DIY T-5 Transmission Rebuild is Easier Than You Think (Video)

By Cameron Vanderhorst - April 20, 2020

With a press, some hammers, and a whole lot of patience, just about anyone can rebuild their own transmission.

The newest episode of Power Nation’s Muscle Car outlines a project that many Mustang owners are reluctant to tackle on their own. In this video, they’ll fix a chipped third gear on a Borg Warner T-5 transmission.

This video starts right off by asking, “How confident are you in your wrenching?” Indeed, even the most experienced gearheads usually leave transmission work to the professionals. Hopefully, we’ll learn something from this video.

With prices for clean Fox Body Mustangs steadily climbing, many are starting out with a cheaper four or six-cylinder car, then swapping over to a V8. That’s just what the Muscle Car guys did.

Unfortunately, Muscle Car’s junkyard five-speed reveals that it had serious issues on the test drive. A cursory examination uncovers an unsettling amount of metal shavings and things just get worse from there as they disassembled it.

With the top cover off, it’s easy to see the problem. Host Tommy Boshers is shocked. “Well, I found the reason why it wouldn’t go into third. There’s not much of one left!” Third gear looks like it just went twelve rounds with Tyson at his peak.

Like most complicated car parts, disassembly is surprisingly easy. Reassembly is where things get complicated in a hurry. It’s a trap that has snared generations of would-be gearheads.

Putting It All Together

Boshers is replacing more than just third gear. All of the components are being replaced with upgraded parts from American Powertrain. Surprisingly, you can complete most of the work with hand tools — mostly hammers. The only shop equipment you’ll need is a press.

Taking lots of photos and having everything laid out logically will go a long way towards making sure you don’t miss anything, or put anything back in the wrong order. Taking a lot of photos and having access to a shop manual is also a great plan. Lastly, the most important tool you can have in your arsenal when you’re rebuilding a transmission at home is patience.

As he buttons up the re-assembly, Boshers gives us one last bit of great advice. “Before we can put the top plate on, you need to make sure the transmission is in neutral.” After making sure the input and output shafts rotate in both directions, he re-installs the top case cover.

After the tail-housing and shifter are re-installed, Boshers measures the end play on the main shaft. If you find any endplay, you must install a spacer on the retainer to keep everything from moving. Even the slightest bit of movement could grenade the transmission you just rebuilt in short order.

Boshers closes out the video with a statement we can get behind. “Now, rebuilding a transmission may not be for everybody. But they’re not near as mystical as people make them out to be.” While we won’t be rebuilding our own transmission any time soon, we’re not nearly as intimidated as we once were.