1995 Speedometer Bounce

[bharris]

I have a 1995 Eddie Bauer and at times when I reach between 50 and 60 MPH, the speedometer needle will bounce as much as 5-10 MPH. This doesn't happen on a consistent basis. I have changed the speed sensors in the transmission and in the differential and put in a used instrument panel which checked ok by the parts dealer. The unit is electronic so there is no cable like on earlier models.

The wiring harnesses all look good so this thing is driving me crazy.

 

[Billy177]

hook up a scanner to see if it is an gauge problem or with the sensors themselves

 

[DasFrem]

The 95 reads straight off the transmission, I had the same problem only more dramatic. It started out small but then it would bounce all over the place all the time. The worst was that it would kick in the speed governor at random times, usually while accelerating onto a highway. Speed governors are no fun when you’re under hard acceleration into busy traffic in a lifted truck. I had replaced the speed gear to compensate for the gears/tires combo I had put in but I had not tightened the speed sensor all the way in so it stripped the plastic gears on the speed sensor and in the transmission. I've replaced the gear on the sensor 3 times (I had some spares laying around) and all 3 wore out within a week, so now I just keep it disconnected since I don't want to bother taking the trans apart to get at the gear inside. I use my GPS for speed now since it's much easier than dropping the tranny to get at the gear inside.

 

[bharris]

Thanks for the tips so far. I had the transmission serviced recently and the ring and pinion gears replaced at the same time and had the dealer check the VSS in each unit and they came back fine. I don't have a scanner, so I guess it's back to the dealer and pay the robbery diagnostic fees.

 

[ohfugit]

When this was happening on my 93 replacing the speed sensor fixed it.


some of the other troubleshooting bullet points were
check the speedo cable for binding
gauges
gears at the end of the speedo sensor as well as another.
Pretty sure the sensor was something like 19 bucks at murrays.
Also someone mentioned its different on the newer trucks

Does your cruise control work erratically and seem to follow the speedometer behaviour ? mine did
"D"

 

[bharris]

Thanks. The 95 does not have a cable, so the only thing I haven't changed is the plastic gear on the speed sensor. I guess I'll try that and if it doesn't fix it, I'll have to break down and get robbed by the dealer