Frank1976

Hello,
My Friend (boss) has a 1994 dodge ram, 3500 pick-up, automatic,
5.9 cummins, with approx. 240,000 km (canadian guy). Recently around 50 km/h with overdrive off , theres a shudder/vibration (in the cab). Same thing with overdrive on and at 80 km/h theres a shudder/vibration (felt in the cab).
This problem only occurs at these speeds . Theres a list of repairs that have been done. Any ideas would be greatly appreciated. Thanks.

RCW

If my calculations are correct the engine rpm's would be approximately equal at either speed. That would tend to rule out driveline, carrier bearing, and universal joint problems.

I would look to the simple items first. Check the motormounts for one that has let go and is making metal to metal contact, then check the exhaust system for binding.

If none of those are the problem, then I would focus my attention on the flex plate that holds the torque converter to the flywheel. There were a series of flexplates used by Dodge that cracked and would then get out of balance. If it is not the flexplate, then I would look to the converter or the transmission input shaft as having a problem. It is necessary to pull the transmission to check any of these issues, so when the transmission is out do a dial indicator run-out test on the transmission input shaft. Also, pay particular attention to the adaptor that bolts to the back of the engine and adapts it to fit the Dodge transmission, they will crack if one or more motormounts are broken and the rig is run that way for an extended period.

DieselDaze

Welcome to DTR.
May need a bit more information on what kind of vibration he's experiencing.
Could be:
1) tire/wheel balancing,
2) front drive shaft,
3) rear drive shaft,
4) wheel bearings,
5) indication of something in the trans acting up.
or,
any combination of the above.

Rich.

DieselDaze

Too slow, Looks like RCW beat me to it..


Rich

Frank1976

Just a little more info:

-the truck just came out from transmission shop, transmission overhauled,, the mechanic said that the input shaft was broken in two piece,,,first time he saw that. $1600
-the shudder/vibration was there even before it went in for service.
-complete front end work done (ball joints,track bar, tie-rods,damper shock,links,sway bushings,etc
-2 new front tires,,, noticed that the mechanic only balanced the 2 front tires, the rear (dually) tires were not balanced.
-fuel filter, air filter replaced.
-alignment

Thinking about maybe going to the dealer. More $$$.

ratsun

I hope that $1600 wasnt just for the new input shaft
Those speeds kind of equal the lock up of the converter (if it has a lockup converter) Where in Canada is he? Maybe someone here can recommend a good shop near him

Frank1976

We've been talking about this at my bosses shop. Will having 2 different threads patterns (2 front, 4 different in rear) cause a similar problem.

also I noticed that the 4 tires in the rear are not evenly worn,, the ones on the inside are 50% thread left,,, ones out are due for replacement,,, can this cause a shudder / vibration ???
Thanks for any info or leads..