This is driving me crazy!!!

[noelb]

Ussually when you go over a bump you just feel the bump of the suspension handles most of it. I have an issued with my k2500 Suburban in that when I drive over a man hole cover or small bump that the cabin seems to vibrate for about a second or two after.

I replaced the Adjustable Koni's with Brand New OEM Bilstien and this made it worse. The Konis' were old and only adjusted 3 half turns. I adjusted them to nearly maximum at 5 half turns and this has made some improvement but not enough.

The lower ball joint have only about 2-3 thou movement.

Anyone have any ideas? :confused: I gave up initially thinking it was normal but I am sure it is not. This has been bugging me since I bought the car about 25k miles ago.:(

Could it be Bushes. The toyota I have has 195k miles and is four years older and is as good as new.

I suppose I could just lower tyre pressure to say 30lbs. :D

[wade-ve7trw]

what type of vibration. is it up/down or left/right. is it more of a steering wheel shimmy, Need a little more information on the vibration you are experiencing when going over a bump and at what speeds

[noelb]

It is like a shudder through the dashbaord and cabin... perhaps an up and down vibration, definately not side to side. (body mounts???)

Smooth through the steering wheel. (no vibration or or anything through the steering column or steering wheel.)

It's just like going over a bump except that it feels like the car is going over several of them.

Not really sure if that helps.....

I am generally not at a loss as to cause of symptoms, but I just cannot pin this one down. I have thought about replacing Bushes front and rear, Balljoints and body mounts etc. but this is probably a lot of unneccesary work. Could it be one of these??? if I knew for sure I would have ordered the parts.

Thanks

[wade-ve7trw]

independent front suspension--check torsion bar bushings--steering damper?
solid front axle-- spring bushings
motor mounts and transmission/transfer case mounts
weak springs on front end
last resort cabin mounts--usually has a lots of squeaks and other problems at same time

[noelb]

Thanks. New steering damper so I suspect I can rule that out. It is IFS so I will check torsion bar bushings.(I wasn't aware that there were any...) I hadn't thought of the Engine or Trans mounts so will check those also.

Thanks again,

[DA BIG ONE]

I have a 1999 and get the same shudder, vibration and have concluded that the heavy K2500 series w/65td suspension has an even heavier rating than a regular gas powered K2500 and at certain speeds this gremlin appears especially on washboard back roads.

Tire pressure, speed, vehicle load all play a big role in this so driver adjustments to speed, air pressure are critical in the reduction or elimination of vibes/shudder.

No bushings on your torsion bars, however if they have been cranked to help larger dia tires to clear this can be an issue.

Get under burb and check drive train closely. If you have an NP246 autotrac this can contribute to what sometimes feels like vibes/shudder when in auto mode because of clutch engage and dis-engage on certain surfaces but is usually short lived.

[Robyn]

With time and miles the torsion bars will sag off and the front suspension then sits pretty much on the rubber stops and does little to soak up the bumps.
Check the ride height and be sure the A arm is not sitting hard on the rubber stop. If it is adjust the torsion bars to raise the front end a little.
Be sure your ride height is equal on both sides.

Had a 95 that we bought new and after about 60K and running up and down the rough roads getting home I noticed some changes to the ride.
Adjusted the bars and it took care of it.

Good luck

Robyn

[allformike]

does the weight need to be off the front end to adjust the torsion bars. mine isn't sagging, i am going to get bigger tires this weekend and i think they might rub a little, so this would be a good way of getting out of buying a lift kit. but doesn't cranking them stiffen the ride?

[6.5 Detroit Diesel]

Cranking up the torsion bars will lift your ride. I lifted the front end over an inch. But don't be trying to make it work instead of a lift kit. The higher you go, the stiffer it will get. I went as far as they could go and it felt like there was no suspension up front at all. Actually thought something was going to break every time I went over a bump.:eek: