The father of one of my friends recently made this unusual suggestion: he told me to drain the trans fluid in my C6 ('88 F150) and replace it with Mobil1 or Pennzoil 0w30 fully synthetic motor oil.

This man has been a professional mechanic off and on for the past 35 or so years. I admire his knowledge and skill very much, and highly value his opinion. He runs synthetic motor oil in his '94 F150 with AOD, and has for at least a year or two. He says that a good friend of his who rebuilds trannys does this with every rebuild he performs. He also said that his trans has never felt smoother or seemed to engage more positively than it does running synthetic motor oil.

I was wondering if anyone else has heard of this practice, and/or has tried it. I'm a little bit skeptical, but have trouble doubting this man's experience. He's helped me over the past 14 or so years on various personal automotive projects, and he has always been a genius on everything we've done. He's also a die-hard Ford man, with his truck, a nice custom '74 F100, and a cool '61 Falcon Ranchero, (and his wife drives a Lincoln).

Thanks for any info you can give me.

 

Well,with all due respect to this man,I would think it would be safer to use a Mobil 1 ATF rated for that application instead of motor oil.Just my two cents.

 

That's kind of what I was thinking. If anyone else out there has heard of it done or has tried it, let me know.

 

I guess this man's experience beats all the car makers and oil companies, millions of dollars of research and thousands of research scientists. After all, the car makers and oil companies would proably only get sued with multiple class action lawsuits if they put the wrong oil in their machinery.

I beg to differ. I am NOT an EXPERT, and no one pays me to know anything about cars, and you should not believe everything I say, but from reading and understanding a little about business, I am fairly sure, if Ford tells you to use Mercon xyz, then you probably should.

I love synthetics, but I use the right type synthetic for each part of my car. Yes you probably can use synthetic oil in a tranny, and probably it will work fine, at least long enough that you won't be able to prove that using the wrong fluid caused a failure. You would be amazed at how much abuse modern engines and trannies can take before they blow up.

The manufacturers do their best to achieve EPA mandated mileage, customer required longevity, minimized warranty claims and so on. If they can find a "trick" that helps them meet this goal and which is reliable and relatively inexpensive, they would certainly do so. Afterall Synthetic motor oil is a little less expensive than synthetic ATF or tranny fluid so why wouldn't they use it if their million mile torture tests prove it works. Use your head and think about it. Detroit is cheap but not stupid, most of the time.

Racers tricks, old buddy advice, expert mechanic opinion, can all be good and may work for LIMITED applications, but in general I would go with the organization that invests millions of bucks in research, and then they have to put their name on every product and guarantee it will work for most people.

I have known too many "experts" and seen too many run of the mill mechanics who couldn't think their way out of a shop manual, don't get m,e started. So go with PROVEN experts, or at least a company that is staking their business and reputation on their product. Not saying they don't make mistakes, Firestone for instance, but they get to pay big bucks if someone catches them.

Good Luck, I've been burned a few times too many by "expert" advice, so sorry for my maybe over reaction.

Jim Henderson

 

Well put. Thanks for the reply. I'll go with synthetic ATF if anything.

Thanks,
James

 

Oh, one last word.

You won't go wrong with the name brands. Taking the advice of some one, to use something that is not recommended by the maker is at best a crap shoot. Maybe the advice works, maybe it doesn't.

But the recommended product has been proven over millions of engines and billions of miles, I go with overwhelming experince. The odds are in your favor that it will work.

Good Luck,

Jim Henderson

 

Here's one real answer, not an opinion.

http://www.amsoil.com/products/atf.html

 

I would think that a lot of fluids would work in an automatic transmission for a period of time. A synthetic motor oil would be closer to an automatic trasmission fluid than most others. I suspect this older gentleman doesn't drive a lot and this thicker fluid might even make his transmission work better if he has worn seals. It's all in the details. STP has a notice not to add it to automatic transmissions. Reason is that wear additives like ZDDP have the wrong effect on clutches, you don't want clutches to slip. Motor oils have a number of wear additives. So it can work if you don't have hard loads but I wouldn't expect it to go 100K. If you feel you have to put something in, put in a bottle of Lucas. And that left over ATF, you can put that in your engine.

 

The clutches need just the right amount of friction modifier additive. Old Ford and Toyota automatics used type F fluid that had none. The newest "engergy conserving" motor oils, synth or dino, contain friction modifier. This is why they do not work in motorcyles with wet clutches. But why take a chance? The E4OD is particularly sensitive and needs the correct Mercon fluid.

Jim

 

IF you use the proper rated fluid - and this INCLUDES the proper additives... I have used synthetic fuilds since 1987 now - Amsoil since that was the first major co. to do so at that time.

I have never had a break down of an engine or transmissin, and the one time I purchased a used truck {my last}, when I did a complete auto fluid change I could go up the same hills {with no down shifting} 5MPH than before.

I also do off-road, rescue, and specilized field work {sorry can't say what}.

Of course you must also maintain you auto tranny and even though Amsoil has extended drain intervals, in a transmission I usually still go 30k between fluid an filter changes.

I like Amsoil since they make the proper {and 100% synthitic} fluid for just about every vehicle. Again if you can't get the proper rated fluid {no matter what the base stock} then you will likely have trouble.

 

I think you better buy the old boy one of those clapper on off thingies for his trouble light.

 

I'm no expert either. I do know that ATF is full of detergents, as well as other additives. I know motor oil, whether synth or not also contains detergents. Whether the 2 have the same type, in the same amounts is anyone's guess. Only the folks that play with test tubes and Bunsen burners are going to know that. Now it may well be that synth oil will work in a tranny. Maybe for a long time. Does it do as good a job of keeping the tranny clean, controlling the varnishes that build up over time, etc? Who knows? Common sense indicates that motor oil goes in a motor, ATF goes...you know where. It's not as if anyone is seeing some metamorphic change in the way their tranny shifts. It makes for interesting talk with buddies over a few beers, but when I'm driving home, my tranny is running ATF.

How about running ATF in motor? Now that would make for some interesting conversation:-staun

 

Strange how "prdprdprd" sounds exactly like another of Amsoil's sleazy dealers. It's a shame you didn't post your great experience with that wonder oil in the applicable forum, prd. Moderators there do not look highly upon such solicitation.


Getting back on topic now. You really can't argue with the manufacturer when they recommend a fluid to be used in a product designed by their engineers and developers. The other users have already posted exactly what I have learned over time. When you cross that line into the unproven practices, your expenditure on the alternate method becomes exactly that- an expense. No longer the investment it would otherwise be had you followed the OEM recommendation. Everyone else did a great job of emphasizing this. Of course the choice is entirely yours, but you have to ask yourself if you're willing to take that gamble, if you're willing to potentially get your automatic rebuilt ahead of its time

 

 

Since you are all talking about Auto trans. I have a 2002 f150 120000miles. doing the 2nd trans. filter fluid change. Been using the ford mercron. Parts house said to use Amilie universal synthetic. By not draning the torque converter is it save to mix. Also thought about using Lucus trans.additive for p.m.
thanks