Cruise Control Problems

[Six_Man_Diesel]

Buddy of mine has a 92 model, and his cruise works, but it fluxuates back and forth from fast to slow in about a7 mph range. Has anyone heard of this problem before??

 

[Bob Beauchaine]

If he has the Getrag transmission I my have a possible solution. When you remove the driveline from the back of the transmission you will see a nut holding the output shaft to the back of the transmission. This nut serves also serves as a "jamb" nut and keeps the speedometer drive gear from moving. This is the only thing that keeps it from moving. When it is loose - as in less than 1/4 of a turn this drive gear can slip causing the problem your friend may have. I don't remember the torque but it is high 250 to 300 ft lbs. If he does have the Getrag let me know and I will look up the torque in my shop manual.

Mine acted the same way while still under warranty so Dodge solved this one for me. Good luck.

Happy trails

Bob

 

[Six_Man_Diesel]

Thanks alot Bob. His speedometer reads out just fine, it doesn't fluxuate at all. But when you have the cruise on, the actual speed of the truck goes fast to slow fast to slow, in about a 7 mph range, this sounds like what yours was doing huh?? It is a Getrag.

 

[Paychk]

There is a service bulletin on speed control Over/Undershoot your dealer can print it out for you, the number is 081695A. The fix is to reprogram the cruise control module; by setting the cruise control while holding the speed of the truck constant, wait 10 seconds and shut of the cruise manually, repeat 10 - 15 cycles - Hold, set, 10 seconds, turn off. What the control does is adjust or learn the amount of slack in the cruise control throttle cable. If you set the control speed without holding the speed constant then the control learns to adjust incorrectly and you end up with the Over/Undershooting.



Hope this helps

 

[Bob Beauchaine]

It sounds like paychk is closer than I am. My speedo fluctuated also. When I worked in the dealership my "cruise control" expert said that the 1st gen. cruise controls were adjustable and that the 2nd gen had a "learn" mode. I have a shop manual for my '93 and can look up what it says if paychk's advice doesn't work. Good luck

Happy trails

Bob

 

[Six_Man_Diesel]

Thanks alot guys, I'll pass on the procedure to him and keep yall informed.