I have a bone-stock '88 standard cab that has a tremendous amount of cab shake/vibration when I hit minor bumps in the road. The front suspension (tie rods, ball joints, etc.) is all fine. No visible frame cracks. Shocks are good all around. I've replaced all the body isolation and torsion bar bushings, but this didn't help much. Is this natural (after 285k miles) or do you have any ideas of other things I should look at? Thanks.

 

Try shaking your cab side to side while you're parked it could be the bushings on the bolts that mount the cab to the chassis. Other then that I dont know but that is not normal.

 

Have u replaced the trailing arm or lower control arm braces that mount to the frame and lower control arms sounds kinda weird at my old job bodyshop we would put a floor Jack on the pinch mold and apply a light lift to see if the cab lifts doing this to each corner of the cab it shouldn't move. Normally we only did this to vehicles that have had frame damage or have been jumped indicating bent floor panes or crooked passenger compartments

 

Thanks for your suggestions. I have replaced all the rubber bushings for the cab, and bed. I just replaced the steering damper. Still the same shake. Wierd.

I will check the control arms, though I and a mechanic didn't find anything obvious when we had the thing up on on a garage lift.

 

Have the wheel bearings been checked normally if there worn they get a little play in them but usually start to audibly tell you that there getting dry and hot also can eat the spindle up as well

 

Follow-up: the violent shaking over bumps was 75% cured by replacing all the bushings at the leaf spring mounts. I had only replaced the bushings under the cab previously. It's amazing how much vibration was transmitted from the bed to the cab!

Thanks to those of you who offered suggestions.