Shaffer

I have recently noticed that when I am steadily going about 35-45 and I rapidly accelerate out of overdrive to pass someone or whatever- my car will initially make this odd sound until it shifts down into 3rd. It almost sounds like you are running over one of those white "wake-up - rumble" strips on the pavement that you see at intersections. It sounds like it is making the noise when it comes out of "lock-up" mode. I cannot feel anything when it does it- only the sound. Also- it does not always do it even at these speeds. At 55-up, it does not do it. I never noticed before, as I lightly drive my Lexus and never accelerated like that before. I was suprised when it did that. I have been occasionally doing it on purpose to try to see exactly what it sounds like and where it is coming from.
Someone said it could be a bad u-joint, or differential, as my car also has a vibration at speeds between 40-58 mph- that does not seem like it is tire related. In addition- the transmission shifts fine. I am thinking/hoping that it is not the transmission doing this.

BTW- my car has 226,800 miles.

Any advice appreciated.

usermel

Hi bro i know you dont know me from a can of paint and i dont know how your cashflow is but if you can afford to take your car to an OFFICIAL LEXUS DEALERSHIP SERVICE DEPARTMENT DO IT.There is no way to figure out that problem without proper analysis.Cars are like humans are when it comes to disease they give of signs to warn us like our body.If you dnt have extra cash then fine a certified luxury car mechanic who should be alittle cheaper.You need someone who has prior experiece working on an LS and other Lexus models he or she should be able to identify or find the problem.Also you didnt say your miles on this car.Its a 1990 LS 400 so i figure that it is at least 13 years old depending on original purchase date if you have VIN# most dealers can give you history of car if you purchased it used.GOOD BLESSINGS on nothing being wrong with car.Oh just re-read you thread and saw miles 220,000 miles is up there so sound could be normal for an aging LS 400 but check with certified professional so if problem is minor it doesnt become major.