Transmission question on an 06 w. 106k that I just purchased.

Driving it home from FL pretty much all HWY it was super smooth.

However I noticed after a semi hard acceleration up to about 3rd or 4th gear (~60% throttle) and letting off the throttle a bit abruptly for a car that pulled out in front of me, the RPM hangs for a second which is normal, but then I noticed a very slight "thump" in the drivetrain when it upshifts to the higher gear when the RPMs drop. This was repeatable when I tried it again. It's minor, but noticeable.

Is this normal drivetrain slack on a 15 yr 100k mi car with the torque converter unlocking, or a sign I should do a transmission drain and fill with filter?

Upshifts at steady throttle and downshifts coming to a stop or slowdown are butter smooth otherwise, its just this very specific condition that I noticed.

 

Your transmission fluid is 14 years old and 100,00+ miles.

Old transmissions fluid causes shift issues.

(It ain't lifetime fluid-nothing lasts forever)

Replace several quarts at a time.

Would make sense to do a drain and fill....although your transmission does not have a traditional transmission dip stick and requires special tools to refill and check fluid level.

Whatever you decide to do, DO NOT "flush" the system.

Report your findings.

 

Change the fluid, it all depends on how bad it is but I have noticed it's kinda unavoidable to an extent on the 6 speeds when you do basically as you say with not WOT but more than half and snap off during shifting. The 5 speeds are not as bad about it but have a similar occurrence, irony is I have felt new cars shift worse for normal shifts......

 

It's mild, definitely not a cringe moment like OMG get this thing to a shop, but somewhat noticeable. Was just surprised that I could feel that as everything else is butter smooth.

And to your point, my 2019 VW Atlas with 500 miles and 2019 Jetta GLI w/ DSG shift much worse than this 100k mile 15 yr old Lexus.

 

Check your transmission mount for cracks or tears. They are a common wear item that can cause rough feeling shifts if they have failed.

 

good point! will check it out at next OCI