road grime before they are taken apart.
Transmission Fundamentals
The TH400 and TH350 transmissions use a gear-type oil pump. The inner gear is driven directly by the hub of the engine’s torque converter. Note that the inner gear is offset in the housing. This creates a chamber that moves oil and forces it out of the pump.
Check the endplay on each pinion as shown. Also spin each pinion and wobble them back and forth. If endplay is beyond .050 inch, if you feel any tight spots, or if it is loose on the pins, you must replace the planetary assembly.
Remove the support plate and then remove the factory separator plate. If the transmission is in the vehicle, you will find four check balls above the plate. They will not be reused because the TransGo shift kit contains new check balls.
The aftermarket offers a hardened outer intermediate sprag race as an upgrade for the TH350 transmissions. It takes more abuse than the stock outer race, but can still fail in a high-torque application if it is used with the stock roller clutch assembly. This happens simply because the load is not distributed evenly to the outer race as it is with the much stronger 36-element aftermarket sprag assembly. The (aftermarket) hardened race in this photo survived 71 high-10-second dragstrip runs behind a high-torque 455-ci engine before it exploded.
Publisher : CarTech (July 1, 2015)
Language : English
Paperback : 144 pages
ISBN-10 : 1613251890
ISBN-13 : 978-1613251898
Item Weight : 1.1 pounds
Dimensions : 8.5 x 0.38 x 11 inches
Price: $31.99
(as of Mar 10, 2025 03:42:26 UTC – Details)
Although not quite the heavy-duty performer as its big brother, the Turbo 400, the Turbo 350 transmission is a fine, durable, capable, and when modified, stout performer in its own right. Millions of GM cars and trucks have been built with Turbo 350 automatic transmissions. There always comes a time when the old transmission shows signs of wear. At some point, even the best transmissions need to be rebuilt.
In GM Turbo 350 Transmissions: How to Rebuild & Modify, respected automotive technical author Cliff Ruggles guides you through the complex rebuild procedure of GM’s popular rear-wheel-drive automatic transmission. With his proven style, Ruggles goes through the step-by-step rebuild and performance upgrade procedures in a series of full-color photos. He includes instruction on removal and installation, tear-down procedures, parts inspection and replacement, as well as performance mods and shift kit installation. Time-saving tips are part of every buildup as well.
Automatic transmissions are a mystery to most. Even if you end up deciding to have a professional take care of your transmission repair and performance needs, the information contained in this book is crucial to understanding how the power gets from the engine to the road. Add a copy of GM Turbo 350 Transmissions: How to Rebuild & Modify to your automotive library today.
From the Publisher
Although the Turbo 350 is not quite the stout heavy-duty performer that its big brother, the Turbo 400, is, the TH350 transmission is a fine, durable, capable, and when modified, solid performer. Millions of GM cars and trucks have been built with Turbo 350 automatic transmissions. There always comes a time when the old transmission shows signs of wear. At some point, even the best transmissions need a rebuild.
Respected automotive technical author Cliff Ruggles guides you through the complex rebuild procedure of GM’s popular rear-wheel-drive automatic transmission. Ruggles details the step-by-step rebuild and performance upgrade procedures. He includes instruction on removal and installation, tear-down procedures, parts inspection, and replacement, as well as performance mods and shift kit installation. Time-saving tips are also part of every buildup.
Tools & Equipment
A roll-around cart makes a great place to keep your rebuild kit and other parts clean and separated from the work area.
Removal
Here’s a common problem with some vehicles that have a rear-located distributor. If the engine isn’t effectively supported, it can lean back and break the distributor cap; in extreme cases it will bend or break the housing!
Disassembly
The used TH350 transmission is secured in the holding fixture and is mounted on the workbench. I have cleaned off a work area and rounded up the tools needed to take the unit apart for inspection. This particular unit was pretty clean. Some units require a good power washing to remove dirt, mud, grease, and road grime before they are taken apart.
Transmission Fundamentals
The TH400 and TH350 transmissions use a gear-type oil pump. The inner gear is driven directly by the hub of the engine’s torque converter. Note that the inner gear is offset in the housing. This creates a chamber that moves oil and forces it out of the pump.
Assembly
Check the endplay on each pinion as shown. Also spin each pinion and wobble them back and forth. If endplay is beyond .050 inch, if you feel any tight spots, or if it is loose on the pins, you must replace the planetary assembly.
Shift Kit Installation
Remove the support plate and then remove the factory separator plate. If the transmission is in the vehicle, you will find four check balls above the plate. They will not be reused because the TransGo shift kit contains new check balls.
Performance Mods
The aftermarket offers a hardened outer intermediate sprag race as an upgrade for the TH350 transmissions. It takes more abuse than the stock outer race, but can still fail in a high-torque application if it is used with the stock roller clutch assembly. This happens simply because the load is not distributed evenly to the outer race as it is with the much stronger 36-element aftermarket sprag assembly. The (aftermarket) hardened race in this photo survived 71 high-10-second dragstrip runs behind a high-torque 455-ci engine before it exploded.
Publisher : CarTech (July 1, 2015)
Language : English
Paperback : 144 pages
ISBN-10 : 1613251890
ISBN-13 : 978-1613251898
Item Weight : 1.1 pounds
Dimensions : 8.5 x 0.38 x 11 inches
Customers say
Customers find the book easy to follow with clear instructions and helpful pictures. They find the information useful and a good reference, supplementing factory service data. The book provides nice illustrations that help identify parts. Overall, customers consider it a worthwhile purchase and reasonably priced for the quality of information provided.
AI-generated from the text of customer reviews
