My owner's manual for my 03' F150 is a little unclear: It's got the 4R70W, and it uses Mercon V, but in the manual it lists every single transmission that uses Mercon, like the 4R100 and others to be changed every 30,000 miles, but ONLY says to change the fluid on this transmission every 60,000, but that's only if it's been pulling a trailer. It was one of those "exceptions" made.

My question is: when the heck am I really supposed to change the transmission fluid?

Thanks,

Rad

 

With the 4R70W, I wouldn't let it go more than 30K between changes, and probably 20K is better.

Mike

 

I did mine at 40k and got it flushed from the dealership.

 

IMO you need to take some of FORD's service schedules With a Grain of Salt & use some judgment by considering just how hard of use the tranny has had & what your long term plans are. Heavy hauling, lead foot, loads of stop & go driving can all contribute to severe use, whereas mostly fuel consumption conscious, virtually unloaded, passenger cruising the open roads equates to gentle use. Relate this spread to time as well when you plan, you might want to change after, say 5 years, regardless of miles. If you intend to keep it forever you would opt to change more frequently-instead of less. If it works perfectly & you're gonna trade it out shortly you might let the next owner ask the Q.

Obviously if the fluid is: dropping level, discolored or bad smelling you'll want to service the tranny ASAP. Usually dropping the pan, draining the converter, flushing, changing a filter, new gasket to seal it up & fresh fluid.

 

I did mine @ 50K. Had the dealer power flush it. I tow some myself, usually around 7K lbs.

 

im with LX, every 50,000 miles. i do it myself, just drain, change filter and refill. no flush.

 

I have 4R70 as well. I change fluid in transmission and torque converter every 30,000 miles. Dont know if you have a TC drain plug in an '03 though.

 

At my work, we work on 1000's of f series and we do tranny and fuel filter changes every 30,000 miles.

 

With the problematic torque converters in this transmission, I personally wouldn't let it go any more than 30K.

Mike

 

Wow, my dad has a buddy whos a real good mechanic that we take our stuff to if we need work done that we can't do and he has a guy working for him who does strictly transmissions and hes "supposedly" real good at it and he told us since its never been changed to not start changing it now even if you do it on a strict schedule, btw my truck has 160k miles on it, from what you guys are saying i guess its well overdue to be changed huh? What do yall think, should i flush it and change it, what fluid do i use, i guess the Mercon V? Btw its a 97 F150 4.6 4x4, don't know what transmission i have..
-sorry for hijacking this thread lol-

 

it amazes me the number of people who say if a transmission is shifting fine, dont do routine maintenance on it ????????? if you engine runs o.k., would you just skip the oil change? what sence does this make? what normally happens is people do not do the oil change, then at 120,000 milels the trans starts having trouble, so they change the oil and when the trans goes out at 125,000 they blame the oil change.

 

so i should go ahead and change it then? my transmissions seems ok, it has bewn shifting a little rougher lately though

 

I just bought an 01 Screw with 84k on it, the fluid is dark, but not burned. Trans shifts fine, but I am going to change it soon. I had 164k on my 96 with the 4R70W trans, and I changed it every 30k, including draining the converter too. I think it's cheap insurance, because a rebuild is costly
Rich

 

a "pressure flush" might break up some hidden sludge and get in the valve body or spools. thats something to think of... draining and refilling can only be a good thing. any crud or contamination that drains out and is replaced will lhelp. the trucks prior to 2001 have a drain in the bottom of the converter ( 4R70)

 

I've had mine flushed 3 times (twice at dealer, once at IffyLube), probably a fourth time in there somewhere....I have 99k on the clock now.
next is a pan drop, filter change, drain bolt install and refill with Amsoil.

Can't hurt for you to do either....watch out for the growing group of "If you flush your tranny, it'll ***** the bed"

Dealer still recommends it....doesn't make it right, but I still have some faith in FMC.