Transmission fluid lifetime

[Kestas]

I have friends who don't bother changing fluid because the manufacturer states it is "lifetime." Of those who keep the vehicle a long time, most report their transmission starts hiccuping or getting clunky around the 100K to 150K mark. That is also the point they sell their vehicle. The manufacturer's marketing department knows exactly what they are doing.

 

[DBMaster]

I don't think drain and fills hurt at all, but with synthetic fluids, new transmission designs, and integral (better) ATF coolers, how often? I have seen some posters on BITOG posit the idea of doing a D&F ONCE during the first 100,000 miles and then leaving it alone. My plan, if I keep the car more than 150,000 miles, is to do a D&F again at that point. I did one on my Skyactiv Drive at 60,000 miles. I doubt anyone on here has anything beyond "feel good" opinions or distrust of transmission and ATF manufacturers that say the fluid is lifetime. Without statistically significant evidence (AKA, NOT ANECDOTAL) all we have is a bunch of people who are living 30+ years in the past.

 

[Kestas]

Mercedes used to tout fill-for-life. The problem was a lot of their transmissions would need to be replaced at the 120K to 150K mark. After all, their vehicles are known to last many miles. The scrapped that idea and went to service at 40K, then fill-for-life, which really means every 100K thereafter.

It is important to get the break-in debris out.

 

[Hall]

Originally Posted by Kestas
Mercedes used to tout fill-for-life. The problem was a lot of their transmissions would need to be replaced at the 120K to 150K mark. After all, their vehicles are known to last many miles. The scrapped that idea and went to service at 40K, then fill-for-life, which really means every 100K thereafter.

Haha ! You can bet that M-B has data that shows their new car buyers typically sell them before they reach 140k miles !

 

[DBMaster]

Based upon these last two posts and a few I've seen in older threads I think my strategy is sound. I kept my last car (1989 Accord) 23 years and 353,000 miles before having an accident. I used to do D&F's every 30,000 miles. The transmission wore out at 300,000 miles. I was using Mobil 1 synthetic ATF. I've often wondered if it would have gone even longer if I had used Honda DW-1. 1989 is a world apart from a 2012 Skytactiv, though. I pledged that I wouldn't keep my next vehicle more than ten years or 150,000 miles because that's when it seems like the larger expenses start to occur. I am tentatively planning to keep my 2012 Mazda3 for a bit longer than that due to just how trouble free it has been. That might make a few larger expenses more palatable. But, I do plan to replace the struts and shocks at 150,000 miles. That's not a huge expense and I can do the work myself (no quick struts for me!).

 

[DGXR]

I have always (and still do) thought that "lifetime" means "until the manufacturer's warranty expires." The car will not immediately fail at that point but there's no backup if it does. So, anyone wanting the vehicle to go significantly farther, reliably, will have to take action -- this means changing ALL the fluids at appropriate intervals, including power steering.