The Stovebolt Site Forums The Shop Area Driveline which speedo gear for T5 to a 56 3100

I have a T-5 #1352-145 which is .072 5th mated to a 3.90 rear end and 225/75R-15 tires. I want to replace the speedometer gear in the t-5 transmission. Does any one know which one I need or how to caculate which one i need?

Second question. How long is the speedometer cable from the speedometer to the tranny do I need?

Thanks guys

A 225/75R-15 tire is 28.29" in diameter.

You need to match the Drive Gear (inside the T5) with the Driven Gear (the one inside the metal plug that's on the end of the speedometer cable).

I had an S10 T5 (1352-145) with the 0.72 OD gear. It had a red 9 tooth Drive Gear inside and a 20 tooth Driven Gear.

If you also have a red 9 tooth Drive Gear, the calculations show you need a 25 tooth Driven Gear for correct speedometer readings. However, I don't think the 25 tooth Driven gear is available in the aftermarket.

If you switched to a 7 tooth Drive Gear, then you could use a 20 tooth Driven Gear.

Another option would be to use a 0.7333 ratio reducer with a 9 tooth Drive Gear and an 18 tooth Driven Gear.

I used this website to make the calculations above.

This is the vendor website for the Drive and Driven Gears. Go about 2/3rd down the page to the TH350 section. PATC sells the Drive and Driven Gears.

I don't know what length cable you will need.

Thanks lugnutz the flaps here in town cannot seem to answer the question and do not know whom to call. I have talked to a few transmission shops whom seem to be lost too.

At least its a start. I will research it further tomorrow.

I just checked the tranny i have a red drive gear and a whitish 19 tooth driven gear the one that the speedometer cable goes into

I suggest you buy a 7 tooth drive gear and a 20 tooth driven gear. The drive gear is easy to exchange. You will need to remove the T5 from the truck and then remove the tail housing. PATC will give you good advice. Just verify that the rear is 3.90 before you proceed.

Gotcha i am down to motor tranny in a rolling chasis. I have called a local driveline company and if they do not have it i will order it from PATC. Yes i have verified the 3.90. I will update the progress

I called PATC they just informed me the 7 tooth drive gear and the 20 tooth driven gear was no longer available for the GM model of the T-5. They say they are not making any of those gear (driven or drive for the speedos on the GM T-5)

Does anyone have a source for these? With or Without part numbers or with or without prices.

What about a source with p/n for the jeep input shaft?

I have my tranny on the bench.

Found them new on ebay.