Originally Posted by 69GTX
Originally Posted by Dave9
You're going wrong somewhere, maybe thinking of small vehicle Ford Trannys? It should have the 4R70W, an old (circa '93) yet matured design, which typically goes 200K mi without any fluid change, and was also used on F150's capable of >5K+ lbs towing (granted the rear diff ratio matters here too).
It's over spec'd for a Grand Marquis. A more common recommended service interval is every 150K mi or 30K under severe/heavy-towing conditions. 25K for regular driving a Margquis? No way, you might be thinking of Honda.
I'm certainly not wrong. I've owned a dozen big Ford and Merc sedans since 1984. A couple of them I got used at the 50K-75K mile point. And I wasn't yet up to speed on changing trans fluid as often as I should have. I believe owners manual on these has ALWAYS been 25K-30K.
Nope. By 2004 it was highly likely that Ford considered the factory fluid, a lifetime fluid. Nothing large(r) in Ford's passenger vehicle fleet had 25K-30K by the turn of the century except severe duty loads.
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After losing 2 transmissions on my earlier Crown Vics at 75K and 125K respectively, I went to a strict 25K-30K regimen. Never lost a big sedan trans early on again. 150K mile fluid changes on a big Ford sedan? That's nuts...unless you want to replace the trans by 75K-125K miles. I prefer to go 200-250K miles. The fluid is pretty beat up by 25K and heavily sheared down if you're using non-synthetic Merc/Mercon V. 25K miles on most regular Merc/Mercon V's and I'd bet the viscosity has sheared down from 7.4 cSt @100C down to 5.2 or lower. Being below the normal range of Mercon V specs should be reason enough for changing it by 25K miles.
I can't help it if you or a former owner drove abusively, but the 4R70W has been put in millions of vehicles and did not have (even its share of) problems by 200K mi. Quite the opposite it was one of the most durable trannys out there, and again, it was even used in F150's with > 5000lb towing.
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Fwiw Ford's recommended trans fluid change for the 2004 GM is 30,000 miles. A typical life for one of these is probably 125K-175K miles.... assuming you change the fluid as recommended and don't pay much attention to your driving habits.
No, it's not. Some Ford trannys such as 4F50N or 4F27E had 30K. They were in a lot of Taurus, or 4F27E in Fiesta, Focus, and some Mazdas.
If you want to go to the extra effort, you can do that with anything but don't pretend this is important or unique to the 4R70W because it's the exact opposite. Changing fluid in that every 30K would be like changing fluid in most other vehicles every 8K. In either case it would be excessive.
Show me where Ford, not someone else, specifies 30K mi for 4R70W? It's not in the Owner's Manual, which refers to the service guide, which only specs to CHECK, not replace it except on the two lesser trannys mentioned above. This is common in many different Ford Scheduled Maintenance Guides, that lesser trannys get 30K but not the 4R, E4OD, then onward with newer 5R.
The difference is these were not light duty trannys to improve fuel economy, rather built like tanks for heavy load.
You never lost another Crown Vic, Marquis, SUV, Truck, etc (many different vehicles prove this) sedan tranny not because you changed fluid excessively but rather that they trannys got better, good enough that the manufacturer themselves did NOT specify a fluid change, even after their warranty liability ended. If they had any concern it would certainly be BEFORE the 60K warranty ended. If you are pushing a car harder than a truck, yeah you might have all kinds of problems and burdens.
Don't do that. Do change it at least by 100K, but let's not get silly about excessive cost and burden for something Not Worth Much Money in the first place. Do that for your new car, sports car that you drive hard and put away wet. Maximizing burden on an old domestic freight train of a car is senseless.