What would cause a speedo gear to wear out in 1 day?? (1 Viewer)

[mark248am]

Hey guys I have a bizarre problem.

The needle on my speedometer was bouncing for a few weeks while driving, it would tell the speed but kept bouncing while doing so, and then it eventually stopped working. When I pulled out the speedo gear from under the car I found it to be worn out. No biggie, ordered a new one and replaced it. The speedometer started working again but the needle was still bouncy, I figured it was probably an issue with the cable. A day later, the speedometer stopped working again!

Does anyone know what could possibly be causing my speedo gear to wear out in under 24 hours? My theory is maybe the cable is old and super dry causing so much friction with the speedo gear that it doesn't spin as freely causing the metal gear to grind it? No idea if that's possible but it's the only theory I have.

I have a new cable to swap out with, but the guys who restored my car welded or glued the cable behind the cluster and I can't pull it out to replace it. You can see some grey stuff in the photo below, I think its glue. I'm worried if I force it out harder than I'm already trying to remove it I might damage my cluster and don't have $300 right now to spend on a new one.

 

[mattressking]

Wrong combination shreds the gear that way. That looks like metal not glue/rtv. You’ll need to remove the cable and pull it out. Try to use needle nose to rotate and remove from cluster.

Pull the rear flange off tcase and read speedo drive gear ratio. Then match driven gear to that and replace the speedo cable.

 

[pb4ugo]

That's strange. The inner cable shouldnt be stuck into the back of the gauge. You should be able you pull the inner cable out of the sheath thru the other end. You should be able to lubricate/grease it and reinstall. It sometimes fixes the bouncyness.

 

[clrussell]

That's strange. The inner cable shouldnt be stuck into the back of the gauge. You should be able you pull the inner cable out of the sheath thru the other end. You should be able to lubricate/grease it and reinstall. It sometimes fixes the bouncyness.

My logic says this might fix both problems.

If the cable is tight in the sheath then it’ll bind causing the bounce, also would cause excessive wear on the plastic gear

 

[pb4ugo]

Maybe, it could be a mesh problem too, or both.

 

[clrussell]

Agree

 

[mark248am]

Wrong combination shreds the gear that way. That looks like metal not glue/rtv. You’ll need to remove the cable and pull it out. Try to use needle nose to rotate and remove from cluster.

Pull the rear flange off tcase and read speedo drive gear ratio. Then match driven gear to that and replace the speedo cable.

interesting, i thought the different gears were for different tire sizes. The gear I pulled out originally was a 1x16 so got another 1x16 in its place. Not sure what the rear flange is or if its easy to pull but I'll google it now and try to figure it out.

 

[mark248am]

Maybe, it could be a mesh problem too, or both.

Mesh problem? Whats that?

 

[mark248am]

That's strange. The inner cable shouldnt be stuck into the back of the gauge. You should be able you pull the inner cable out of the sheath thru the other end. You should be able to lubricate/grease it and reinstall. It sometimes fixes the bouncyness.

Yeah it shouldn't, no idea why they stuck it in. I tried pulling it out as hard as I could and it wouldn't budge. Its ridiculous.

 

[pb4ugo]

Mesh problem? Whats that?

That plastic gear is driven by a gear inside of the tcase housing. As @mattressking mentioned in his post.

 

[mark248am]

That plastic gear is driven by a gear inside of the tcase housing. As @mattressking mentioned in his post.

oh, I don't even want to venture there I'm really hoping its just a messed up cable, but knowing my luck nothing ever is a simple fix

 

[mattressking]

oh, I don't even want to venture there I'm really hoping its just a messed up cable, but knowing my luck nothing ever is a simple fix

Suck it up, it’s just nuts and bolts

 

[mark248am]

Just wanted to update this post in case anyone searching had a similar issue as me. So this is what happened since my last update.

I replaced the speedo gear with one thats 1x17. Also ordered a new 1x16 as a backup.
I then replaced the cable with what I think is a replica cable and not OEM. It was given to me by the shop that restored my car and I decided to fit it.

After swapping both parts I drove for a bit and I ran into the same issue, speedo would work and then eventually fail 30 mins or less later.

I was feeling disappointed but then when I was driving slower in a quiet neighborhood I could hear something behind the dash making a sound as if the cable was rotating with the car as I'm driving. So I figured speedo gear and cable are fine but the dash is what's broken.

So I ordered a new OEM dash. When it arrived I pulled out the old dash and tried installing new dash and then a small metal bit fell. Turns out the thin metal piece inside the cable had broken where it fits into the back of the dash.

So had to wait and order a new OEM speedo cable and just finally got around to installing it today.

Drove the car for around 35km and so far the speed in the dash is working. It's off by around 15km, so at 100km/h it's actually around 85km/h but that isn't a big deal obviously and most likely has to do with the 1x17 gear I installed in place of the 1x16. Looks like what was causing all my issues was the old dash.

So new gear, cable and dash. If issue comes back, I give up.

 

[mark248am]

noooooooooooooooo my speedo stopped working again. This time it survived nearly 400 miles, I thought the issue was fixed! Could be because I used the 1x17 gear instead of 1x16. Luckily have a brand new 1x16 so will swap out and try one more time.