Could it be the Air Ride Suspension?

[Naevoid]

I have a 1999 LTC and at 70 mph the rear end will give a vibration when the speed gets an increase. The vibration only last for a few seconds but makes the car shake bad enough to feel it. I also just had to replace the rear tires which you could feel the belts worn thru the tires on the inside bottom of the tires. Could this vibration be caused by the Air ride suspension? and if so what could the problem be?
I need help?

 

[abe_lincoln78]

Sometimes you can feel it when the pump comes on. If the PCM is set to check and adjust ride height at 70mph. With that you would hear the pump come on and do its thing for a second or two or three and then turn off.

One reason the pump comes on after that initial rise in suspension is because when air is compressed into the spring it heats up and expands. When it cools back down to ambient it contracts, which allows your car's rear end to drop a little. The air ride will at some point come back on to make up for that sag.

It could also be your torque converter coming out of lockup when you push on the accelerator. If thats whats happening you have a date with the dealership or transmission shop in your very near future.

*looks away from crystal ball*

 

[Naevoid]

thanks

Thanks for that info. I don't think it is the pump because the rear end vibrates when you give gas or let off the gas. It's kind of like draging a heavy table across a tile floor and the table kinda hops when you are draging it. Someone told me it could be the trans. but it feels like the rear end.

 

[dRock95MarkVIII]

How many miles?


May be axle bearings.


Can also be bad u-joints, causing driveline vibration at high speeds.

 

[no0c]

How many miles?


May be axle bearings.


Can also be bad u-joints, causing driveline vibration at high speeds.

I vote for u-joints !