I will be changing Transmission Fluid in a 2013 F250 with the 6.7,I just bought,with 140,000 miles on it! My question is,can I change fluid and filter
using Mercon LV not knowing if the existing fluid is synthetic or not??? I don't have the previous owner's service records,so,I don't even know if the
fluid has ever been changed!!! Planning on a fluid and filter change now,and,another fluid & filter change the 1st of Aug. before pulling the toyhauler to S.D.!

 

Yes, it shouldn't be an issue. I would suspect that the fluid has most likely never been changed and typically if you purchased the truck from a "reputable" dealer they should have done services on the truck prior to resale.

 

Just keep in mind…drain and fills don’t replace all the fluid.


if you do a chart to compute how many drain and fills it would take to replace 100% of the fluid the chart would be pretty complex..I stopped trying to calculate it fully at 17 drain and fills.

 

I would suspect the fluid to have the proper spec'd fluid in it

Also to have not been serviced.

To help you spend some more money, the transfer case and both differentials (if 4wd) need to be changed too.

 

Since you don't know the service history of this truck, and it's a good assumption that the fluid was never changed, go with Motorcraft Mercon LV for sure...

I'd recommend this: do one drain and fill. Let it run a little bit... then do a second drain, drop the pan, clean the factory magnet there and pan, replace filter, re-install the pan with the factory reusable gasket and fill with another 8.

You don't need to get all the fluid out. Revitalizing the add package with fresh fluid will work. I've done drain and adds to my trans at 31450, 67147 and 91647 miles with a filter change at the first drain and filter change at the last one. Truck's at 123,400 miles now.

Yeah I know Overkill... but two Ford techs on You Tube say to do drain/fills at 30k miles. I did a analysis on one of them, I'm thinking the last one at 91k miles and the fluid was in great shape (was less than 30k miles on it when analyzed). I won't go past 40k miles on this last drain/fill but when I do drop and add 8, I'll take a sample and send it in... I also have have high temp rare earth magnets in the factory trans pan also.

You'll know the fluid or filter haven't been changed because that factory donut magnet in the pan with have a lot of silver "fuzz" or clutch break in material on it... if it's not bad, then the pan has been dropped and cleaned before because mine at 31k miles had a lot of crap on it...

And if you do buy two cases of Mercon LV and do two drains and fills, you'll have enough enough left to drain/fill the transfer case as well...

 

I used to change at 40K also until I removed the Thermal regulation valve from the Transmission and added a bypass valve. I tested my Trans fluid at 40k and 60k but will probably change it at 80k only because I want to change the filter. I added a thermal valve inline @ 160F, I really see temps over 180F under heavy load.

 

I just daily drive my truck... No heavy loads here...

Old habits die hard for me... My first Ford, in my sig, was used as a daily driver and plow truck in winter... And she sure plowed through some crazy storms here in Buffalo. I heard horror stories of the E4OD giving up the ghost early in its life so I applied my overkill mentality to it. I won't go into detail but I had a two way valve set up in the return line back, after the two coolers I installed, and I would do a drain (truck ran, somebody in the driver's seat, shifting thru the gears until it started spitting, shut off, refill and do it again.... That trans was still running although tons of glitter in the fluid when we pulled it for the core at 91k miles and tons of pushing crazy lake effect snow...

So yeah, it's a little tough for me to go way out on the trans fluid but we'll see how far I go... Like I said, after this upcoming dump and fill, no trans filter as I did it at 91k miles, then the next one I'll do the B&M pan and SBE braided trans lines as well.

Appreciate the input brother...

 

Mercon LV is a synthetic fluid, hard to get it as thin as it is without a synthetic base stock. It is also pretty hardy stuff, can handle pretty long intervals. I dropped the pan on mine at 84k, my guess is it was the factory fill and refilled with 7ish quarts of LV IIRC. I will probably drop the pan every 50-60k miles just out of habit and to inspect the magnet etc.

 

Same is used on the Ford Flex 6 speed with Ecoboost. 176K miles on the original fill, drained out the case, added 6 quarts, good to go. It was darker than new, but no tinge of brown, which is a good thing. It had a slight 6th delay when cold that went away after the change.

However, if you want to do a complete fluid change, find a 3rd party that has the trans fluid exchange equipment. They will hook into the transfluid cooler plumbing with a full fresh load of fluid that will replace the fluid existing in the trans and torque converter while running.


You know, for $500, its really not that expensive to buy one and do them myself, especially with 6 vehicles.