The T5 transmission has the honor of having the longest production run than any other American made manual transmission. The transmission was used by numerous automobile manufacturers in nearly a hundred different applications. Jeep too would introduce the T5 to their product line in the early 1980’s. The introduction of a 5 speed transmission into a Jeep was a welcome sight for many; however, for some the strength and dependability still lied in question.
AMC introduced the “T5” five speed transmissions and its 4 speed counterpart the “T4” into the CJ jeeps in 1982. The T5 transmission evolved from Borg Warners lighter duty SR4 transmission that was previously used in both Jeeps and Fords. The T5 introduced tapered roller bearings on the input shafts and output shafts, an improved design over the roller bearing design of the SR4. The transmission was offered behind the AMC 150 (2.5L) Inline 4 cyl. and the AMC 258 Inline 6 cyl (4.2L). The T5 used all helically cut fully synchronized in all gears, with all helically cut gears. The T5 was a top loaded and top shifted transmission. The shifter was located in a removable rear tailhousing section.
The T5 transmission case is 9.25 " long in addition to its 6" tailhousing/shifter assembly for a total overall length of 15.25". The T5 case is cast aluminum as is the top cover. The top cover is retained by eleven bolts to the main case. The transmission typically has a casting # of “13-51” or “13-52”.
The T5 had a 23 spline output shaft connecting it to the Dana 300 transfer case in the CJ models. There was also a small production of 1984 Cherokees with the NP207. The transmission input shaft had a 7-1/2" stick out length from the front of the transmission. The input sh
aft was offered with two different spline count options. Input shafts used with the 258 inline 6 engines had 1-1/8" x 10 splines. The AMC four cylinders had transmissions with a 1” 14 spline input shaft. The pilot tips for both input shafts were .59”.
The T5 transmission was Jeeps first venture into a 5 speed transmission. The T5 does not have a compound low gear but does have all around good gearing ratios of: 1st gear 4.03:1 2nd gear 2.37:1, 3rd Gear 1.50:1 4th Gear 1.00:1 5th Gear .86:1 Reverse 3.76:1
The strength of the T5 has often been debated. It was clearly a better transmission than its predecessor the SR4. It does however have its limits and careful consideration is advised in deciding your best plan of action when contemplating a V8 conversion. Advance Adapters does offer a multi drilled bellhousing to mate a Chevy V8 to the T5. The 712548 bellhousing allows for the retention of the factory clutch pedal configuration. Since we use the same bell housing for Chevy to Ford applications, this bellhousing will also bolt up to popular heavy duty truck transmissions like the Ford T18 and NP435. Customers who choose to use this bellhousing for the T5 have the opportunity to upgrade to other transmissions.