Engine/Transmission (1998.5 - 2002) Bumming at 40 mph

[jerald brown]

Soon after I purchased this 99 dodge diesel with 66000 miles, now has 117000 miles I have noticed a buming between 38 and 42 mph. This is an extended cab with long bed. It feels like a out of round tire. I have replaced the tires and it is still doing it. I installed automatic balancers by centramatic. Also all front bearings have been replaced. I have inspected the drive shaft with no slack in the ujoints. Did not fine any slack in the carrier bearing. All tires are with in 1/8 in. of being round.

 

[Mundgyver]

How are your shocks

 

[jerald brown]

I have also replaced the shocks

 

[Brand-X]

I have a 99 with the same problem I have changed to 19. 5s it did not help???

 

[AMink]

Did they road force your tires when balanced? Could it be your drive shaft? Mine looks like it has weights on it. Maybe you threw one? If you figure it out, let us know. I have a mystery BMMM at varying speeds... over different surfaces... at different speeds. :{

 

[Mundgyver]

Just a thought here, but since you have checked shocks and bearing and such, I make the assumption that you have also checked the alignment. My thought is not the standard alignment, but of all four wheels and what your thrust alignment would be. Trust meaning is the back tracking on the front or could your rig have a very slight crab walk back to front if you know what I mean. If you had a slight crabbing going on with the rear, I would think that this might cause what you are describing with harmonic vibrations through the frame and such.



Just a WAG on my part, but I am curious.