Toyota Highlander mystery WOBBLE

My 2006 Toyota Highlander AWD developed a wobble as described by our mechanic. He attributed it to the fact that we bought two tires and the radius difference of new tires on front and older on rear caused a strain to some components. Our first course of action was replacing all four tires and replacing fluids in transfer case and trans. This immediatly improved the wobble substancially but not totally. The wobble increases in intensity the further it is driven, IE the hotter something gets. The wobble is only under load (acceleration) and seems to originate from somewhere forward of the center of the car. My mechanic has had the car for four days and cannot seem to pinpoint the problem component. Any ideas out there?

Did abs light come on? If tires were that far off it would have had abs or traction light on. If not I wouldn’t think tire height was that big a deal. Is it a wobble or a binding in transaxle? I have seen axle ratios off front to rear cause the front to lift and bind. If it is binding on one side in a jerking fashion could feel like wobble. I’m not sure what the differential is from front to rear but may have been damaged. A viscous clutch may be damaged. Not a tech just a guess. Please post if you figure it out. Lets learn together.

No warning lights came on at all. Mechanic calls it a wobble. It feels/sounds to me like what I would call a rythmic thumping. It does seem like the tire height differences was the or at least one issue due to the immediate improvement which was dramatic after the tire changes. Mechanic does suspect drive shaft damage or viscous clutch damage as possibilities but has not been able to rule on one or the other by physical inspection. My fear of course is paying for attempted repairs if we cannot be sure of the part that is damaged. In other words best guess trial and error repairs can get very expensive. Thought from history of car and question…when I first purchased the vehicle it had a leak (rain) that would cause the ABS and tractin control lights to come on until the components behind dash dryed out. The source of the leak ended up being the sunroof drains and I fixed that so no more leak. Now I am wondering if ABS/traction computer could have been effected by rain water leading to damage to parts under the car controlling traction etc. ? Could computer not telling the parts what to do correctly lead to damaged parts?? I will post what I find out as things develope. Thanks for any comments or suggestions. I have always liked Toyota vehicles and my Sequoia with 227000 miles is still a great reliable ride. This Highlander is giving me headaches galore so far.

Well I am lost. My mechanic kept car for two weeks trying to figure out the problem. He took it to a Toyota dealership and spent two hours with a Toyota mechanic with the vehicle on the rack. The end result… no answers. Between 25 and 45 miles per hour my car now shakes like mad and so far no one can tell me why so I can fix it. Frustrated wobbler. ??