JustSomeRandomGuy

I had the same problem on my 2001 ls430, but mine was caused by a cracked lens and moisture accumulation behind it. Dealer wanted $1200 just for the part. I bought a used one from yahoo.jp for about $90 shipped to the states and it works fine. I had to take off the front bumper cover and the impact bar because the radar is mounted behind it, but it is definitely do-able yourself.

The only issue i have is it is calibrated for a right- hand drive car so sometimes it detects a car on my right during a curve and disengages, or downshifts to slow down, but if I shorten the radar distance it doesn't happen as much. I like to hang back from other cars to avoid rock chips.

I replaced my lower pan gasket in an afternoon in my garage but my upper one was leaking a bit. I've used AT-205 oil seal reviver in my engine for two oil changes and it stopped leaking. I recommend trying it before spending that kind of money.

https://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM/ref=mp_s_a_1_3?crid=O5E3NYLWQXW3&keywords=at+oil+seal+reviver&qid=1667159380&qu=eyJxc2MiOiIxLjQ0IiwicXNhIjoiMC4wMCIsInFzcCI6IjAuMDAifQ%3D%3D&sprefix=at+oil+seal+reviver%2Caps%2C791&sr=8-3

I've had good luck buying a replacement Amp for my Mark Levinson on yahoo.jp and it was only about $180 shipped to the states. Might try there for a good factory replacement if all else fails..

I have a similar issue where i feel a clunk downshifting on a slow,  uphill turn. I took my 2001 ls430 to a transmission shop and they determined it is the bearings in the tail shaft, but that i didn't need to have it repaired for another 50,000 miles or so unless it really bothered me.