First off, I just wanted to say thanks to everybody who contributed possible solutions to my previous posted problem. I have changed axle ratios in my 95 f-150 4x4 from 3.31 to 1 to 4.10 to 1. When I bought the truck, it had 33" tires on it which I have kept. Now my speedometer is fluctuating back and forth while driving. I'm assuming the speed sensor is reading incorrect data from the rear axle. Any other ideas? Thanks.

 

I thought the speedo read off the tranny not the rear end. Did the shop who installed your 4.10's change the speedo gear to compensate for the change? If they did it may not be installed properly.

Randy

 

maybe the speedometer gear is stripped or has missung teeth



John Floyd
South Mills,NC
'86 F150 2wd 300 6
Crane Cam 260/272
stock manifolds, w/ staight pipe

 

Does your ABS light come on as well? My 95 has the exact same problem, the speedo gear is chewed up, throwing metal into the sensor on the housing.

Les

 

To lallen; No, my ABS light has not come on, yet. I'm pulling the sensor this weekend to have a look. Halvey

 

I believe the speedo does read off the tranny, however there is a speed sensor in the rear axle housing that also has something to do with the ABS and cruise control systems.

 

I was told that the sensor in the rear did control some speedo function, but I am not sure about that now, as I did replace the sensor, which cured the ABS light problem for a few days, but it came back. I was told by the mechanic that did the job, that the speedo gear was worn, and metal was flaking off of it, which would cause the ABS sensor to act up.

Les

 

Lallen, I just got my truck off the rack from my buddy's shop and we found the problem to the "jumpy" speedo. When 4 wheel performance centers swapped my diff and gears, they damaged the "tone" ring which bolts to the diff carrier. The rear sensor detects each of these "teeth" on the tone ring to determine speed and anti lock braking info. Mine had 4 teeth chipped of mushroomed causing the problem. Hope this helps.

 

Yep, I will get that checked as well. My speedo has been doing this for a while now, but I figure it will be a matter of time before I get nailed for speeding. I have just been pushing my luck with it lately.

Les