Vibrations when coasting

[Yeret]

Welp, got another thing popping up that I just noticed. When I'm coasting from highway speeds (70 MPH) my truck is fine until right about 40 MPH. From there all the way until I stop, I can feel slight, continuous vibrations in the steering wheel. What seems the best place to start?

Since we're talking about vibrations, while driving highway speeds, I can feel heavy vibrations through the transfer case shifter. Hell, you can even see the stick shaking! Is this normal?

Also, a bit off topic, but I'll ask since I'm posting a topic. When the weather is cold, when I shift out of 4-wheel drive, it doesn't seem to disengage right away. I roll forward several feet, then I can feel (and hear) the front axle disengaging, almost kinda forcefully. This does not happen in warm weather. What could be causing this?

 

[rowdyram]

Minor Shaking t case seems to be normal for a lot of floor shift 4x4s, worse with more aggressive tires.
It is also normal for the 4x4 to not disengage right away. Its good practice to reverse a few feet after shifting to 2wd to release the load on the gears so they can move.
As for the shake when coasting start with tire balance and checking for broken belts or separating tread.

 

[Yeret]

Well, I bought 4 brand new Cooper tires from the local Theisens a few months ago, so I certainly hope I don't have tire issues, LOL.

I suppose trusting $8/hr dudes to properly balance your tires can be a shaky proposition. Honestly, the only reason I had them do it was because i had to let them do it to honor their "buy 3 get 1 free" deal. Otherwise I would have had the tires mounted by the local dedicated (and reputable) tire shop.

 

[rowdyram]

Ya you can probably rule out a tire problem but I've seen quite a few new tires come apart.
And you would not believe some of the stuff I've seen come out of big tire chain stores, loose lug nuts, incorrect balance, way out of alignment after they "set" it.
Also look for evidence of a missing wheel weight it possible one didn't seat right and came off.
Did you get an alignment with your tires?

 

[Merc225hp]

Rear ds u-joints, tranny mount, things to check as well. Motor mounts are also a weak design.

 

[headhunter123]

Welp, got another thing popping up that I just noticed. When I'm coasting from highway speeds (70 MPH) my truck is fine until right about 40 MPH. From there all the way until I stop, I can feel slight, continuous vibrations in the steering wheel. What seems the best place to start?

Since we're talking about vibrations, while driving highway speeds, I can feel heavy vibrations through the transfer case shifter. Hell, you can even see the stick shaking! Is this normal?

Also, a bit off topic, but I'll ask since I'm posting a topic. When the weather is cold, when I shift out of 4-wheel drive, it doesn't seem to disengage right away. I roll forward several feet, then I can feel (and hear) the front axle disengaging, almost kinda forcefully. This does not happen in warm weather. What could be causing this?

Mine does the exact same thing! I hope it's only a balancing issue but either way, I'm still looking for all new tires.

 

[MoparMagic'00]

Id lead to think its u joints.. With speeding up they have pressure on them and when coasting pressure is released and you are feeling the slack in the joints.. One must not forget the axle joints can come into play as well as they are spinning too.