Speedo working on and off

[youngmanvr4]

First off my speedometer works on and off...mostly off though lol. I have done some searching and I know about replacing the speed sensor, checking wires/connections, fuses (though I know its not fuses becuase it works on and off). I'm in Texas right now and the car is in Kansas but I will be going back to pick it up at the first of the year. Would like to have a speedo for the 1,000 mile trip.

Now for the story of when it started.My transmission went out so I bought a used transmission from a local guy. When I was swapping trannys I took the speed sensor off of my old transmission and put it on the transmission that was going in. Before the swap the speedo had worked fine. Never had a problem. Finished the transmission swap and now the speedo doesn't work. Like I said before the swap it worked, finished the swap and now it works on and off. I checked and cleaned the wires and connections under the car, didn't fix it.

So I've came to one of a couple things.

1) During the swap the sensor got damaged and is only working on and off.

2) The speedometer gear inside of the transmission is worn down and only catchs some of the time.

3) Not enough oil in the transmission and the gear only moves sometimes. Which I filled the transmission up the the fill plug on flat, level ground, so I doubt its that but just a though.

4) The speedometer itself went bad out of no where. Note that in lights up, just doesn't move most of the time.

I would say its the sensor but the thing that makes me question it is that it worked fine before the transmission swap, and now after it doesn't. Thats what makes me think it could be the speedo gear inside the transmission itself. But I hope its the sensor becuase I dont want to have to do anyother transmission swap.

When I doesn't work it just stays at 0. Sometimes it jumps from 0 to XX (whatever speed I'm going) and just bounces like a mad man. And sometimes, rarely, it will actually work right....for a little bit at least. Over all I have the gear x rpm =speed figured out but I need to have the speedo going. I dont like relying on rpm to know my speed plus I dont know if its 100% correct, but it works for now.

So if someone could help me out and give input that about be great. Thanks.

[180fan]

Had this problem on my Altima. Have you checked the actual connector from the speed sensor? It could have stuff like gear oil on it or the connection might not be tight enough. Check over that for the obvious reasons. Post back if you're still having problems.

[meangreens14]

mine does the same thing and i have found it to be the connector up near the engine bay. that little sucker just keeps coming loose. but also my speedo has never read at the correct speed, it's like 30 mph under or something like that. but for your case, keep checking the wires, its very rare that the sensor it self goes out. and the oils should not have anything to do with rotation or no rotation.

[youngmanvr4]

Yea I checked and cleaned the connection for the speed sensor up towards the engine bay. Then electric taped the thing like crazy to insure it would come lose or get any more crud in it.

I'll take the tape off and clean it again. Maybe I didn't get it clean enough? If its not that then what should I do next?

[youngmanvr4]

Bump for more help.

Also I was researching every thread I could find on speed sensors, speedo not working and ect. and found a thread where a guy was having the same problem as me, replaced the actual speedometer (in the cluster) and it fixed it. I'm almost thinking its either the actual speedometer in the cluster or crud still in the connection for the speed sensor or the speed sensor its self.

Good news is I have a extra cluster some where. Just need to find it. Only question is, my car is a 90 with a DOHC swap, I did all the wiring right and everything was working. I then later bought a DOHC cluster and put the tach from it in the original SOHC cluster in the car. The tach worked and so did the speedo. Then a couple months later, now my speedo doesn't work so if I can find that cluster will it work if I put the DOHC speedo in my cluster? The SOHC speedo is currently whats in it and its what worked fine before. I cant see why the DOHC speedo wouldn't work since everything else is DOHC (transmission, engine, ecu). Shouldn't it work?