Borg-Warner T15 Transmission
In 1969 Jeep introduced the stout T15 3 speed transmission. The T15 was initially brought to market to handle the Buick V8 engine. The T15 was an obvious improvement over the T14 and would prove to be quite reliable behind not only the Buick 350, but the AMC 258, and AMC 360 as well. Although the T15 was only used for 4 years, the transmission deserves the reputation for its strength and reliability.
The T15 offers a completely helical cut gear set and is synchronized in all forward gears. The T15 would follow coarse with the T14 and offer a sliding clutch collar rather than sliding gears. This addition would prove essential for the strength needed to handle the bigger V8’s. The transmission gear ratios for this transmission are 3.00:1 first gear, 1.83:1 second gear, 1:1 third gear and 3.00:1 reverse
The T15 case is cast iron as is the top cover and is retained by 8 bolts. The case features two large shift rail protrusions on the driver side of the case. These shift bosses were used as a side-shifting mechanism. They were normally not used for most applications; However Jeep Waggoner service manuals clearly show a column shifted T15 option as late as 1972 that used these side shifting actuators.
The T15 transmission measures in at 10” in over length and weighs approximately 100 lbs. The T15 may have the following casting numbers: T15 or 1307, or 13-07-065-901 and are found on the passenger side of the transmission. The front bolt pattern of the T15 is the same as the T14, but the case length easily identifies the T15. Another easy identification difference is the front bearing retainer. The T15 used a four-bolt front bearing retainer while the T14 used a three-bolt front bearing retainer. The rear of the T15 was always a 1-3/8" x 6 spline output shaft for mounting to the input gear of the transfer case. The T15 was used exclusively behind the Dana 20 transfer case.
The T15 transmissions were available with a few different input shaft configurations. The T15 always had a 1-1/8" x 10 spline input shaft with a .75” pilot. The stick out length was generally 8.50”; however, we have seen variations of up to 2-3” longer. These somewhat rare applications may require an input shaft swap when using one of our adapters.
Although many Jeep vehicles utilized a V8 with the T15, The cost of rebuilding older AMC engines towers over rebuilding a Chevy of Ford. This coupled with the T15’s reputation for strength makes it an excellent transmission choice for a Chevy or Ford V8 conversion.
The T15 had a relatively short run for jeep. It was certainly one of the stronger 3 speeds used by Jeeps. By 1976 Jeep had discontinued The T15. It was clear, American consumers were looking for more than just a three speed and for many it was found in the T18. Jeep was not quite done with three speeds though. With the retirement of the T15, a new 3 speed would be introduced. It would be known as the T150 and would prove similarly strong as the T15.