I have a 91.5 12v 4 speed auto. The other day the speedo quit and it stopped shifting into overdrive. I have read around and to now know where my speed sensor is located

 

Speed sensor is on the tailshaft of the transmission or transfercase tailshaft. It should have 2 wires going to a plug.

 

Thank you. I couldn't find anything anywhere. Just people saying that's would be the most likely thing to go out

 

Believe it's at your transfere case (TC). I've got a A518 Auto trans ('93 W250, 6BT, Intercooled Motor). The speedo measuring pick-up reqs the 90 deg bend formed by the Trans to TC Adapter hook-up to be in the 3 O'Clock psn (Pt. of Ref - Looking at hold down nut of assy to TC.) Make sure elec. 2-prong connection is clean & dry. I've had the same problem. Hope this helps. winston

 

Last time I had that problem on my 91.5 W250, the speedo cable from the gear box to the speed sensor had wallowed out and would let it just jump around inside the what once was the square drive that turned roundish...

 

That's what I'm thinking it is. I replaced the speed sensor first because it's was like $14. But it didn't fix the problem.

 

I'm glad my speed sensor pick-up worked w/ a simple rotation - Tearing down the TC to fix a wallowed-out square drive sounds menacing. Check-out other 1st Gen posts to fix before removing and TC, tear-down, and replacing a square drive. I think I got the info regarding positioning of the pick-up from a transmission expert or the old manual concerning R&R Labor time assoc w/the A518 trans. Good Luck!

 

I can't get anything to work. I replaced everything on the transmission and still no go. I put a drill in the vss and no getting anything. Could the gear on the speedo be done for

 

I've got a '93, W250, 5.9L, Turbo Diesel/Intercooled Motor w/ A518 Trans; the speed sensor comes off of the Transfere Case (TC) on my rig. All info I've sent you is based upon my experience alone. Don't know what you mean by "replaced everything on the trans"? My speed sensor pick-up comes off my TC via a 90 degree reducer? Since the pick-up is optical/electric, you may have a wiring problem from the sensor PU to the PCM/Speedo. All I can say is check continuity in you wiring. Again, Good Luck RichdOrtiz.

 

How about a picture of what you think is everything in reference to your speed sensor on the transfer case?

 

It ended up being the computer. All the terminals were gone.

 

What do you mean by the terminals were gone? Where did they go to, or what happened to them?

 

Moved to 1st Gen Forum

 

Find the pinout on the wiring harness ECM plug and run it ground for the speedo to work.

You can do the same thing on the appropriate pin out for the OD to work.