ATF change and Seafoam: 7,000 mile update

[John Galt]

Back in Feburary 2009, I changed my ATF and a did a seafoam treatment. Its been 7,000 miles now, and the truck is running perfectly. The transmission shifts smooth and crisp, and throttle response is great.

Based on some research I did subsequent to my ATF change, I learned that most ATFs have a starting TAN under 1.0, and the ATF spec calls for an increase of no more than 3.0 for ATF in use. The TAN from my ATF was 3.6, so it is very clear that, at 83k miles, my ATF had reached the end of its life and needed to be changed. So much for "lifetime" fluid.

[ncsucarjock]

My owners manual for my '04 4.4i states a change is due at 100k for ATF. I did it at 49,500. Currently at 59,100 (gosh, that change was in august...), No problems no issues. I didn't get it analyzed, so no hard data. Shifting has not changed before or since.

[John Galt]

Originally Posted by ncsucarjock

Shifting has not changed before or since.

Same here. What fluid did you use?