World Class & Non-World Class
There are two basic kinds of T-5's, Non World Class (NWC) and World Class (WC). The first T-5 was non-world class. In 1983 and 84 Ford used the Non-World Class T-5 to improve the Mustangs performance and gas mileage. All the V8 NWC boxes had 2.95 first gear set with .68 overdrive. All the main output shaft gears and 1st, 2nd, 3rd, gears riding on a solid output shaft with deep oil grooves to provide lubrication. The lower counter gears spin on straight cylindrical bearings with a thrust washer in front to provide support when under load. All the synchronizer rings are made of solid bronze which are of different size than those found in a would-class T-5. It is because there is no bearing under each gear and the bronze synchro rings that the NWC use the heavy 70w gear oil. Torque rating for the NWC was 265ft/lbs.

1985, Ford introduced the World Class T-5 installed with 3.35 first gear set with a .68od behind the 5.OL. T-5 was also used behind both the standard 2.3L with a 3.97 first gearset and the SVO Mustang. SVO received a one year only 3.50 first gear ratio as the 3.97 gear ratio was too low for the added power of the turbo charged 2.3L. No longer were 1st, 2nd, and 3rd gears spinning on a solid output shaft as needle bearings were installed under each gear to reduce drag. The lower counter gears saw tapered bearings to replace the bronze thrust washer. All main shaft synchro's were fiber lined steel rings to improve rings friction surface while 5th remains bronze. By improving the surface friction the synchro slows the gear faster making for smoother shifts. The design remained the same until 1989. Torque rating remained the same at 265ft/lbs.

1990 to 1993 the stock Ford production V-8 WC T-5 was upgraded with stronger 3.35 gear set by increasing the nickel content to produce a harder, stronger gear. 2nd and 3rd gear ratios were decreased slightly tp provide more torque to the rear wheels. Synchro linings on 3rd, 4th were improved by changing from fiber linings to carbon fiber to further improve the friction surface resulting in better high rpm shifts. A longer throw shifter was installed to "make shifting easier". The speedo drive gear was changed from 7 tooth to 8 tooth. The 8 tooth was a step backwards when installing lower rear axle ratio greater than 3.55 as the driven gear is limited to 21tooth count. Yes, 23 tooth gears are available but do not last long as the teeth are thin and do not mesh correctly. Torque rating jumped to 300ft/lbs.

When the 93 Cobra was introduced, so was the "Cobra Spec" T-5. It was the first T-5 with a front tapered output bearing and steel front bearing retainer. The Cobra boxes also received a reverse gear brake and synchro assembly where there was none before. Just about everything else remained the same. Torque rating was increased to 310ft/lbs.

1994 and 95 were the last two years Ford used the T-5 behind a V-8. With the introduction of the SN95 Mustangs, the bell housings in both 3.8L and 5.0L were made deeper to place the T-5 shifter in the correct location to the body. This in turn made the input shaft longer. The neutral safety switch was eliminated, as it was no longer needed. The GT 5.0L Mustangs received the standard input shaft bearing and aluminum bearing retainer, where the Cobras continued with the tapered or "cupped bearing" input shaft and steel front bearing retainer. Torque ratings for both remained the same as the 93 T-5 models. 4 cylinder T-5s were no longer needed when the 3.8L V6 motor came along and was replaced with 3.35 first gear ratio and a .68od. The only difference between the 3.8L and standard 5.0L T-5 was the input shaft length. Changing input shaft of the 3.8L T-5 with 93 input shaft, will result in a 93 and early spec T-5. Everything else remained the same.

Today's V-6 Mustangs sports the last of the T-5s. The T-5 behind the 3.8L is a 3.35 first gear set with a .68 over drive. What makes these different from the rest is the electronic speedometer trigger. No longer is there a mechanical driven cable system. It has the longer input shaft equipped with a steel front bearing retainer and reverse synchro brake assembly. Torque rating is 300ft/lbs.

Ford also used the T-5 in 2.3L cars through the years. While the 4 cylinder T-5 may appear to be the same, they are not. Most 4 cylinder T-5s received a 3.97 gear set with a .79 overdrive and small input pilot bearing shaft. Four cylinder T-5's should not be used behind a V-8, even when the pilot bearing id is decreased to match. Simply put, they will not hold up. Torque rating ~240ft/lbs. Besides first gear is much too low to be usable behind a high horse power car.