Vibration only in 4wd
 

2001 Ram 2500 360. I have a vibration that starts only in 4wd and noticeable at about 30mph and gets worse as you go faster. When you take your foot of the gas it slightly gets better. I checked everything and don't see anything wrong. I did have the front driveshaft off to replace a universal a while ago. I did flip the slip part of it (part that bolts to the diff pinion) 180° and didn't notice a difference. I didn't mark them, I was in a hurry. I'm in Michigan at the moment so have a limited amount of tools. Thanks for your help!

Might be ujoints at the axle. I once had a rusted ujoint but it was silent until in 4wd. Scared the crap outta me! Sounded like a Velociraptor scraping on a chalk board. Point is, they can run smooth until loaded in 4wd.

They were replaced to(right before winter), but the one I rigged so I'm wondering if that could be the vibration.

I would have a look at the CV joint at the t-case. I can dry out, and bind up, and its REALLY hard to tell without taking it apart. (which is a whole 'nother pain in the rear.)

I checked them when I had the driveshaft out as I replaced one earlier in the year. I wonder if it's a wheel balance issue. As they used them balancing beads for my 37s. Because I also have a vibration starting at 55-65 in 2wd from what seems like the rear.

Your front driveshaft spins all the time?

Mine will after this week I'm eliminating the whole cad with a delete plate

I was talking about axles, but yes, the front driveshaft spins from the pumpkin freely as the tire moves. But the t-case is in neutral, so there's no power from the trans. The passenger stub shaft also spins but not the intermediate shaft. Two things happen when in 4wd: the CAD couples the stub shaft to the intermediate shaft, and the t-case engages 4H or 4L forward power from trans. Otherwise everything is still connected and thus spinning. What eliminating the CAD (Central Axle Disconnect) does is re-connects the passenger axle to the pumpkin with a one-piece axle like the driver side solving potential vacuum issues but allowing more drag. Dodge did the CAD to help with MPG.

When I cleaned and painted the front driveshaft on the 00, I went with semi-gloss black and put a gray box where the numbers were stamped. I never see that shaft turning, unless its engaged by the transfer case. I had a crazy thought about candycaning that shaft, but then I came to my senses.

Maybe the D60s are different. I even removed mine once checking for a vibe I had and watched the flange on the diff turn. That means the shaft turns when bolted to it. It's just free spinning, no power is applied since it's disconnected at the transfer case.