Thanks to Richard Moore
My 99 was in the dealer a total of 6 times for this problem, and the final fix was lubricating the front sway bar bushings where the sway bar is actually mounted to the frame of the car. The problem is the friction between the sway bar and the bushings that hold it to the frame of the car. The bushings are a hard rubber and over time dry out causing them to stick to the steel bar. Then, when you push through a turn or go over a bump, the bar slips about 1/8" and sounds like a knock inside the car due to the fact that the bushings are right under the floor pan by your feet. The slipping of the steel bar on the sticky rubber bushing is the thump you hear. It appears to the driver that the sound is coming from the floor pan or the strut which is what confuses most dealers when the try to isolate it.
Take it to the dealer and have the bushings lubricated with a special rubber grease that they have for this problem. It WILL solve it! They may have to remove the sub-frame to get the bushing off. They did for mine.
So far in 5000 miles the problem has yet to return and I don't think it ever will. The grease does not wash off so it will last forever........
99 SHO Black
It seems to me that the most common sources of this annoying problem are:
1) bad/defective strut
2) bad/defective strut tower bushing
3) bad subframe bushings (although this is really a different noise.... more of a "pop" than a "rumble"
3) worn stabilizer links
4) worn (or poorly lubricated) stabilizer bushings
I plan on temporarily disconnecting my front stabilizer links. If the problem goes away, then I've isolated it to #3 and #4. If it doesn't go away, then it's probably #1 or #2.
Anyone see anything wrong with my logic on this?
'97 TR, 53K