weird noise!

[dyne_79]

My 93 2wd with a 5 speed is making an odd noise. While moving I can hear a very rythmic sort of "wom wom wom wom" that gets faster with rpm. It's consistent in every gear. You can almost feel it resonate in the cab. Sometimes I can get the noise to stay if I depress the clutch and hold the throttle free revving. However, I can't hear the sound if the truck is stationary free revving Truck is all factory right now, other then gauges and kdp tab. I did not hear the noise when I bought the truck but it had a seized fan clutch which made a huge roar. I put a new fan clutch on when I tabbed the kdp and immediately noticed the sound on the first drive after that project. I also tightened all the bolts on the front of the engine with the timing cover off. Anyone have any ideas? This is difficult to diagnose as it only does it while moving...

[diesel freak01]

I would check the u joints. Does it get faster or louder with speed? Might be a bad spot in a tire also.

[dyne_79]

It gets faster with rpm, not so much speed. The tempo changes as I shift gears. And I just replaced the tires. The sound was just the same.

[CumminsPower59]

How's the lube in the transmission?

[dyne_79]

I've also changed the oil in the transmission. Over filled to five quarts. I do have a rattly throwout bearing idling in neutral though

[PToombs]

I'd check the pinion bearing and rear end lube too.

[dyne_79]

It seems to be engine related to me but I'll check that out anyway. Other suggestions?

[dyne_79]

Pinion bearing is tight, no wiggle

[DodgeFreak]

engine mounts and trans mount.

[dyne_79]

Not really seeing anything in the mounts...

[dyne_79]

Anyone have more suggestions? The truck still runs a drives perfectly. It just bothers me but I don't think it's terminal

[PToombs]

Does it have a carrier bearing, check that for a dry sound or looseness. I wonder if it's something dumb like the pilot bearing going bad?
Only other thing I can think of is to check the end play on the crank to see if the thrust bearing is getting bad. Play should be about .005-.007 IIRC. Anything over you'll need to think about a set of bearings in it.

[cougar]

my 91.5 did that. It was the fan clutch. Went away when I replaced it.

[dyne_79]

Mine is brand new though. Guess I wouldn't be surprised if that were it though