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Ok, I finished installing a limited slip in the rear end of my 95 F150 2wd. When I took it for a test drive I noticed that the speedo needle bounces around a lot while trying to hold a steady speed (like 5-10 mph bounces). When it does this the RPM's stay the same and it doesn't really surge or anything, at least not that I can really tell.
First, is it ok to drive it like this til Monday? When I was taking the ring gear off my old case I bunged up the teeth on the tone ring a little, but I was told that ring is only for the RABS. My instructor told me that it was the VSS on the side of the tranny. Does this mean the actual sensor is going out and I need to unscrew it and replace it?
Basically I am looking for any sort of help right now. I have no idea what to do now and I need to know if it will hurt the truck, since this is my daily driver and I cant afford to have it out of commision for more than an afternoon or Sunday.
That is what I thought, but then what is the electrical connector on the side of the M5R2? Does this mean that I will have to tear the rear end apart and replace the tone ring? Or is there something else that I need to do first?
Also, is it ok to drive it like this til Monday when I can get it back on a lift at school and do whatever?
The one up forward below the shifter is you neutral safety switch. If you have a 4WD, there is one on the TransFer Case. The speed sensor on the earlier one's was attached to the speedometer cable above the crossmember.
Not sure, try pulling the VSS out, clean the end that goes in the rear end and the connector and see what happens. If you want, you can also try smoothing out the edges with a file, they may be giving off erratic signals due to the shape. Would be worth trying before tearing it all apart again.
Its a 5 spd manual, so I just run it by the sound of the engine. That is how I was taught to know when to shift is by the sound of the engine (how much load is on it). I can set the cruise and it will hold a constant speed (in real life) but the speedo still bounces, without the RPM's moving at all, just the speedo and it doesnt surge with the cruise on either.
My speedo does the same thing as Wicky's...it bounces 5-10 mph at all times once over 35. I dont even look at it any longer....I just watch my tach (I also have a 5 speed manual)
Also I should point out that the guage is also about 5-10 mph off/below the real speed (ever since I installed the 32's) wish I could fix this problem too.
The 95's have a speed sensor on the differential, and the speedometer is electric. It is owner adjustable for different gear ratios - do a forum search for adjusting the "calibration constant." The speedometer stores a fixed figure that tells it what speed to register based on the differential gear ratio and tire size.
As for the bouncing speedometer, it can be caused by crud on the VSS, or a faulty speedometer/odometer module. The 92-95 have issues with this when they get into higher mileage.
I have 90K on the clock and I just switched the case, I retained the ring gear and tone ring. I am going to try cleaning it monday and double checking what I can b4 I tear it apart. Would I still need to recalibrate the speedo?