Vibration When Switched Into 4 Wheel Drive

Fellas,

Experiencing a bad vibration around 40mph when switched into 4 wheel drive and was wondering if anyone has some insight to fix the problem? I replaced the wheel bearing about a year ago and does not happen when in 2 wheel drive. Wondering if it's a differential or drive shaft issue?

 

I think the only difference would be the drive shaft spinning. Any mud or crap stuck to it making it off balance? Any noise when in 4WD like when starting and stopping? Have you lubed the zerks in a while?

 

Thanks Adam, I will check it out when I get home today and have my mechanic lube the zerks the next time I have it over for a oil change. Hopefully that resolves it.

 

They should be able to check the joints when they are down there. Those would definitely cause a vibration, but I figure if they were on their way you might get some noises under load. Not always the case, but its hard to say.

 

Might not actually be a mechanical problem at all.
First off, 4wd does naturally vibrate a little bit compared to 2wd. Totally normal and expected, since there is no "give" between the two axles.

Let me ask you this; how is the relative tire wear? If the tires on one of your axles are worn measurably more than the tires on the other axle, this WILL cause a significant vibration.

Second question; have you tried driving on a road that has more give? Like snowy? If the vibration goes away on a slippery road, this suggests that it is a tire difference issue.

 

Appreciate the insight and my tires are brand new with no wear. As far as slippery roads, have only driven in heavy rain scenarios and noticed the vibration start around 40mph. Never noticed it before when in 4 wheel drive and believe some components are starting to wear considering she has about 110k on her.
I will have my mechanic look her over and report back.