Vibration at 35 to 45

[Bradley George]

I have a slight vibration/rumble in the steering wheel between 35 and 45, at 55 and faster it drives very smoothly. Took it to the RAM dealership, balance the tires, no improvement. I got underneath and found a little play in the front output shaft of the transfer case. Does the front driveshaft rotate while in 2WD? Is this something I should worry about? 2021 5500 6.7 4x4 Dynamax motor home.

 

[jsalbre]

Some rotational play isn't unusual. There's always some slack in the driveline. The front driveshaft shouldn't rotate when driving in 2wd as the front axle disconnect is disengaged and the diff internals should be spinning with the ring gear (and driveshaft) staying stationary.

I'd have your alignment checked by someone other than a RAM dealership. RAM's factory specs are wrong and leave too much toe-in. I'm not sure you'd get vibration from that, but it's possible depending on the road surface you're driving on.

 

[Rockcrawlindude]

As @jsalbre said, you can turn the driveshaft a tiny bit that’s normal. Does the 5500 have the axle disconnect? I imagine it does and the other reply is correct about how the front axle and driveshaft behave normally with CAD

if you grab the driveshaft and you have play in other directions (up/down, in/out) from the front output of the tcase that’s not good. I would imagine any play at the output shaft would be accompanied by a leak there.

Do you feel the vibration in the steering wheel or in the seat?

 

[Bradley George]

As @jsalbre said, you can turn the driveshaft a tiny bit that’s normal. Does the 5500 have the axle disconnect? I imagine it does and the other reply is correct about how the front axle and driveshaft behave normally with CAD

if you grab the driveshaft and you have play in other directions (up/down, in/out) from the front output of the tcase that’s not good. I would imagine any play at the output shaft would be accompanied by a leak there.

Do you feel the vibration in the steering wheel or in the seat?

Steering wheel

 

[44Dan44]

Welcome to the forum @Bradley George

 

[joshuaeb09]

Assuming the alignment is indeed good and you don't have any issues with ball joints, the tie rod joints, or the draglink, then it sounds like tire balance to me. Did they check the wheels and tires for runout when they rebalanced them ?

I've never had good luck getting tires on HD trucks "perfectly" balanced so I run centramatics for dynamic balancing. Assuming all the other things check out I would look into centramatics or balance masters as they can work wonders. I still get mine spin balanced every once in a while, but the centramatics are doing most of the work.

 

[Poolmonkey]

Centramatics, two sets of tires…couldn’t get mine just right until putting on new wheels.