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How To Rebuild A T5 Transmission

November 14, 2022  -  Transmission & Drivetrain

10 People Found This Article Helpful

The T5, also known as the Tremec T-5, is a sturdy transmission that’s been around since the 1980s. Initially manufactured by Borg-Warner, this rear-wheel-drive manual transmission is still listed on Tremec’s website and is classified as a moderate-power transmission. It can accept up to 300lb-ft of torque, 300hp of power, and weighs just 75lbs. As Tremec’s most compact transmission, it offers smooth and low-effort shifts, coupled with a 0.63:1 overdrive ratio that brings excellent fuel economy when you’re not driving pedal to the metal. This popular transmission can be found on several General Motors and Ford vehicles, including the Camaro and Mustang of the period.

However, like any mechanical component on a car, the T5 transmission will wear out, and the remedy is a T5 transmission rebuild. You can buy a kit, such as the G-force T5 rebuild kit – just check out our transmissions page for a full range. 

Remember that there are two variants of T5, the World Class (WC) and Non World Class (NWC), which have several differences on the inside, so you must ensure that you purchase the correct rebuild kit. There’s a way to tell, which is to look at the oil filler plug and look at the synchronizer rings. Black rings mean this is an NWC transmission, and gold rings indicate it is a WC transmission. You can also look at the bearing cover situated on the front of the transmission, which is best done when the transmission is out of the vehicle. If the cover has ‘TIMKEN’ or other writing on it, the transmission is a WC, and if the cover is blank, it’s an NWC transmission.

Plan Your Rebuild & Estimate Time

In general, any transmission rebuild will take about 10 hours of work including removal and installation, so factor that in and add an extra day or two for any unforeseen contingencies. Call it a week to be safe unless you’re willing to pull some all-nighters. Oh, you’re also going to want a buddy to help with the heavy lifting.

Removing the Transmission

Before you embark on removing your T5 transmission, ensure that you’ve got all the necessary automotive tools for the task. Sockets, wrenches, including torque wrenches, mallets, screwdrivers, jacks and jack stands, safety gear, and the list goes on. Talk to JEGS, and we’ll help you figure out what you need.

Removing your transmission from the vehicle may vary depending on vehicle make and model, and bear in mind that the bell housings will vary depending on whether it’s a GM or Ford vehicle, as well as the model. If you can get hold of a repair manual for your car, that will illustrate the correct process. You might also find a video on YouTube or forums dedicated to your make and model.


The T5 is surprisingly simple to disassemble, as reported by many enthusiasts. Ensure that you have the right rebuild kit before embarking on this exercise, including the correct type of key slider inserts, as they vary depending on whether it’s a WC or NWC transmission. Take plenty of photos as you go along, as this will help you in the assembly process.

Transmission Rebuild

Now you’re into the meat of the matter. There’s quite a bit to it, so you’d better have a knowledgeable buddy on hand to help you. Ensure once again that your repair kit is on hand and contains everything required for the task. 

Being a simple, top-shifting, single-rail transmission, the shifter forks are built within the top cover, making things reasonably straightforward. Ensure that you inspect all components, as there are multiple areas for wear and tear, and now that you’ve got the transmission opened up, you may as well attend to it all. Shifter forks and tabs, gears, synchronizers, input and output shafts, countershaft, and idler gear, all need a thorough once-over. 

Pay special attention to the gear teeth and synchronizers, as even the smallest amount of breakage or wear can become an issue down the line. Our links will help you out. Don’t forget to use plenty of assembly lube as and when required when putting things back together, and ensure that you have ample stocks of it, plus the recommended transmission fluid. 

Tips & Tricks

Planning to attempt a T5 transmission rebuild or any transmission rebuild? Here are our top tips and tricks.

  • Do your research prior to removing anything. Read up, ask questions, talk to our experts, buy the necessary repair kits, and ensure that you’ve got all the tools you need.
  • Get help. A knowledgeable buddy is helpful, as there are some things that you’ll need a second pair of hands to assist with.
  • Check and double-check that you’ve purchased the correct repair kits for your transmission. We’ve shown you how there are two types of T5 requiring their own distinctive repair kit. Other transmission models may have multiple variants too, with differing repair kits.
  • Set aside plenty of time, plus a buffer. We’ve told you how long a typical transmission rebuild takes, plus a decent buffer to leave, so plan accordingly.
  • Don’t rush it. If you’re tired, the sun is too hot to work properly, or that loose nut just isn’t giving way, take a break, have a cool drink, and re-assess your approach if required. Rushing things means you’re more likely to break or forget something.
  • Always have plenty of transmission fluid, cleaning fluid, and other necessary supplies on hand before starting the job.
  • Don’t underestimate safety gear just because you’re DIYing from home.

Transmissions And Everything Performance From JEGS

Whether it’s transmissions or anything performance-related, JEGS carries it all. Since 1960, when founder Jeg Coughlin decided to start his very own performance parts store, we’ve been recognized by countless customers as carrying the best range of performance parts from the world’s best brands. Check out the huge online selection or visit our Columbus, Ohio, store and see what’s on sale. Great prices, expert advice, and all applicable warranties are part of our value proposition.

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