my truck is a 91 350 jus bought it my speedometer and odometer is out some people tell me the cluster and some tell me the speed sensor on trans. Thought maybe some one could give me some advice. I am new to this deal but there is alot of good info on anything you need to know i reckon!!

 

oh i had this same problem, is your truck 4x4? or 4x2? if it's 4x4 the speed sensor will be on the side of the transfercase on the drivers side. the plug may be loose/fallin out. or the gear assembly where the wires plug in may be faulty. on the 2 wheel drive i believe there should be something similar on the transmission

 

It really could be either. I replaced the cluster in mine with one I had laying around, solved the problem. You can also get replacement gears for inside the cluster. There are some threads about that on here, just do a search.

 

The VSS going out is a very common issue with these trucks and is very simple to diagnose and repair.
There are some articles in the "Stickey" that discribe what the parts are, where to find them, how to test them and replace them..

 

The most common problems are the VSS and the odo gears going bad. But it isn't unheard of for the cluster to be bad.

 

You need to let us know if it's 2 wheel drive or 4x4 as there are some differences in locations underneath. My 2 WD, the "D350" in my signature, has a speedo drive on the tranny. It connects to a tiny gearbox which changes the rotation speed, the "ratio drive". That connects to the VSS which responds to the rotation speed and generates the electrical signal that runs the speedo head. You can do a simple test of the speedo head by turning the hardware underneath with a drill, since the ratio drive and VSS are both shaft-driven. With your ignition on your speed needle and odo should respond. Oh and I believe welcome-to-the-forum is in order. You'll find lots of help and talent here.

 

thanks guys ! Its a 2wd , im not good with computers but im going to get sum pics of the truck asap