Transmission Rebuild Kits

Is your gearbox worn, does it slip between gears, or does it need to handle more torque after tuning? Here we have collected kits for overhauls and upgrades, typically with seals, friction plates, bearings or reinforced hard parts, for automatic transmissions and certain motorcycle gearboxes.

What does a rebuild kit contain?

The contents depend on the specific kit. A complete overhaul kit from ATS Diesel, e.g. the Master Transmission Overhaul Kit for the Ford 4R100 or E4OD, is designed for a full teardown of the transmission. Hard parts kits from Pure Drivetrain Solutions, e.g. for the 8HP51, are aimed at transmissions that need to withstand more load. There are also more targeted solutions such as the BD Diesel Bypass Tube Eliminator Kit and bearing kits from Hot Rods for motorcycle gearboxes. ISR Performance is also represented in the category.

How to choose the right kit

• Transmission code and model year: the kit must fit your exact transmission, e.g. 4R100, 5R110, 47RH/RE or 68RFE, and the specified model year range.
• Purpose: a standard rebuild or a project with more power. Staged kits (Stage 1-4) typically cover different load levels, but the contents depend on the manufacturer.
• The rest of the drivetrain: higher torque may require the torque converter and transmission control to be adapted as well.

Installation and maintenance

A rebuild typically requires special tools, thorough cleaning of the valve body and correct torque specs, so a workshop experienced with automatic transmissions can be an advantage. Use the fluid specified by the manufacturer, and check the level and any fault codes after the first drives. If the case or shafts are too worn, a complete automatic transmission may be the alternative.

Frequently asked questions

What is the difference between an overhaul kit and an upgrade kit?

An overhaul kit typically contains the wear parts that need replacing during a rebuild, e.g. seals and clutch plates. An upgrade kit may also include reinforced hard parts or a modified valve body. The exact contents depend on the kit.

Can I install a rebuild kit for my automatic transmission myself?

It is possible with experience, special tools and a repair manual. However, an automatic transmission has many small parts and tight tolerances, so many choose to have a workshop experienced with automatic transmissions do the job.

Should the torque converter be replaced at the same time as the rebuild?

It depends on the condition of the converter and your power goals. During a rebuild, debris from a worn transmission can be trapped in the converter, and with more torque a stronger converter may be necessary. Check the manufacturer's recommendation for your kit.