Speedometer is fast

[Kerben]

Hi, I'm new to TDR and new to cummins. I just picked up a 93 first gen and I couldn't be happier. The only real issue I have is the speedometer. It works every once in awhile and when it does, it's anywhere from 15 to 30 mph too fast. I'm thinking it's some kind of speed sensor that is messing up, but not too sure. Anybody have any idea? Thanks.

 

[DVolk]

change out the speed generator its screwed onto the transmission or tcase if a 4wd truck my guess its going bad

 

[Bob Beauchaine]

First of all welcome to the TDR - good to have you aboard!



It will help us to help you if you fill our your 'sig. '. Does your truck have a G360 manual trans or a 518 auto transmission? There are some different issues associated with both types.



Bob

 

[Kerben]

It's a 93 4x2, manual trans, extended cab, flat bed dually. That's about all I know about this truck. Hope that helps.



Karl

 

[Bob Beauchaine]

The exact same truck as mine.



These trucks with the manual trans. had a different simtom that could cause the problems that you describe. The drive gear on the getrag that drives the VSS is held in place by a jamb sleve on either side of it, these sleves are the only thing that keeps the gear from moving. What you will have to do is drop the drive line at the back of the transmission - they used "U" clips to hold the "U" joints on both the front and rear of the drive shaft on manual 1st gen trannys. Once you drop the driveline, at the transmission only, you will see a large nut - I don't remember the size - that nut has to be torqued to 290 lbft of torque to keep the drive dear from moving inside the transmission. This will cause the exact problems you are having. I've seen cases where as little as a 1/8 to 1/16 of an inch or less of nut movement will keep the gear from moving.



Since this is a free potential fix I would use this first. If this does not help I would then try DVolk suggestion.



BTW this was first noticed on 4X4s but applies to 4X2s also - there was a TSB out at one time on this.



Good luck



Bob

 

[Kerben]

Thanks, bob. I'll get under there and check it out as soon as I get a chance.

Karl

 

[Bob Beauchaine]

Karl



One more thing comes to mind. If when you get under there things, as far as the trans mounting is concerned are not as I described, you do not have a Getrag you probably have an NV4500HD. The NV was not an option but rather an after market setup. If so there are other solutions available.



Bob

 

[DVolk]

On one truck i got when i got it it didnt work the spline was striped out and it did not work replaced the transmission peice and worked fine , you might also check for a pinched wire my guess its just bad or dirty

 

[Kerben]

I was looking for a "speed sensor" or "speed generator", but all I can find is a three wire speed sensors and the one on my truck only has two wires. Anybody know about these things?

 

[DVolk]

I think one is a ground if the plug is the same , it should work

 

[Greenleaf]

No... . that sounds right. I have and have had many Dodge vehicles over the years and that is what they are..... well off!!



I can confirm this via roadside radar units and GPS. All mine read really FAST.



The NEON ,1990, 1992 rams and the Durango are all well off. This would seem normal. You are good to go.