Speedo no go

[DieselBuzz]

Talk about beating a dead horse. I believe that I can now take my gauge pod out in less than three minutes. My speedo has not been working, I replaced the VSS, checked the gear box driving the VSS and bought a "working" gauge off e-bay. Still, I just turn the ignition on and it reads 28-30 MPH w/o the odometer turning or the motor running. When I'm driving the needle will bounce from 30 to the pin and at times seems linked to the RPMs more than the speed I'm traveling. I've checked the three connections on the back, good ground, 12 volts and I guess the signal, which my crude volt meter can't read. I'm feeling it's the PCM but +/- $250 just to get the speedo function back kills me. Did I miss anything, or do I just have to swallow the PCM pill? Thanks.

 

[CircleS]

New guy here. My speedo is doing something similar, it will take spells where it will not work/bounce all over the gauge. I have found that a smack on the dash above the speedo always starts it back working, but I know that one day it will quit. I am curious as to what you find out.

 

[csnider]

I had similar problems. . I would exchange speed sensors PCM speedo,, but i would get temporary failures and my cruise would always go into acceleration. I finaly dissasembled and cleaned and retensioned the plug contacts that connect into the speed sensor. . Solved all my speedo cruise and odometer problems. . I'd say it's worth a shot to check into that

 

[DieselBuzz]

Thanks, I've tried beating the dash with no success. #@$%! I'll go and clean up the VSS connections. I've also read of the gears in the speedometer head missing teeth but my are fine. Thanks for the encouragement, I will continue the hunt and keep you posted.

 

[DieselBuzz]

I checked the connections to the VSS. Now I turn it on and it goes right to 30mph and doesn't move. I passed the wiring into the cab via the shift tower and spin the VSS and the needle jumps. Come to find out the shaft is broken from the little gear box going into the transfer case. Maybe that was why it was jumping around??

 

[csnider]

Hey Buzz,

if you need a ratio adapter , this place has them . . you might need to tell them your rear end gear numbers and a few other things to get the right one. the RA is the same for a auto or stick... .



727 Mopar Transmission from PATC

 

[Bob Beauchaine]

If you have a manual transmission do a search on this problem. I've posted a possible solution for manual trannys that will not work on auto trannys. If that does not work for you post in this thread and I will re-post what I found with mine.



Bob