Automatic Tranny-Service Life wit/without ATFchang

[Jimbo]

The A750 in the 67,000 mile Tundra is starting to feel just slightly sluggish on upshift, but not really slipping, maybe my imagination. Dealer told me unnecessary to change fluid before 100,000 miles. Going to send a fluid sample for analysis and see what is up. There is no dipstick. What I thought was a drain plug is actually the overflow tube for level checking. So, I'll withdraw a sample via the fill plug.

Results will be posted here and a separate UOA post.

 

[Greasymechtech]

Jimbo, if trans feels different, time for a full fluid exchange.

Stewie, don't start internet rumors and spread fear. Sealed transmissions can be serviced. You don't drop a pan to check the level.

Driving style and engineering defects probably have much to do with AT life. ATF changes is all we have if we have an inferior product or aggressive driving style.

 

[CBR.worm]

You can read the adaptation values either in INPA or Ediabas (I don't remember which one). One of the debates is whether to reset the adaptations after a fluid change, since the fluid properties have changed. I do reset the adaptations with a little bit of trepidation. I don't remember how many miles you said the car had, but if it is low miles (50K?) the new fluid properties will probably be within range of the new stuff. If you had 150K, the fluid properties may be different. after resetting the adaptations it will shift strangely for about 100 miles and will continue to quickly learn for about 1,000 after which the learning process levels out. Kind of like long and short term fuel trim.

Some adaptations are compensating for wear, others are for shift characteristics and driving style.