I have a 2013 F150 with a eco boost and a trailer tow package . I mostly pull a trailer with a large John Deere Gator a lot . I bought it with 150 k on it . Last week I found a small transmission leak and had it fixed . I noticed the fluid was real dark . I have always heard never change the fluid in a automatic after it has 100 k on it . Does this still hold true on newer models ? Or should I just leave it a lone . I have only had it for 2 months now and also do not know if the previous owner did or not .

I would change the filter and what fluid is in the pan. But I would not flush the torque converter. Fluid may be dark, but what does it smell like? Does it smell burned? If it smells burned, all bets are off on that transmission.

it's possible that your tranny is sealed. my 15 is.

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Click & Clack always said to change it because if changing the fluid screws up the transmission, it was already screwed up.

This

I would not change it. Having worked in auto parts for a few years and managed a ford parts department also for a year I would absolutely not change it.

What does your owners manual say?

Any advise here is worth about as much as it cost you!

Dealer fixed the leak and it is fine . Thanks for the advise , I did not know it was sealed and how to check the fluid level . As always a lot of great people here !