I noticed on the freeway this morning that my speedometer is freaking out a little bit. It will just jump around within about 5-10 mph of how fast I am going. For example, I am cruising at 70, the thing will just flick down to 65 for a split second, and then come back to 70. It was doing this ever 10 or 15 seconds. Once I got off the freeway, it seemed to stop. Any clues?

 

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Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Thats it for now, saving for a stang. Check out my Gallery for a look-see.


Justin

 

Well, I just got the rear-end rebuilt after it grenaded on me. Is it possible that the shop missed some damage to the exciter ring, or didn't get the VSS hooked back up correctly?

 

You might want to check the gear at the end of the speedo cable that plugs into the tranny. When I had my tranny rebuilt last year, I had the same problem. It turned out that the gear was completely worn out. And the trany shop didn't check it or replace it. Having the rear-end rebuilt should not have caused this problem.
Hope this helps.
Kimball

 

my spedometer jumps around while i am about 0-35 when i get in the higher speeds it stays at one speed. is mine the same as this? should i replace the cable or everything? i think my cable goes into my transfer case <not sure, only looked real quick> and i have a lot of slop in there, could that be the problem??? i don't need a ticket.
Andy

 

Hey, Kimball, what year is your Bronco? I don't believe my '96 has a speedometer cable. Instead it has the VSS on the rear differential, and an exciter ring in the differential itself.

 

Hey, Matthew
I have a '90 with the 5.8L(351W) and the E4OD Tranny.

The '93 to '96 Bronco's have four wheel ABS. That exciter ring inside the differential, I'm assuming that you have the 8.8 rear-end, is accually for the ABS. That connection on the housing of the differential is most likely the ABS sensor, which is accually a magnetic pick up that counts the teeth on that ring inside the differential.
I had to double check with my manual as I'm writing this. Your speedometer is accually an electrical one. So the speed signal is picked up from the rear anti-lock brake sensor. The '92 and later have this setup. The '91 and older have an accual mechanical speedometer cable. Which is what I have on mine, epxlained below.

I have a spare engine(5.0), tranny(AOD), and transfer case from an '89 bronco, that I just checked both to make sure. On mine the speedometer cable accually plugs into the transfer case just before the rear drive shaft. It also has an electrical connection. Only a few of the teeth on the gear at end of speedometer cable that slips into the casing were worn out. Which gave me an inacurate speed rating at any speed. The speedometer bounced around within 5 to 10 miles of what I was accually doing.

On your '96, you might want to double check that connector on the differential. It could be possible that the shop that rebuilt the rear-end may not have put that connector back in properly. Or worse off, forgot the exciter ring(or damaged it). If you feel like getting a little messy, try to take the cover off the rear-end to check that exciter ring to see if it is in good shape, which is mounted behind the ring gear.
Hope this helps
Kimball