Does anyone know if the forum collectively determined a surefire way to get the very often complained about 2-3 cold shift "bump" to go away?

I just did my 4th drain and fill two days ago along with a brake fluid full flush and it still is doing the bump if I'm not in PWR mode and being more aggressive than I would like with the throttle. It's difficult to drive the car in a relaxed fashion with this issue and while I'm not concerned about durability/having an actual problem it's annoying to live with.

I know it's not ever going to be as smooth as my 430 but I at least want it to be smoother than non-Lexus cars.

Some threads seemed to suggest I throw a battery at it? I don't think this would work since I already tried putting it on a tender at night to make sure state of charge is at max and it makes no difference.

I don't have time to really look at it right now and am hoping you guys have a idea or known fix I couldn't find. Thanks all!

 

In my case, a full transmission flush with transmission ECU reset solved the issue.

 

I guess I'll tell it to do a valve body relearn and do one more flush, the fact it worked for you is encouraging but if I remember you have an AWD?

When you say trans ECU reset do you mean VB relearn or something else?

 

Yes, I got AWD. I am not sure (do not remember) what is called in Techstream, but I used one of transmission utilities to trigger transmission re-learn. You will need an OBD adapter that supports such functionality. My $20 adapter did not work but a DrewTech one did.

 

I have Autels top tool lol! Was just curious if it's not called the same thing in mine vs techstream since I know you use TS. Mine calls it a valve body replacement relearn.....

I need to order a cable for my laptop already since I have VCDS, VAGCOM, Hondata on it but have been dragging my feet on techstream since my main tool seems to be able to do everything I've sent it's way outside of VW group.

Thanks man

 

I had a chance to play with my car today after I finished the other 460s brake actuator removal....I think I solved it.

I did another flush and relearn and this time I intentionally closed the overflow the second the stream of fluid changed from solid. This seems to have fixed it, I guess it was just slightly under filled by allowing the stream to stabilize into a thin one.

I also confirmed this by doing it "correctly" and letting it sit while a attended to my friends ES to cool off and the bump came back. I ended the day with him helping me do a really full flush with 3 drains back to back and him setting it in R/N/D on the lift to make sure all the old fluid was gone. The last fill was done putting the plug back once the stream changed....

I was at the shop far too long today. Oh and an item of advice/something I have found, it's far easier to add fluid from the rear service port. Much much much easier to open and get to, 17mm Allen bit is required. A long type (4-5 inch) is needed and you have the perfect angle around the exhaust to get to it. It uses an O-ring and is very nice vs using the 24mm side fill. Just so everyone knows.....I'm having a fun time with learning this new car!


Bottom view of the rear port

Inward/toward view of the plug from the rear of the car, very easy to access even if you don't have a lift IMO. I may be completely wrong though since I have only done this on my lift