OK, my long and sordid tale of transmission woes is all over these boards https://www.clublexus.com/forums/gs-...ml#post4541769
, but as a summary:
GS430 factory tranny goes out at 27K miles, replaced by dealer under warranty. Second tranny goes out at 45K, replaced by dealer under warranty. Third tranny goes out just now at 85K, no warranty
I went to the dealer, an independent Lexus mechanic, and a transmission shop, all with same answer - these trannies never go out, we don't know why yours keep failing, but yes, it needs a new one, so it'll be $3500 to replace.
Being stubborn (and not willing to spend $3500 at this point), I started obsessing and trying to understand why they keep failing so quickly, if no one else is seeing this problem.
I decided that the problem must not be the tranny, but the interface with the car - cooler, ECU, wiring, etc. So I checked the cooler (good flow) and wiggled the connectors, oh, and replaced the battery, because it was dying.
And guess what? The problem is gone!!!!!! Tranny works like a champ. At first I thought it was the connectors, but then I looked at the paperwork, and here is what I saw - when the original owner complained of tranny problems, he also complained of poor starting, so the dealer replaced both the tranny and the battery. The second time, the battery was also getting old, and needed to be replaced within three months of the tranny being replaced. And same this time around, the battery was again on its way out when the tranny started acting up. See the pattern? Old battery - tranny problems; new battery - no tranny problems.
I would have never believed this to be possible, until I did some googling of this phenomenon, and it is all over the place:
Unbelievable that none of the "experts" (Dealer, independent mechanic, tranny shop) had even considered this, but just wanted to replace the tranny...
Anyway, just want to spread the word that if you see this happen to you, check the battery before spending the $3500... I am going to throw myself a party with the money I saved!