Transmission Fluid Change interval

I have a 2012 EL Unlimited that I got used a few years back and is now approaching 150,000. I contacted a mechanic I trust about doing a transmission fluid change. I was under the impression that 150,000 is the first time tranny fluid change was needed, but he said if it was never done before, I might be better off not touching it as long as it is shifting fine and not giving me issues b/c he's seen several that start causing issues shortly after a fluid change if one waits this long to do it. I don't know if prior owner changed fluid. I never tow and don't think prior owner did either, but obviously can't be certain. It shifts fine now, but maybe a little heavy like vehicles do before changing tranny fluid.

Would appreciate feed back on:

1) what is the official and suggested interval to change tranny fluid.

2) if never done, is there any merit to the view of not changing the fluid now? Seems like an odd thing to suggest, but he talked himself out of work.

Thanks.

https://www.expeditionforum.com/threads/transmission-drain-fill-at-175-000-miles.50162/#post-460248

If you use the Search field in the upper right corner and limit it to this forum then you'll find posts on this topic of which the above link contains several.

Thanks. I found this last night in searching more on the topic. Missed it the first time. Thank you for the help. That forum was perfect.

I was in similar situation last month with a new to me 09 Exp with 147k miles. My personal mechanic refused so I took it to Ford where they were against a flush but I specified I wanted a pan drop, fluid drain (partial) and new filter. When I got receipt it looked like they charged me for a flush but after asking advisor he said that it was drain/fill. So I’m not clear on which they did but trucks shifts much better/fine now. Before some of the shifts seemed sloppy/delayed/slow but now they all seem crisp. I plan to tow a 8-9k boat with it so wanted it as optimal as I can get.

I had a hard time believing that it was not prudent to replace the transmission fluid in a high mileage vehicle. Never had any problems with the tranny. So I dropped the pan and replaced the filter and fluid. 6 months later the transmission failed. Unrepairable. 6 thousand for a remanufactured one, installed. Coincidence?? Who knows. Next time I just might leave well enough alone. It's an 07 Expedition XLT that had about 165k miles at the time of failure.

Kenomni: Thanks for input. I didn't see your reply until right now ... 2 hours after picking mine up from having the fluid changed! I guess we'll see what happens. It seems to shift better now (like rowekmr said), but could be in my head. Fingers crossed.

Did you get warning signs of it going or just one day crap out on you? Thanks.

Always changed mine at 100K miles... sometimes went to 120K. Never a problem.

Since this seems to be an on-going question, I thought I'd update this with time. Right now, I'm 100 miles past the fluid change the transmission is definitely shifting more smoothly, particularly downshifting. Night and day difference. Assuming this doesn't lead my transmission failing, thus far definitely glad I did the change. Should have done it sooner than 150k for sure.

My post fluid change experience similar. My transmission definitely shifts better.

I had my trans flushed at ~95k. Then I had a drain/fill done around 150k. I'm at 205k now. After losing a high-mileage trans to a flush a few years ago I won't do that again, but I may do a drain/fill again soon.