Vibration at 35mph

[cantvalve16]

Workin on my buddies '91 Suburban that has a vibration at 35 mph. Does it in neutral and in 2nd, 3rd, and 4th gear. Doesn't matter what you do, but at 35 it tries to rattle your teeth out. The tires have been balanced on numerous occasions and seem to come out perfect.
I am thinking it is the center support bearing, but is there any way to test one of those? I grabbed the driveshaft and it moves around a bit. How much play should one of these have?

[TC]

Re: Vibration at 35mph

I grabbed the driveshaft and it moves around a bit. How much play should one of these have?

None.

[HoosierGTA]

Re: Vibration at 35mph

Agree with TC also if you have a simular truck or b-body wagon around switch the wheels one at a time and see if thats it. Could be any thing. I've even found rotors to be the culprit some times!

[70.5CAMARO]

Re: Vibration at 35mph

that completely depends on if you are moving the bushing or if youare moving the rubber around the bushing, I just not more that 4 months ago thoguht that my wrecker ( 97 chevy 1 ton dually) needed a carrier bearing cause i could move it around, got a decent brand new one did the exact same thing. Is it 4wd? if so take out the front d/s and see if it still does it if so i would check the loosness of the pinion bearing, that is if all the ujoints are good, then again that may just have a bad wheel bearing too, hard to tell, i would put it on 4 jack stands and run it up see what happens, maybe do that with the tires off ( put the lugs back on so you dont loose a drum ) just to see what a differance it makes.

[HoosierGTA]

Re: Vibration at 35mph

Quote / : (put the lugs back on)

LOL yeah that could ruin your day!

[Loren]

Re: Vibration at 35mph

Workin on my buddies '91 Suburban that has a vibration at 35 mph. Does it in neutral and in 2nd, 3rd, and 4th gear.

Doesn't do it in first or reverse at 35?

(just kidding)

[cantvalve16]

Re: Vibration at 35mph

It is a 2wd. Haven't tried it in 1st gear yet. So the center support mount shouldn't let any wiggle be happening at all? Never dealt with a center support myself. So if I grab the driveshaft on either side of the center support and it moves around at all it is toast?

[min301]

Re: Vibration at 35mph

It's a rubber bushing, with a steel sleeve inside.
There should be slight give, but nothing like you are describing.
Ditto on the ujoints, check em.

[Loren]

Re: Vibration at 35mph

Or a slightly bent shaft...

[min301]

Re: Vibration at 35mph

Or a slightly bent shaft...

Yup, good catch.

[SpiderGearsMan]

Re: Vibration at 35mph

I don't recall suburbans having a center support bearing

[ss427]

Re: Vibration at 35mph

My '86 3/4 does...

[SpiderGearsMan]

Re: Vibration at 35mph

3/4 ... yeah , that would make sense
at chrysler my memory is getting fuzzy

[JOES66FURY]

Re: Vibration at 35mph

Check the U joint without any load on it, There should be no play at all...a slight ammount, especialy in a truck with big tires will be multiplied.....