speedometer problem on a 93 legacy

Dog Trainer · 08-15-2006, 05:53 PM

I recently purchased a 93 Legacy this is a Cummins DP on a spartan Chasis. I have aproblem with the speedo that I knew about going into the deal.when you start the motor and at idle, the spedo needle jumps up to about 45 and then back down again. When driving it jumps and says aboy 75 when you are going about 45-50. Bottom line is something is not right. I remember that in the past a jumping speedometer ment that a cable was about ready to break. But with the jump at idle and not in gear I suspect it is something more like a ground or other electrical malfunction. Has anyone else experienced this problem?

overlander63 · 08-15-2006, 07:31 PM

You may have a bad wire going to the sensor, or the sensor is in the process of crapping out. Does the coach have ABS? I am guessing it has an Allison transmission. On some coaches of that year, there is a two-prong plug under the hood that goes to the speedometer, it may have corroded or gotten loose over time. Please let us have some more info, we can try to send you in a direction (hopefully the right one).

Dog Trainer · 08-15-2006, 08:50 PM

Thanks for your reply Overlander63. It does have an Allison Transmission and air brakes. This coach only has 35,000 on it so it has sat around a lot. Is the sensor on the transmission ? I know they used to be on the front wheel. The owner says the speedo was working fine but this coach had not been driven since oct 05 and then sat 3/05- 10/05. I know I need to go through it completely and change filters, fluids etc... before any miles are put on it.

overlander63 · 08-19-2006, 05:21 PM

The sensor may be at the rear of the transmission, or a part of the ABS (wheel speed sensor).