The T5 is a great street transmission for small-block Fords as long as you don't treat it
This is the era of the manual transmission. Sure, automatics are easy and comfortable, but there's nothing like rowing through a sweet five-speed and listening to a motor sing through the gears. For the Ford clan, the T5 has become the attractive, lightweight overdrive trans of choice. Ford has been building World Class transmissions by the thousands since 1985, so we thought we'd take a close look at the choices for rebuilding or buying Ford-based five-speed transmissions.
If you're not already aware, there's a whole industry built around this stout little transmission. The T5 is not for everyone, and it's certainly not suited for either big-block or nitrous use, but there are all kinds of uses not only for the T5, but also for its aftermarket performance derivatives like the Tremec 3550/TKO five-speeds that have now become the latest-generation Tremec TKO 500 and 600 boxes.
For this story, we took apart a basic 3.35 First gear T5 and went through it to show you some of the highlights of assembling a T5 with an all-new gearset from our pals at D&D Performance. If you're in the market for a five-speed, we've done much of the research for you.
If you want a good swap trans, look for a '90-or-later Mustang with a T5 in the boneyard,
History of the T5
While the '83 5.0 Mustang is where performance enthusiasts were first introduced to the T5, its lineage can be traced all the way back to the '81 AMC Spirit. The trans has been used in well over 200 applications and continues to appear in multiple production applications. The T5 can be split into two main categories: the early Non-World Class (NWC), rated at 265 lb-ft of torque capacity, followed by the World Class (WC) version beginning in 1985, rated at the same torque. The WC boxes are the only ones worthy of performance applications, but they still exhibit a couple of weak areas. We've outlined the gear ratios for all these boxes below. There are myriad T5 boxes used just within the Mustang world. D&D offers a chart on its Web site that identifies specific boxes along with their gear ratios and torque capacities.
While the World Class tag sounds impressive, the reality is that it wasn't until 1990, when Ford updated the T5 to 310 lb-ft of torque, that the transmissions could really be used in any kind of aggressive performance capacity. The latest version, the so-called "Z" box that was used in the '93 Cobra, is equipped with the best of all the updated parts including hardened gears, shortened shifter throws, a bearing collar made of steel, and tapered output-shaft bearings. The trans is available through many sources, such as D&D and Ford Racing.
The Ratio GameThere are two categories of T5 transmissions used in the 5.0 Mustang, commonly differentiated by the First-gear ratio. There are also varying Third- and Fourth-gear ratios, depending on the year of the trans. This information comes courtesy of The Official Ford Mustang 5.0 Technical Reference & Performance Handbook by CC alum Al Kirschenbaum. It covers in excruciating detail all the tech information you'll need on 5.0 Mustangs. You can buy the book from Ford Racing or through Summit Racing.
| ||1ST ||2ND ||3RD ||4TH ||5TH ||REVERSE |
|'83-'84 ||2.95:1 ||1.94:1 ||1.34:1 ||1.00:1 ||0.72:1 ||2.76:1* |
|'85-'89 ||3.35:1 ||1.93:1 ||1.29:1 ||1.00:1 ||0.68:1 ||3.15:1 |
|'89-on ||3.35:1 ||1.99:1 ||1.33:1 ||1.00:1 ||0.68:1 ||3.15:1 |
|Tremec 500 ||3.27:1 ||1.98:1 ||1.34:1 ||1.00:1 ||0.68:1 ||3.01:1 |
|Tremec 600 ||2.87:1 ||1.89:1 ||1.28:1 ||1.00:1 ||0.64:1 ||2.56:1 |
|Tremec 600 ||2.87:1 ||1.89:1 ||1.28:1 ||1.00:1 ||0.82:1** ||2.56:1 |
*Ford also offered a 0.63:1 Overdrive ratio in 1983.
**This trans is the road-race option where the rpm drop between Fourth and Fifth is much narrower.