djack

I am new to this forum but an old Lexus owner. I have a 2001 LX470 that has been great for many years. This week it started shaking intermittently while driving. Its not a vibration it is more of a shake through the seats and floor, so I had the tires checked and rebalanced. That didn't help. The shaking will start at any speed and doesn't go away until you come to a complete stop. It can be violent, to the point I need to pull over and stop.

I've had the engine and transmission mounts checked by a dealer. They were OK. Anyone else have this problem? It almost seems like the all wheel drive system is not functioning properly but the transmission seems to be fine. The shaking is not coming from the engine or trans, it is at the wheels/suspension.

Thanks in advance for the help.

V8_Fan

Need more details. Does the shaking increase with rpm (ie, decrease when the transmission shifts to the next higher gear) or does it steadily increase with speed? If the latter, did you make sure you didn't lose any balancing weights on the driveshaft(s) or didn't hit the driveshaft to create any misbalance? Did anyone remove the driveshaft after any service? Do any of the wheels have mud lodged in the back side that would affect balancing? Are the wheels tight? (jack up car, pull on tire in different directions and check for play) Does the shaking come from a particular wheel or front/rear or equally at every wheel?

djack

Jim: The shaking increases with wheel speed and is independent of the transmission speed or engine rpm. It can start at any speed. I just had all the wheels balanced and double checked for balance at the dealer. The wheels are clean, no mud or dirt, I haven't had it off road for a couple months. The driveshaft has not been removed for any service, it looks OK and doesn't have any play in the U joints. The wheels are on tight, no loose lug nuts.

The shaking seems to come from all over. It is not in the steering wheel. I feel it through the seats and floor which would suggest a rear wheel problem. All the suspension parts back there seem OK; no loose bolts or anything. I have not hit anything that could bend or break anything either.

I am thinking it has something to do with the differential or maybe torque converter. The AWD may get out of sync and cause the wheels to skip or jump over the road. Could that be it? Would a computer be responsible for this. What about the TRAC system? Could it be causing this?

Thanks for the help.

V8_Fan

Are any of the driveshaft weights missing? Every driveshaft, regardless of make, needs to be balanced (this is done when new, but it is certainly possible for a weight to fall off. Don't know about the 4wd getting out of sync, never heard of that. Try posting to ih8mud.com under 100 series tech. You'll get more opinions.

djack

Thanks for the help Jim. I will check the drive shafts and try that other forum. If/when I figure it out I will post the solution.