My speedometer needle moves almost constantly 5-10 mph off actual speed. I've replaced the speedometer gear (made sure it got back in the correct position) replaced the ratio adapter and speed sensor and the dang thing still dances. (No speedo cable....wire from the sensor to the speedometer) The trans output shaft worm gear sleeve appears in good shape but hard to really tell with a flashlight and my finger (I can move the gear sleeve on the shaft with a little resistance) Any ideas? I'm stumped......

And what's with my water temp gage moving in concert with my blinkers??..and moving even further toward hot when I turn the lights on or A/C???.....Alternator output is 13-14 amps at idle. Help.

 

Sounds like you may want to check the voltage regulator. All my gauges started dancing when it began going out. Not sure though.

 

Check all your grounds first... bet thats your problem..
I dont remember who, but someone just posted recently that they corrected this by splicing into the speedo harness's ground wire and grounding it directly to the cab..

 

mine used to do that. it was the spedo-cable. if all else fails check that.

 

Remove your driveshaft and tighten up the retaining nut (I assume since you can turn the gear that you have a 2wd). It takes like 350 or so ft-lbs torque. I put red loctite on mine and got after it with a 3ft cheater pipe on the end of the breaker bar. That SHOULD fix your speedo.

As for your other electrical gremlins, I'd agree on the grounds. Bad bulb can also wreak havoc on stuff.

Daniel

 

Watching this post..... Some of my gauges jump in concert with the turn signals.

 

Generallly that is a bad ground somewhere in the circuit. The dash gauges and lights all share a common ground, and if there is a poor connection, they can "bleed over" onto each other so to speak. I am not sure which wire it is coming from teh large round plug , I beleive they changed from one year to the next ...

 

That was me. I spliced into the ground wire at the sensor, and grounded to the cab. It does still jump around over 50 mph, but I havent had the chance to do a good ground to it yet. It was done on a spur of the moment thing to see if it would help.

Before I did this, it was jumping around all over the place, I would be going 15 mph and it was saying 70mph. I also installed a new speed sensor before I did this, so that wasnt the fix.

There must be a ground somewhere in the system that isnt right, but I dont know where that is.