The $600 Five-Speed Swap

America might rank near the bottom of the barrel among industrialized countries when it comes to standardized math scores, but by golly, we know bogus arithmetic when we see it. According to many Pro Touring guys, real street machines need a minimum of six forward gears for performance and streetability purposes. While we appreciate cars that can accelerate, turn, and brake like stink, do you really need a double-overdrive transmission to roll your car off a trailer and jockey it around a parking lot full of cones? Something just doesn’t add up. Anyone who answered yes probably has the means to blow $2,000 to $3,000 on a prebundled manual trans conversion kit. There’s nothing wrong with that, as these setups are pretty slick, and let’s face it, someone has to stimulate the economy. However, for those on a more modest budget, that kind of money might be more than your entire car is worth. Fortunately, stepping outside the blister-pack norm and exercising a little bit of creativity can get you on your way to banging gears like a hoodlum for peanuts.

Using a pile of secondhand parts heisted from a Fox Mustang, we swapped the C4 out of a ’72 Maverick for a junkyard T5 while keeping the tab under $600. Anyone with basic fabrication skills and the fortitude to perform some creative engineering can pull off a similar swap and save a ton of money in the process. The T5 weighs 30 to 50 pounds less than a modern five- or six-speed and is also cheaper. Because the lowly T5 boxes have served as the whipping boys for everything from Fox Mustangs to third-gen Camaros to light-duty trucks for decades, a junkyard T5 can be had for as little as $200. Compare that with a used T56 that will set you back at least $1,500. Furthermore, in a car with a mild 302 small-block that weighs just 2,700 pounds, such as a Maverick, the extra torque capacity of the fancier stuff just isn’t necessary.

As much as we’d like to take credit for this swap, we happened to be in the right place at the right time. While hanging out at Bill Buck Race Cars (BBRC; BillBuckRaceCars.com), the crew got to work on a low-buck Maverick. While Buck’s claim to fame is tuning the chassis on NMRA Outlaw 10.5 Champion Mike Murillo’s 3,000hp ’93 Mustang, he keeps his skills sharp wrenching on more pedestrian projects. As always, plenty of unexpected challenges came up—ranging from potential flywheel imbalance to trans tunnel clearance issues—but we’ll show you how to iron them all out.

Class Warfare

First introduced in 1980, the T5 boasts the longest production run of any five-speed overdrive manual transmission in history. As such, the T5 has been built in a variety of configurations and gear ratios. All T5s fall into one of two categories: World Class (WC) and Non World Class (NWC). The primary difference between them is that World Class T5s were designed to be exported worldwide and consequently feature improved synchronizers and bearings over NWC transmissions. From the outside, WC and NWC are nearly indistinguishable. WC T5s have a tapered bearing race beneath the input shaft while NWC units have a nontapered race. Ford began installing NWC T5s in the ’83 to ’84 Mustang. The V8 models got a 2.95:1 First gear ratio and an 0.63:1 Overdrive, and we’re told they can take up to 300 hp on street tires.

In 1985, Ford switched to WC T5s all across the Fox platform, and several internal improvements were made. To reduce drag, gears One to Three were mounted on needle bearings, which replaced thrust washers on the countershaft. Likewise, new fiber-lined steel synchronizers improved durability and allowed for easier shifting at high rpm. Since most 5.0L Mustangs were equipped with relatively tall 2.73:1 or 3.08:1 ring-and-pinion sets, First gear in these units checked out at a deep 3.35:1. For the ’90 to ’93 models, Ford beefed up the First gearset with a higher nickel alloy and added carbon-fiber linings on the No. 3 to No. 4 synchronizers. These changes bumped torque capacity from 265 to 300 lb-ft.

As the Fox platform morphed into the SN-95 Mustang in 1994, Ford continued using the T5. The trans was nearly identical to earlier T5s but had a 5⁄8-inch-longer input shaft. Since four-cylinder Mustangs were no more, both V6 and V8 Mustangs now used similar T5s. The V8 model had ’90- to ’93-spec gears, while the V6 T5 had the ’85 to ’89 gearset. With the introduction of the mod-motor V8 in 1996, the T5 was no longer used in V8 applications, although it did continue to serve behind V6s until 2010. The next major change for the Ford-spec T5 came in 2005, when the shifter was relocated from the tailshaft housing to the body.

The oddballs of the T5 family are low-capacity boxes usually found in four-cylinder cars. They came with a very deep 3.97:1 First gear, and with torque capacities ranging from 175 to 230 lb-ft, they aren’t suitable for service behind even a weak small-block. If you find one, you might be able to convert it to V8 specs with a gear change, as they usually aren’t beat up.

Sources:

Bill Buck Race Cars; Austin, TX; 512/837-4999; BillBuckRaceCars.com

Modern Driveline; Caldwell, ID; 208/453-9800; ModernDriveline.com