Bucko

I'm getting close to 30K on my 2011 Mustang. It has the automatic transmission, and my question is this; are these transmissions safe for a flush type service? There was a lot of debate on the F150's as to flushing the automatics to get all the fluid out and replaced. Many said it dislodged crud in the valve bodies and caused the automatics to fail within a few months of this service. I had my truck done every 30K (full flush), and the transmission is still going strong at 140K.

The owners manual states to change the transmission fluid at 150K for the Mustang. This seems high to me. I don't want to question the engineers however (learned that lesson), but would I gain any additional longentivity with the automatic transmission by flushing the fluid more often? Is flushing safe for these transmissions? Just dropping the pan and changing that fluid and filter would only gain me a small, partial fluid change, mixing maybe 4 quarts with whatever old fluid is still in the torque converter/valve plate. I also know that these transmissions have no filler tube per say, so it would need to be done by a special device made to flush the system. What fluid did it come from the factory with that makes it suposedly go 150K between changes/flushing?

So, flush is safe, and at what interval for long life?

cdynaco

Well I can't say for the Mustang, but my Chrysler auto says flush & change every 30k - that way crud hasn't built up yet. And those that do so get well over 100k. Those that don't have problems before 100k.

Prob ask Dealer but I would think the general concept applies to any auto trans. Like your F150. Wait too long leads to problems.

Bucko

Thanks. I keep my vehicles well over the 150K to 200K miles range. I've always flushed automatic transmissions at 30K to 35K in other vehicles I've owned. With Fords high milage fluid replacement recommendation, are they using some super synthetic from the factory?

My wifes BMW came with "lifetime" automatic transmission fluid, and they replaced the transmission at 82K. The mechanic there said there's no such thing as "lifetime", (except if you look at it as when the transmission fails!). They specified this because they (BMW) pay for all the fluid changes, therefore the automatic fluid never gets changed on their dime. Good reason why we leased this vehicle; it was a certified pre-owned that had 30K on it with a warranty plus maintenance contract with it.

I'll visit the dealer, but if they say it's not required, should I consider to take it elsewhere for a flush if the mechanics here on this site think it is better off to do? And would a flush be safe for these transmissions? I'm thinking yes if they are done early enough to prevent crud from ever building up.

wanted33

Bucko, be careful which operation you take it too other than the dealer. First, if their like the jiffy lubes, etc. around my area they will say yes just to get your money. Second, at the low mileage on your car you may want to think about the warranty. If problems come up after the fluid is changed by someone other than the dealership will the warranty cover the problem? If you feel better changing the fluid, I'm sure the dealership would change it for you if you ask. That way there shouldn't be any warranty problems. Just my thoughts.

Bucko

Those are good thoughts! Since there is no need on my particular model for a trans cooler, I figure I'd rather steer towards the "too soon" side of maintenance rather than wait 150K. This just seems too long to leave the oil in the transmission. The engine has an extra quart added, and from articles I've read, this allowed Ford to suggest going up to 10K between oil changes. Perhaps they did the same with the automatic transmissions?

I'm early with only 20K, but with the mileage I put on the car, I'll hit 30K in about 2 months.

wanted33

I with you my friend. When I see these recommended numbers it bothers me a little. I'm of the old school, and as you will change mine much sooner. Doesn't cost that much for a little piece of mind.

BigR

What does the owners Manuel schedule say ?

TheReaper

^^^^ This.

Mustang Mafia

270,000 miles on my 98' 4runner (second vehicle, work, grocery store, p/ u kids). NEVER has the transmission been flushed or rebuilt! ! Look around and see how many of these model 4 runners are still on the road. (95-99)

Bucko

As I already mentioned in my post.... it stated 150K, which I think is high, unless they put some real good fluid in the transmission.

TheReaper

Do it at 100k if it makes you feel better, anything less is a waste of money.

Bucko

In reading the owners manual some more last night, Ford does drop the fluid change interval down to 30K if you tow....I certainly don't use the Mustang for towing, but find it interesting that the fluid can go 150K on non towing vehicles, and drops to 30K when towing.

I guess these transmissions (automatic) are tough when used normally. Being old school when it comes to maintenance, I'm still concerned going that long before a fluid change in the tranny.

cdynaco

No way! By then an auto IS fill with stuff. When you wait that long, That's when a flush DOES cause problems.

(I'm speaking from experience. Flushing at 100k was almost impossible. They had to do it twice. Fluid never did run free but they got it to run clear. Tranny was dead within 10k.)

cdynaco

If they say that, tell them to do it anyway - you're the owner. That's way its logged under Ford and there are no warranty issues. Doing something before schedule does not undermine warranty.

I'm with you on every 30k before any gunk gets a chance to build up in the many nooks and crannies of an auto.

Bucko

Good point with using Ford to do it; and I have a 20% off coupon from my local dealer I bought from.

TheReaper

That's total Bull ****. This is not a transmission from the 1960's. The clutch bands in the new transmissions don't create sludge like the old ones. Do some research on ZF transmissions because that's who designed the 6r80. ZF 6HP28

SpiderX1016

I've had a VW follow the same path. They said it was lifetime AT fluid but it started slipping at 75k. I traded it in before it got worse.

I don't believe in flushes though, just a simple drain and fill or drop the pan/filter.

cdynaco

My vehicle is a 2010 - and a 30k flush is recommended in the manual. And if the OP is at 140k in his Ford by doing it every 30k, that's even more convincing to me.
Each his own.

Bucko

On the F150Forum I frequent, the automatics are troublesome. Granted, a truck with an automatic is going to see more abuse than a Mustang equipped with a V6, as it's built to tow, haul, and do things a truck is meant to do. I also expect that this type of transmission is designed to handle this abuse. Yet, the 04 to 08 trucks have a reputation for automatic transmission failure prior to 100K. Those that changed the fluid (flush) had a much higher mileage range then those that did not. Since there is no need for a trans cooler in the Mustang, I wondered how the trans fluid could survive for 150K miles. That's pushing the fluid and it's additives, unless they are using some serious stuff.

Bucko

My concern with this is that it only gets about 5 quarts of fresh fluid in the transmission. They hold close to 12 quarts (11.9).