Since the first five-speed manual transmission appeared in the Fox-body Mustang in 1983, it's become the standard-bearer for gearboxes in late-model Mustang street cars. While the first '79-'82 cars had various forms of four-speeds, the norm now is clearly to have five forward gears with a generous Fifth-gear overdrive for effortless highway cruising. Even the vintage guys have gotten into the act as the typical T5 has become a virtual bolt-in for '65-'70 Mustangs.
But here (and this will be of interest to you vintage fans, too) we're going to concentrate on the various types of five-speeds that come factory-equipped in Fox and SN-95 Mustangs as well as the best options for a replacement gearbox.
First, a quick history lesson. Many of you have probably heard of two main companies that make the five-speed transmissions found as factory equipment in modern Mustangs or that are a popular replacement-Borg Warner and Tremec. The short version is that Borg Warner and Tremec are now the same company.
Here's how it happened: Borg Warner and Tremec made transmissions and other components for several decades. In 1995, DSA of America-a division of the huge corporation known as Dana-bought Tremec. In 1997, DSA also bought the manual transmission division of Borg Warner. In 1998, another company called Spicer S.A. DE C.V (located in Mexico) acquired Dana's manual transmission division (which included both Tremec and Borg Warner). The U.S. subsidiary of Spicer is now known as Transmission Technologies Corporation (or TTC) with facilities in Michigan and Ohio. So that's how it stands today.
What follows is a review of the current available five-speed transmissions for a street-driven late-model Mustang. The cars that the vast majority of you own have these units and if they're treated well, this article will be just an FYI for you. If you need to replace the five-speed in your car, you have some choices in terms of an upgrade and we'll touch on that, too. You can think of the five-speed transmission gamut for Fox and SN-95 Mustangs in three general ways. First, there are the legions of T5 variants used in all Mustangs from 1983 to 1995. Second, there's the T5's replacement known as the T45 (recently replaced by the TR-3650 in 2000), which came on the scene in 1996 with the introduction of the 4.6-liter modular V-8. And finally, there are the "Tremec" five-speeds, which, with one exception-the 351W-powered '95 Cobra R-are an aftermarket upgrade for late-model 5.0s. That's the basics, now let's look at the details.
Borg Warner (Now TTC) T5
The T5 has been the bread-and-butter for manual transmission Mustangs since 1983 and continues to be the best for the average street car when it's time for replacements. But there are about 40 different versions of the T5 and if you have an older car, this is a perfect chance to upgrade to a better T5 than what you might have now.
The T5 is a relatively lightweight (77 pounds) overdrive-equipped (Fifth gear) transmission that has been subjected to more hard use than it was ever intended to see. As such, it's gotten an undeserved reputation as not being strong enough for semi-powerful street cars. In truth, a T5, when treated well, will work fine behind engines making upwards of 400 horsepower; but only the best versions of the many T5s made over the years.