Ford 6F35 automatic transmission

[tamedcowboy]

I've got a 2010 Mercury Milan Premier 3.0L V6 with the 6-speed 6F35 automatic transmission. I've owned it for a month now and it has 37,000 miles. I've heard bad things about the reliability of the transmission, and wondered what I could do to increase its longevity. Factory recommended maintenance says to change the transmission oil at 150,000 miles, but that seems really long. Also, would Lucas or BG additives help extend its life?

 

[CarbonSteel]

As opposed to adding 3rd party fluids that may or may not do anything (or worse cause harm), I would just shorten the OCI on the transmission fluid and filter and rest easy.

 

[RF Overlord]

Unfortunately, Ford's version of the 6F35 is nowhere near as good as the GM version. Expect to have issues with it. Don't add any miracle-in-a-can junk. Changing the fluid every 30,000 miles will at least give you all the longevity you're going to get.

 

[tamedcowboy]

Thanks, I think you're probably right. I sent off a transmission oil sample to Blackstone last week. I'm really curious what they say. I'm thinking for the 37.500 mile service I may go ahead like you said and flush the transmission just to be safe.

 

[SwampSurvivor]

My parents 2013 with that transmission recommends trans fluid change at 30K miles.

I've heard the first few years had problems but after that - they seemed to get it right.

 

[demarpaint]

I was told the same thing about the transmission in a Ford Aerostar I had. 212,000 miles later I junked it with the original tranny in perfect working condition. I ignored the service intervals for the tranny and dropped the pan and filter every 30K miles along with a fluid exchange. Early ATF fluid changes and shorter intervals will never hurt a transmission.

 

[SwampSurvivor]

Originally Posted By: demarpaint
I was told the same thing about the transmission in a Ford Aerostar I had. 212,000 miles later I junked it with the original tranny in perfect working condition. I ignored the service intervals for the tranny and dropped the pan and filter every 30K miles along with a fluid exchange. Early ATF fluid changes and shorter intervals will never hurt a transmission.


And a transmission cooler. When my parents escape turns 50K (and the warranty expires), I am going to have them install a transmission cooler.

The Mercon LV fluid is not cheap!!!

 

[panthermike]

When we had a '10 Fusion with that trans, the plan was to change the ATF every 25-30K for the life of the vehicle. Got rid of it with 44K for multiple reasons though. I also added a bottle of LG Red.

Change the fluid every 30K, that's about the best you can do. Also at 37K, it likely hasn't been changed. So I would go ahead and do that. Use Mercon LV or my preference Amsoil Low-vis ATF.

 

[Jax_RX8]

I have a 2012 Ford Fusion with the 6F35 transmission. This transmission is known for flares (free spinning), hard shifts, and being very hard on trans fluid (shears it and turns it dark very quickly). There also seems to be a lot of failures of this trans in the 75k mileage range. The Ford fluid (Mercon LV) seems to work well in other ford vehicles, but does not hold up well in this transmission.

Having read this on other forums right after I bought the vehicle, I decided to switch to Redline D6 at 10k mikes and did 2-3.8 quart fluids swaps (oil evacuator)with a short drive in between and have done a 3.8 qt swap every 10k miles since.

I noticed an immediate change after installing - no more flares or hard shifts after a few hundred miles as the trans and programming got used to the new fluid.

I now have 45k miles on the vehicle and it shifts great with no issues - I have also noticed a reduction in the darkening of the fluid over time as I think the RL D6 just holds up better to the demands of this trans.

D6 is not cheap, but I fully expect to get 200k out of this transmission now. Hope this helps those with the 6F35 to get better performance and mileage out of this temper-mental trans.