How to determine the gearing of a T5 transmission.
Most people match the T5 metal tag number (1352-XXX) to the charts on the internet to determine what the gearing is on a particular T5. I have found the charts to be wrong on several occasions. Instead of relying on the charts, I use a simple 5 minute procedure to accurately determine 1st and 5th gears. I then compare my results to the available charts for verification. It would be a shame to buy a T5 thinking that it has a 0.72 overdrive gear when it really has a 0.86.
Please also see the photos following the description below.
To determine 1st gear. Make sure the transmission is in 1st gear. Then, place a piece of tape on the end of the input shaft and mark the 12 o'clock position. Do the same on the drive shaft or output shaft. To determine 1st gear, start with both pieces of tape at 12 o'clock and rotate the drive shaft CCW for ten complete revolutions while counting the total number of turns of the input shaft. Since the input shaft will rotate more than once with each complete driveshaft turn, it must be done slowy while a helper counts turns of the input shaft. Then divide the number of input shaft turns by 10. Example: 10 turns of the DS = almost 30 turns of the input shaft. So 30 divided by 10 = 3. So first gear should be 2.95. Possible outcomes might be 2.95 = almost 30 turns, 3.35 = 33.5 turns, 3.5 = 35 turns, 3.78 = 37.8 turns, 4.03 = 40 turns.
To determine 5th gear. Make sure the transmission is in 5th gear. Place a piece of tape on the end of the input shaft and mark the 12 o'clock position. Do the same on the drive shaft or output shaft. For 5th gear, start with both pieces of tape at 12 o'clock and rotate the drive shaft counterclockwise exactly 10 turns. Your helper should count the turns of the input shaft. Example: If the input shaft makes just a bit more than 8 and 1/2 turns, then the OD gear is 0.86. Other results might be 7 and 1/4 turns = 0.72 or 0.73. Almost 7 and 3/4 turns = 0.76.
Please also see the photos following the description below.
To determine 1st gear. Make sure the transmission is in 1st gear. Then, place a piece of tape on the end of the input shaft and mark the 12 o'clock position. Do the same on the drive shaft or output shaft. To determine 1st gear, start with both pieces of tape at 12 o'clock and rotate the drive shaft CCW for ten complete revolutions while counting the total number of turns of the input shaft. Since the input shaft will rotate more than once with each complete driveshaft turn, it must be done slowy while a helper counts turns of the input shaft. Then divide the number of input shaft turns by 10. Example: 10 turns of the DS = almost 30 turns of the input shaft. So 30 divided by 10 = 3. So first gear should be 2.95. Possible outcomes might be 2.95 = almost 30 turns, 3.35 = 33.5 turns, 3.5 = 35 turns, 3.78 = 37.8 turns, 4.03 = 40 turns.
To determine 5th gear. Make sure the transmission is in 5th gear. Place a piece of tape on the end of the input shaft and mark the 12 o'clock position. Do the same on the drive shaft or output shaft. For 5th gear, start with both pieces of tape at 12 o'clock and rotate the drive shaft counterclockwise exactly 10 turns. Your helper should count the turns of the input shaft. Example: If the input shaft makes just a bit more than 8 and 1/2 turns, then the OD gear is 0.86. Other results might be 7 and 1/4 turns = 0.72 or 0.73. Almost 7 and 3/4 turns = 0.76.
The photos below show how I mark the input and output shaft. Use the procedure outlined below to determine the gearing. It works for any gear. Fourth gear is always a 1:1 direct drive with the input shaft.
STEP 1
1988 V6 F body WC T5 input shaft is marked at the 12 o'clock position.
1988 V6 F body WC T5 input shaft is marked at the 12 o'clock position.
STEP 2
The drive shaft yoke is slid onto the output shaft and marked with tape at the
12 o'clock position.
The drive shaft yoke is slid onto the output shaft and marked with tape at the
12 o'clock position.
STEP 3
Place the shifter into 5th gear (or 1st gear). Then, with both tape marks at exactly
12 o'clock, spin the output shaft in a counter-clockwise direction exactly
10 revolutions. Have a helper count the number of full revolutions of the input shaft.
Place the shifter into 5th gear (or 1st gear). Then, with both tape marks at exactly
12 o'clock, spin the output shaft in a counter-clockwise direction exactly
10 revolutions. Have a helper count the number of full revolutions of the input shaft.
STEP 4
In this example, the input shaft went around 7 full turns plus 6/10 of a turn. Therefore 7.6 divided by 10 equals 0.76 for 5th gear. When I had the shifter in 1st gear, we counted 40 turns of the input shaft. So 40 divided by 10 equals 4.0 for 1st gear.
In this example, the input shaft went around 7 full turns plus 6/10 of a turn. Therefore 7.6 divided by 10 equals 0.76 for 5th gear. When I had the shifter in 1st gear, we counted 40 turns of the input shaft. So 40 divided by 10 equals 4.0 for 1st gear.