Speedometer/Transmission

[lesndes]

We have 1993 SR5 4Runner with a very unique problem . It has been going on (off and on) for almost a year. It has been worked on by three different mechanics.

What happens is this; the speedometer will start bouncing. It may bounce for a long while, but eventually it will quit. Once the speedometer quits it may run fine for a while. BUT once the Odometer/ trip meter quits (and it will) then the transmission will stop upshifting. (1st-2nd-3rd, etc) BUT it may start running right again.

WE HAVE CHANGED ONE SPEEDOMETER SENSOR (at the lower part of the Transmission) TWICE AND THE OTHER ONE ONCE. BOTH HAVE OEM PARTS. Also the mechanics have replaced some of the wiring and plugs to the sensors.

We have been told that the mechanics can’t help us unless the 4Runner will mess-up for them. Of course that hasn’t happened.. The last repair was the mechanic created a new plug for the sensor that is located on the topside of the transmission. It ran around 1600 miles before it started messing up.

One of the things we have learned is to reset the computer by disconnecting the battery for about an hour or so and it will usually run normal for a while.

Story of last trip: We had traveled about 150 miles from home and the 4Runner messed up, We disconnected the battery for about an hour before leaving for home. 30 miles into the trip the speedometer started bouncing. Then 60 miles into the trip the speedometer quit, but the odometer kept working. At about 120 miles in the trip all of it quit working. Stopped for a stop sign and the 4Runner wouldn’t shift out of 1st. We were going to drive it about 3 miles to park it, so we stopped several times to let traffic pass. All of a sudden it started shifting and the Odometer started working. About 10 miles later (right by the mechanic) the speedometer started working for a couple of miles then quit again. Now the 4Runner bounces every once in a while and we are not taking it too far from home.

One other thing that happened trip before last. The Odometer/trip meter started running backwards. We shut the 4Runner off and started it back and it has never done it again.

Any suggestions would be very helpful.

 

[KidVermicious]

Your truck is haunted. Get a priest to perform an excorcism.

No, seriously though, doesn't the 93 still have a mechanical speedo? If so, there's no way the rest of the transmission knows what the speedometer and odometer is doing, and there's no way for one to affect the other. And the speedo and odo are both tied to that mechanical cable at the back of the dash cluster - there's no way a problem with the transmission or speedo cable could cause the speedo to quit but not the odo.

 

[lesndes]

Thanks - I agree about calling a priest. We will double check and see if it has a speedo cable.

 

[crash813]

Yup, I have the bouncing speedo. Its fairly common from what I've seen. The ECU will use the speedo for various calculations. I assume the newer TCU's might as well but my older variant doesn't. You should actually get a CEL if the speedo is off too much or not even registering.

What I've notice is the bouncing has been there when the cable is not inserted far enough into the back of the speedo. I'm guessing when its twisting and binding(older rusted/non-lubbed cables), it causes the cable to shrink and pull out just enough to not turn the gears. I bought a new cable and had to remove the end piece and reglued it too short. Thats how I find this issue. My guess is older cables may be binding up so badly, they may pulled back even with the correct insertion distance, but thats only a hunch.

WHat I would do is disconnect the cable from the transfer case and put it in a drill. Run it at different speeds while someone watches the speedo. If its still happening, do ever buy that gear again. Next, I would pull the dash cluster and pull out the speedo and check it out. Not hard to do. You can also go down to a pick and pull and get a new cluster for next to nothing and swap out and see if problem is the same before cracking into the gears.

hope that helps a little.