Speedometer Problem 95

[zippyluke]

Hi,

I am having problems with my speedo. It started bouncing alot lately, and then the tranny started shifting really rough. So I took it to a transmission shop, and they replaced the speed sensor. That seemed to take care of the tranny problems, but the speedo is still bouncing. I tried to change the instrument cluster, but that didn't correct the problem. What can I check next? I am not very mechanically savvy, but I can follow direction great. How do I check anything else? Any help would be much apreciated.

Thanks,
Luke

 

[BrooklynBay]

Welcome to this forum! Check the wiring in the steering column for pierced insulation around the area of the tilt mechanism. Does your cruise control fail when this problem occurs?

 

[zippyluke]

Speedometer

Hi, the cruise control is not working now. It seems to turn on, but it accelerates and decelerates according to what the speedometer is saying. How do I check the wiring?

 

[Cobraguy]

This sounds like your speedo and cruise are still getting an erratic speed signal. I don't believe though there are any wires for that going through the steering column. Possibly Brooklyn knows something I don't. But if I recall, the 95 model doesn't distribute VSS from the ABS module like newer models do. I wonder why the new VSS fixed the trans, but nothing else? I think it's time to get out the wiring diagram and start tracing your signal. As Brooklyn mentions, you might have a wiring issue somewhere.

 

[zippyluke]

I will try and do that, but I'm unsure how to 'test' wiring. Where can I get a wiring diagram? Can anyone help me with some simple istructions how to go about testing. Thanks.

 

[BrooklynBay]

The tilt columns have been known to pull on wiring, and eventually pierce insulation. This will cause intermittent ground signals which will lead to a fluctuation. This problem was once outlined in an issue of Gears Magazine on an Econoline 350 motorhome. In that case, the problem started with road vibration while driving on the highway. The speed sensor was changed, and didn't solve the problem either.

 

[pj8847]

Not sure if this is a 4x4, but if it is, you might want to check the rear output of the t-case for play. Excessive wear in the rear case and/or bearing will cause the output shaft to move enough to allow the mesh of the VSS gear to be thrown off and skip (I've been living with the problem for some time now). Same would apply to a 2 wheel drive, just check the output shaft coming out of the tranny for play.

When the Vss was out, was the gear on the end inspected carefully for cracks and wear? If not, pull it out and check. Every time I chew a gear on my VSS (*explained below), even if it's just one tooth, I'll get the "bounce" in the spedo and the CC will act just as you describe. Sometimes the gear looks good, but the teeth, when inspected closer, will bend out of the way showing the break running the length of the tooth, resulting in the failure being missed by most. Normal wear and tear could be the culprit also, since it is a '95, and the gears are plastic...

*(My t-case rear half is bad, to much play around the bearing, been looking for a good one, but they are getting harder to find as the truck and it's parts age. I refuse to buy a "new" one, and the "reman" alternative isn't worth the cost just for a bushing and sleeve being installed...)