The Auburn Hills, Michigan-based Borg-Warner, Inc. has produced three types of five-speed manual transmissions over the years: The T-5, T-45 and the T-50. Each transmission has distinct physical characteristics that can lead to accurate identification. Most Borg-Warner transmissions feature a stamped casting number, but physical characteristics often pinpoint the exact type of transmission. Borg-Warner supplied manual transmissions to numerous automakers, most notably General Motors and Ford. For decades, the Borg-Warner transmission has been the manual gearbox of choice in Ford Mustangs. Transmission Technologies Corporation, also based in Michigan, bought Borg-Warner in 1998 and continued building five-speed manuals.
Determine the make and model of the vehicle that features the T-50. Borg-Warner produced the T-50 for the 1976 to 1979 Chevrolet Monza and Buick Skyhawk.
Use a creeper to position yourself under the car, if the transmission is still in the vehicle. Inspect the end of the case facing the rear of the car. The transmission has an aluminium end-loaded housing with a bearing retainer integrated in the main case. The bellhousing features a removable tube.
Examine the side of the case -- you should see stamped on the case the casting number 13.38.
Inspect the transmission once it has been removed from the vehicle to determine whether it's a Non-World Class or a World Class model. Examine the bearing case below the input shaft bearing, on the main case. The WC version has tapered roller bearings, while the NWC features flat roller bearings. The synchroniser is made of solid bronze and the sizes are different between the NWC and WC. The NWC is equipped with the heavier Dexron II bronze synchro rings.
Remove the bellhousing, using a wrench set. Inside, the NWC has a cover that looks more like a freeze plug. The WC version has a heavy steel cover stamped with "Timken" and a part number. The WC also featured a black and yellow "Use Dexron II only" label to identify the transmission fluid.
Inspect the identification tag affixed to the case. For example, a tag with "1352-001" identifies the transmission as belonging to a 1982 to 1983 AMC passenger car.
Determine the make and model of the vehicle using the T-45. The 1996 to 1999 4.6-litre Mustangs received the T-45. The Tremec 3650 replaced the T-45 in 2000, after Tremec bought Borg-Warner.
Inspect the T-45 transmission once it's outside the vehicle. Examine the case -- it should be made of aluminium, with a separate bellhousing and tailhousing.
Inspect the speedometer gearing of the transmission. There are two versions of the T-45 for the Mustang GT and the Mustang Cobra. Each feature different speedometer gearing. The Cobra has a seven-tooth speedometer gear, while the Mustang GT has an eight-tooth speedometer gear. In the T-45's final production year, all 1999 Mustangs have the seven-tooth gear.
Search the exterior of the case for the casting number. All T-45s have a "1381" casting number stamped on the case.
The transmission should be outside the vehicle to properly identify the type of five-speed manual gearbox.
Interchangeable parts in the T-50 and T-45 five-speed manuals are non-existent. Do not attempt to mix and match T-5 parts with T-50 and T-45 transmissions.