Hey folks,

I posted this in the T100 section but I'm getting no traction and this isn't model specific.

Basic details - 97' T100 2.7L 5spd 2wd (Mechanical Speedo)

This thing is setup like most yotas with a simple mechanical speedo that eventually failed. Like most, I knew it was the speedo or the gear. It bounced a lot and finally went out, the odometer would record about a mile every 200 miles.

Removed speedo gear, it was worn and mishaped in certain parts. Figured that was the culprit. Tested it out of the transmission and sure enough speedo moved when spun. So the cable isn't broken.

Replaced speedo gear with factory unit, tested in same method prior to installing back into the transmission. Moved speedo needle again so reinstalled. So it works as it should when not installed.

Once installed, no movement on speedo. Double checked everything nothing out of place. So, I Removed the dash cluster and ran the truck on jackstands. The cable doesn't move on the cluster end.

Removed speedo gear and ran the truck in neutral, the interal gear is spinning just fine.

The issue at this point has to be the External speedo gear not engaging to the internal gear. I don't know why the part can only be installed one way, has one bolt holding it in place once seated yet the two are not working together.

Has anyone had something like this happen to them?

 

So I think I have it figured out.

The transmission is painted gray. It MUST be a rebuild. I took a closer look at the old speedo gear and the new one and they are a different size. Same length, same markings same everything but one is a few mm's wider and that is the old one.

I ordered the new part for my model year, maybe this rebuilt trans is from an older model with a different size speedo gear.

New one that doesn't work has an 11 - 29 marking on the cog, old one 11-27

So.. guess I have a transmission from an older model in my truck... anyone know how to find out what year?

 

Marlin Crawler has some descriptions of transmissions on his site and how to identify several of them. I am not sure if he has the T100s or 2 wheel drives on there, but it is worth a shot.

 

I know this is an old thread but it helped me solve my speedometer issue, which is very much appreciated after rebuilding my t-case and fixing a few other drivetrain issues. Thank you!

 

I'm having a similar issue how did you get it tot work

 

There are two sizes (diameters) of the plastic speedo gear for the gear-driven transfer cases. I bought a 17-tooth gear from Toyota that was supposed to work in my '85 truck and would have corrected my speedometer reading. But after it wouldn't spin the speedo cable/speedometer properly, I read this thread and figured out the diameter was smaller than the one I pulled out by just a few millimeters and that's why it didn't work. So I put the the 18-tooth gear it came with back in, even though it looked a bit worn it worked just fine.