I have a 4WD 2500 that makes a grinding noise from the front left on right-hand turns. It's especially bad during medium-speed sweepers where I'm loading-up that corner. The pitch changes with vehicle speed so it's something rotational. It doesn't matter whether it's in 2WD or 4WD.

On the lift it doesn't feel like there's any play in the wheel bearing or U-Joint, but everything is huge and I can't produce anywhere near the forces that those parts see driving down the road.

Any tips on diagnosing this so I can order some parts?

 

Likely a bad wheel bearing, or hub/bearing unit, as the case may be. Symptoms point in that direction. Jack it up, give the wheel a spin, see if it feels crunchy, or, just not-quite-right.

 

It feels smooth on the lift both when pointed straight and at full lock. I can replace that stuff but I hate shotgunning these things and hoping something I changed fixes it.

 

So, go for a ride. Nice quiet, deserted road, good (decent....) surface. Play the slalom game, and bounce from side to side on the road, hard as you can manage. If it's a wheel bearing, it will be loud in one direction, but get quieter going the other. If that happens, that is definitely a wheel bearing.

 

I concur - that is exactly how I found the issues with my 300.

 

I bet its a dry axle u-joint, the one inside the hub. My 2010 did the same thing. The stockers don't have a grease nipple, my new u-joints have them now.

 

i would run it in 4x4 on the lift (so the front wheels will be driven). the axle shaft ujoint doesnt know the difference whether its on a lift or the road and should make the noise in both scenarios if its the culprit. hub unit will notice the difference as it wont have a high load on it on the lift. if it makes the noise on the road but not on the lift then likely its the hub unit. if its the hub unit i would replace both sides at same time with something like skf or possibly oe if its timken. dont bother with the cheap autoparts store junk especially if it says china