Truck Shake???

[coryb9985]

Hey guys im out of ideas. I got 2003 GMC 1500 Z71 extended cab. The truck shakes and or vibrates with a kind a bounce to it any where from 40-75 mph. Its not consistant. The road character seems to make a difference some times. When the brakes are applied sometimes it bounces/shakes but doesnt seem to be a rotor issue since the bounce/shake is in the whole vehicle not the steering wheel or pedal. You can even see the seats in the truck shake. I have had the tires rotated and balanced two different times by two different shops. I have had the drive shaft balanced and u joints replaced. I have visually inspected the brakes and everything looks ok. The alignment has been done as well. Any idea on what else it could be or has anyone had the same issue. Thanks Cory.

[waumo1]

Maybe your shocks are shot. My 1998 Ext Cab LB Z71 had a horrible bouncy feel brand new. I replaced the Bilstein shocks with Edelbrook IAS shocks and solved the problem. Sold the Bilsteins on ebay for a profit. My Challenger has Bilsteins and I love it - go figure.

[07sierra8.1]

This may be a far stretch, but I had my yoke nut come lose on my race car one time on the rear end, it made that car viberate like i never felt before, tried to run 3 races, did the same thing you did, changed the brakes, tires ect...no differance..pulled the drive shaft out and was able to spin the yoke nut by hand...tightened it back down...viberation gone.

 

I would be very surprised if this was the case with your truck but its just something easy to check over while your troubleshooting.

[Debo511]

Put a couple of hundred pouns in the bed of the truck behind the rear wheels. If concern is better it is what is call " Beam Shake" There are updated rear cab mounts for this concern.