2001 QX4 automatic transmission shift flare

[attofarad]

My GF's 2001 QX4 (142k miles) has had the slipping-when-cold characteristic described in service bulletin ITB01-051a for quite a while (forever?), but I had personally experienced it only recently -- not often cold here, and she used to park in her garage until a year ago, and I don't drive it much. It seems to be getting worse lately.

I tried changing the TCM from the 31036-4W001 version it came with to the -4W002 version, but behavior seems exactly the same.

Before replacing the solenoid assembly with the updated part 31940-41X15, I'm trying to find out whether people have found that it actually fixes the problem.

Also, when removing the control valve assembly to replace the solenoids, are springs or seals or whatever likely to drop down and fall out? It looks straight forward and relatively simple in the FSM, but comments on any problems I'm not anticipating would be appreciated!

Also, any recommendation regarding whether a different fluid would have any effect on this problem?

[Q45tech]

9 year old automatics [with 142k] are usually done depending on frequency of ATF mainteances.

All the seals and passages wear and fluid leaks around things lowering shift pressure.

The usual solution is to replace with oem or high quality rebuild AT if you desire to return to near new feel.

Over 20 years of Q45 ownership I am on transmission #3 now and fully expect to replace it one more time.

The TCU software is preprogrammed for new conditions and varies with ATF temperature per FSM.................measure the various port pressures per FSM.