Weird Odometer/Speedometer Issue

[Optimus Joe]

I checked the board and have not seen this issue brought up before and am looking for some help.

When I first picked this '96 Sport up, the odometer quit working. If figured the gear had rotted out and put it on my list of things to fix. Then, I noticed it started working, but would stop. After monitoring it for awhile, I see that it will work up till about 35 - 40 MPH and then both the trip odometer and the odometer stop working. They do not work when I slow down or stop. That said, if I park the car and leave it off for awhile and then drive it again, they work again until I go over that speed limit.

I found today, that they also quit working if I have to floor it, even if I go under the above mentioned speed limit, if I have to floor it to make a light or some such thing, they quit working.

Then, the other evening, I was driving and the speedometer went to 0, quit working for a bit and then started working again. It then went to 0 and quit working for the rest of the drive. No ABS light came on and the Cruise Control still worked.

I am not sure where to even start with this. Any ideas?

Thanks in advance

 

[EB4X]

Sounds like issue with VSS.
Or.....on my failing odometer I didn't notice any variable on speed affecting it's functionality but it would occasionally "kick in" and then shortly stop working again..pretty much same scenario. That being said it WAS the worm gear failing....it had enough teeth/ partial teeth to occasionally grab/ (with resistance from built up muck as well) to work sporadically. Replaced and odometer is 100% functioning. Here's the links you need - read my bottom posts on my thread.... also, while you have instrument cluster out I would replace all your bulbs.... might want to put in brighter LED versions too.
(If you have auto trans take extra note of second link/my thread --- I address shift indicator needle alignment ISSUE as well. )
Odometer Worm Gear Replacement

HELP! Started disassebling instrument panel and shift indicator disconnected

 

[CDW6212R]

If the transmission functions properly all of the time, no issues, than the problem should be in the dash/cluster. The VSS is required for the transmission, so if the trans is affected, the problem is serious and needs attention now.

 

[Optimus Joe]

If the transmission functions properly all of the time, no issues, than the problem should be in the dash/cluster. The VSS is required for the transmission, so if the trans is affected, the problem is serious and needs attention now.

Well, the tachometer has not given me any problems, so based upon what you are saying it is a cluster issue, correct?

I have heard some people mention a part near the transmission, the speed sensor, that impacts the speed and the odometer. Is there a way to rule out that it is one over another.

 

[CDW6212R]

I said the transmission, not the tach. That's because of the speed sensor, which is the VSS, which is the rear ABS sensor, which is on the rear diff. That sensor rarely ever fails.

But any VSS problem should affect the transmission, so if your trans is not acting up, then the odometer issue is probably in the cluster. The speedometer and odometer have a circuit board, and mechanical parts, gears etc. Either can go bad, at this age it's going to be more likely than ten years ago. Those are all fragile parts, go easy with them if you have to work on them.