Big Bang

[Hobowon]

When I come to a rolling stop, just a few feet from the full stop and what appears to be when the RPMs drop to idle, I get a big slam in the differential. Won't occur if I do a more aggressive stop which is not my driving style; I typically come to a smooth rolling stop. Sometimes incident won't occur with the air on and overdrive off. Never does it if I come to a hard stop, not slamming on the brakes, but harder than a smooth stop. Now for the "rule outs: Lexus did a top end carbon blast and also cleaned the throttle body and air conditioning switch; idle speed verified to be at factory specs; got a new drive shaft whth front and rear couplers; Lexus removed the third member and sent it to LA for mic, came back within parameters; had tranny flushed, one mechanic questioned the rear stabilizers and (sort of) worn rubber bushings; strange as it may seem, when I have a tech do a ride with me, I can't duplicate the problem - one guy thought it might be the extra weight; maybe I should go to Home Depot and buy a couple of 100lb sacks of concrete an put it in the trunk. Everyone says the tranny is healthy. I have taken the car to two Lexus dealers, one automatic tranny shop and one Foreign car shop and no one can diagnose it. Recently, I came to a stop and I swear I thought it was going to blow the rear end out. Here is a "sorta like": come to a slow stop, the tranny gears down to idle speed, just before the full stop, look out!!! Gives me the notion the tranny "goes to sleep", then suddenly "wakes up" and says "gotta take up the slack." The way I try to describe to the techs is: short of stopping, slack is taken off the drive line, then gets taken up forcefully. Won't do it any speed but as described. BTW, the car has been well maintained, has 142k.

Just a quickie: I recentlly discovered that if I disengage the overdrive (overdrive off), the sucker doesn't go "bang". I spoke to a guy at one of the repair shops that suggested it might be a defective overdrive unit. And woould you believe, Lexus does not sell only the unit - you have to buy the whole tranny. I will resolve this problem if it takes the rest of my life. Maybe I should consider just buying a tranny and get on with life. Anyway, I'm still open to suggestions, so bring 'em on down. Thanks.

[LexSC400328]

this is merely a suggestion because my car does this too when its cold out and the first few stops...it feels like a sudden thumpppppp. possibly tranny mounts? maybe unless your positive its the transmission that would be a good place to start before replacing the entire transmission...once again just a thought.

[Cynical]

It very well could be your end links, when mine were bad I would get a thump only when going in reverse at slow speeds and the links looked fine but when I changed them the thumping stopped.

[UCF3]

It very well could be your end links, when mine were bad I would get a thump only when going in reverse at slow speeds and the links looked fine but when I changed them the thumping stopped.

Are you sure it wasn't a "click" instead of the thump? When I had that problem on my old LS4 it used to click.

[Cynical]

It very well could be your end links, when mine were bad I would get a thump only when going in reverse at slow speeds and the links looked fine but when I changed them the thumping stopped.

Are you sure it wasn't a "click" instead of the thump? When I had that problem on my old LS4 it used to click.

Nah it was a thud it almost sounded like I was hitting a deep hole