Speedo drive gear demolished!

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scott2683

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So I posted on here a couple weeks ago about having my 4 speed rebuilt. I got my car back last night, test drove it, and it's a lot better, however I still have a vibration somewhere. The new clutch felt amazing once I removed my over center spring, and the car actually feels faster.

So I decided to take a little evening cruise last night after getting it back, I didn't hammer on the car just a little spirited driving. I went about 15 miles, and come up to a stoplight. When I go to take off I notice the speedometer isn't working. I checked the cable, it was good so I pulled the drive gear out, and it was absolutely demolished.

I'm going to order a replacement, how can I prevent this from happening again? What caused it to happen this time? Any tricks on reinstalling it?

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speedo gear housing, has to be clocked to the proper gear tooth count position.
clean/ look at the housing you will see gear count numbers
 
It could have been installed (clocked) incorrectly. Don't know if there are any other potential reasons.
Was it a 34?
 
Better check the gear on the tailshaft of the transmission now. It may not look much better than the driven gear you pictured. You have to line the housing up with the proper notch for the gear tooth number. I have a picture somewhere. Disconnect the cable and spin it to make sure it's not binding.
 
Yeah it was a 34. So according to this diagram, I need to make sure that 32-38 is in the 6 O'clock position since the gear was between those specs?

I've checked the teeth on the output shaft, and everything seems to be fine. I just don't see how that happened?
 
Yeah it was a 34. So according to this diagram, I need to make sure that 32-38 is in the 6 O'clock position since the gear was between those specs?

I've checked the teeth on the output shaft, and everything seems to be fine. I just don't see how that happened?
Yep
 
Hey guys, I need a little more help. I ordered a new drive gear, I put it in, and clocked it correctly based on the image above and the other research I've done. I took the car 5 miles down the road and it ate the teeth up again. The speedometer didn't bounce, there was no sign of it not working correctly. I have no idea what I need to do to stop this from happening again. I never had an issue until I had the transmission rebuilt.
 
I was about to say a very powerful engine will eat gears up. Racers don't use a gear & block off the spot.

If this is not the case, I think a talk to the rebuilder is in order.
 
Th
Hey guys, I need a little more help. I ordered a new drive gear, I put it in, and clocked it correctly based on the image above and the other research I've done. I took the car 5 miles down the road and it ate the teeth up again. The speedometer didn't bounce, there was no sign of it not working correctly. I have no idea what I need to do to stop this from happening again. I never had an issue until I had the transmission rebuilt.
they shimmed the trans wrong, go *****!
 
I was about to say a very powerful engine will eat gears up. Racers don't use a gear & block off the spot.

If this is not the case, I think a talk to the rebuilder is in order.
It's not a powerful engine, it's just a mild 360. I've already contacted the guy that rebuilt the transmission, and he's going to look at it monday morning. I just can't visualize what's causing this transmission to eat a plastic gear within 5 miles.
 
Wrong spacers in the wrong spot I aint a tranny guy so those that are pipe up. Never saw one of them ate up before has to be out of position!
 
I'd say the gears and everything are probably fine, I've only put a few miles on the car, and it doesn't make any weird noises and it shifts just fine.
 
If the cable was binding, it would twist the square end off of the cable down by the trans.
I installed a new Classic dash and Autometer gauges. The adapter supplied to screw on the back of the speedo was binding the spinning internals of the Autometer gauge. Twisted off two cable ends before I found the problem. Classic dash verified the problem, remachined the adapters. I pulled the speedo gear to verify it was not damaged (43 tooth gear). Gear was ok.
 
I ended up buying a new speedo cable for it, and a new gear. I carefully clocked it and haven't had any problems since. Hopefully that's the last time I have to deal with that issue!
 
I was looking at the housing it is on an eccentric, it makes sense that if it wasnt in correctly it would grind itself up. Incorrect lash basically.
 
I was looking at the housing it is on an eccentric, it makes sense that if it wasnt in correctly it would grind itself up. Incorrect lash basically.
Yeah I'm sure thats what happened. It's put in correctly now, which is good ...considering those gears are not cheap! LOL
 
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