What would cause a jumpy speedo in my 91.5? I started it up the other morning and just eased into it to go across the yard and the speedo jumped to 90...as I drive it gets better. Some times it will be off by ten or fifteen and go up fast and come down rather slow. I'm at a loss because before I can get home it quits. Thanks for the help.

 

senser in the tranny tailhousing Phil

here is some more info I dug up...........SChandler posted his fix

This should get you started:
1) Pull the plug off the distance sensor on the side of the transmission and spray it with some electrical contact cleaner and make sure the female prongs on the plug are round and fit the male side tightly. Also check the wiring from the sensor to the firewall, it goes near the exhaust and may be burned.
2) If that doesn't help, pull the 90* adapter to the side of the transmission (on a 2wd 5spd, not sure about 4wd or automatic) and make sure that the drive gear is not slipping. If it is, it won't drive the sensor and you won't have a signal to your speedometer. The 90* adapter is available from Dodge. I can't think of the proper name for it, if you need, I can look it up.
3) Try a new distance sensor (also available new from Dodge). BE CAREFUL WHEN TIGHTENING THIS DOWN! I have cracked two of them due to overtightening. You just want it tight enough that it doesn't move when the truck is running. Also, when installing the sensor, align it slightly right of where you want it to be (closer to the floorboard) as the final turn of the wrench will snug it into position. Don't try to turn it after tightening, this will break something (not sure what) loose in the sensor and it will fail after a few hundred miles.
Sorry about the length of the post, this is everything I've done to get mine right.

 

okay I'll check that out...it's actually dry out today.

 

i have a 91.5 4x4 auto cummins and i hit some railroad tracks the other day and now my speedo my odometer and overdrive do not work. please help im desperate

 

you check the wiring from the tranny yet?

 

yep couldnt find anything disconnected or loose. do you think it might be that sensor on the tail shaft. the tranny probably has only 3,000 miles on it. i know its not a mechanical problem cause it was fine until the tracks. and all three went out at same time.

 

dunno fer sure but all parts are cheap here................I would pull it and check the gears, if that aint it then maybe the sensor


Zepco Sales & Service Inc
508 North Central Expressway, Richardson, TX 75080
phone: (972) 690-1138

also look here

http://www.carradio.com/gears.html

 

thank you for your help sir, its much appreciated. when you said t pull it you meant the guage not the transmission right.

 

on the tailhousing of the tranny where the wires/cable go in............look in there

 

10-4 i will go check it out and see what the heck is goin on with this beast thanks again