Oh, and personally I tow a double axle, open trailer with a Suzuki Sami (heavily modified, not street legal, running 33's, soon to be 35" tires, once the 33s wear out!) i tow this up hills you wouldn't want to drive a 2 wheel drive anything! and it does its job perfectly, not much struggling and I am pretty much bone stock 4.6! Just get a Tranny cooler with an e-fan and a mag-hytech tranny pan!

 

Let's compare apples to apples - you have done mods to your engine and tranny. I highly doubt the cops and cabbies bother to do any mods. If your truck were bone stock and you treated it like that, I'd guess your chances of blowing something up would be a lot greater.

 

First, Amsoil is not $9 per quart. If you are signed up as a preferred customer, it is about $6.40/quart depending on how much you buy. For a full flush, you should think about TWO 2.5 gallon containers. That is 20 quarts and will be more than enough for a full flush.

RP is roughly $8/quart.

With either, towing or not, there is no need for a full flush every 30K miles.

You must remember that many small companies like Royal Purple will make their transmission fluid Mercon V compatible but will not be willing to spend the $250,000 to get it licensed as "Mercon V."

Nevertheless, RP works just fine in the F150 transmissions requiring Mercon V. In our group of 11 trucks, all 2002 and later models, all run either RP or Amsoil and have had zero problems. Combined miles is well in to the 6 figures.

I've read threads here where some do not like RP or Amsoil or Mobil 1 synthetic ATF because it caused cousin Vinny's piece of crap tranny, not well maintained, to blow up or leak like crazy.

If you do it right from the beginning, you'll be doing your truck a favor. Take a look at all the threads where people are having multiple problems with their transmissions and they are running Motorcraft mercon V. Bottom line is, maintenance is the key, no matter what you use. But I prefer synthetics. And FWIW, Royal Purple is the ONLY ATF that just about matches Motorcraft Mercon V chemically. RP has almost as much Boron. All else was almost identical.

 

Dr. D... WELL PUT! thank you! and glc, you have a point. I wouldn't recommend doing too much bone stock... unless your bone stock with the towing package. The only mod I have is the Tranny cooler ( Troyer Performance) and the Tranny pan from Mag-hytech... I would say thats not a whole heck of a lot. And like I said, that old Ranger used to tow a 20' travel trailer, with four people crammed in and the bed loaded down. So, you have a point... we all recomend some mods before towing... but you can tow, stock with more up-keep and a closer eye on ALL the guages! I didn't mean to compare him to me, i was just giving some examples of the little engines pulling big loads with no problems. We Ran 120k on the Ranger, sold it to a family friend who kept it for another 40k or so... so we didn't destroy it towing that big ole trailer, loaded.

 

i agree 4r70w is still considereed a light duty automatic. if your hauling alot you better get a coooler and dont slack on the maintenance. i almost bought a 99 ram instead but then remembered the tranny horror storys. glad i went with the 150 instead.

 

If it's the same, why is it better? I get motorcraft fluid for about $35 a case Roughly $3 a quart. If I buy 14 quarts of Motorcraft MerconV I just spent about $41. If I buy RP I just spent about $112. I could have bought a hayden 679 with the change and have done way more improvement to my trans, and still had enough for lunch at wendy's. Stock coolers (including the tow package) suck. A good cooler will do more for your trans than any fluid can do.
Alan

 

Full synthetic *IS* better - but whether it makes enough difference to make it worth the additional cost is a decision only you can make.

 

It's not the same. RP is a full synthetic. MC is not. But their chemical additves are very close, meaning, RP is closer to MC Mercon V than any other ATF I had tested. RP will last longer, probably double the miles than MC mercon V, and even longer with a superior cooler as you mentioned.

IMO, a full synthetic ATF is money better spent than a synthetic motor oil.

 

You seemed to miss the point I was making. A good trans cooler will do your transmission more good than $100 worth of high rent fluid.
Alan

 

No. I knew what your point was. My point is, that the factory cooler with a good synthetic may eliminate any perceived need for a high dollar aftermarket superior cooler to begin with.

It's all choice. My choice is the better lubricant.

 

So you think a 200 degree trans with syntethic fluid is better than a 160 degree trans with conventional fluid? OEM coolers were never intended for extended life, they just want to make it out of warranty. Personally a $65 cooler and regular maintenance is a better bet IMO.
It seems this stuff comes up all the time. Some people are convinced that synthetic fluid must be something special because it costs so much more. I fall under the non believers. I believe in GOD, I believe in preventative maintenance and I believe in transmission coolers. On the other hand I onyl got 220,000 miles out of my truck without any major failures. Maybe I should have run synthetics and pusshed it for twice that.... Maybe a few less burnouts and not working it like a mule would have helped too. What can I say I abuse my machines on a daily basis and expect only the best from them. With proper maintenance I get a life expectancy up to my expectations. If I built a full blown race engine I would run nothing but synthetic oil in it. If I had a trans that for some reason made excessive heat with no other way of controlling it I would run synthetic fluid in it. I still think synthetic diff oil is trouble no matter what. The transmission was designed by the manufacturer to use a certain fluid, they did it for a reason. They put synthetic oil in superchargers for a reason. The only thing I will say that I am always for synthetics in is the brake system. Synthetic brake fluid is just plain better... It abosrbs less moisture and extends the life of the seals. not to mention the heat handling properties of it in comparison. Boiling brake fluid is bad. I demand serious operation of my brakes. I get about 75,000 miles per set on the front of my truck at which point the pads are half worn and the rotors are rusted out. The rears last about twice as long.
Alan
Alan

 

Then why does Ford *require* it?

 

No, and I'm not convinced that those numbers are accurate across the board either. Cooling of any fluid is beneficial, but the synthetic will run cooler on its own anyway.


I cannot think of any post I've ever done that stated or remotely implied that a synthetic is better or special because it costs more.


I have never argued that you cannot go "well into the miles" using OEM or similar fluids. I'm not sure why that keeps coming up. That seems to be the "go to" arguement for not using synthetic stuff.

I take several things into consideration. For example, in our Hondas, the Z-1 ATF is $6.88/quart at the dealer----$7.32/quart after tax. Can't buy it anywhere else around here. Amsoil (Z-1 compatible) is $7.10/quart delivered, sometimes cheaper depending on quantity ordered. The color of Honda Z-1 fluid reminds me of a glass of Pepsi after 30K miles, and that is "normal" according to some Honda techs, and some Honda forums, even though it is not.

When we purchased our 2 most recent Hondas, I had been doing a drain/fill on the van about every 20K miles and the fluid still looks quite dark, and Blackstone indicated that all of the fluid needs to be changed.

So, I put Amsoil in both. The van now has 38K miles on the current Amsoil ATF. I loosened the drain plug enough to leak 2 oz for analysis. Color: looks new, bright cherry red. Results pending.

As far as Mercon V in the F150, well, I've seen good and bad results even with regular maintenance as suggested by the owners manual. And both trucks are used to tow 10' trailers with commercial mowers. Both trucks have aftermarket coolers.

In short, I've witnessed more problems with transmissions using spec dino ATF and a good cooler than a stock cooler with synthetic. In fact, in 15 years of owning a truck or 2, I've never seen or had a problem with a tranny that used a synthetic ATF. But I realize my personal accounts will be different than others. Our perceptions are based on personal experience.

So, I'm a believer in the synthetic ATF. And in my case, it's cheaper and lasts a helluva lot longer than that Honda sh_t. As far as the Mercon V, well, since I already buy the synthetic and have it delivered, it's not worth it to me to save, what, maybe a couple bucks per quart, when I'd have to change it twice as often? Doesn't seem to save me any money.

 

doc, not that you'd ever want to use it, but fyi, I've had really good luck with the Castrol multi-vehicle import ATF fluid. Stays cherry red through my 30K or so changes on my Odyssey. Smooth shifts at a good price. 170K+ miles on my transmission, now.

http://www.castrol.com/castrol/secti...tentId=7028224

 

The OEM stuff is semi syntehtic and is all I will use in a traction lock diff. I have heard too mahy horrow stories about noises and failures from ford 8.8's using other fluids. Personally I have never run them or had the problems. I use standard 80w-90 that I buy for $22 a 5 gallon bucket in open diffs and the expensive but worth it 75w1450 motorcraft in traction locks.

Doc I never said you said those thigs it just seems ths stuff comes up often and I just don't understand the desire. A cooler is a one time purchase, the fluid still needs to be done every 30k. Seems like the cheaper and more effective solution to me.
Alan