Replacing Mercon with Mercon V - Can they mix?

[drew999999]

Ok guys. Just stopped down to the local Autozone to pick up some Mercon V and a filter kit to do the tranny and had a parts guy give me a hard time. I have a 97 AWD, 5.0, 4R70W. TSB says that Mercon V is now the stuff to use because straight Mercon is ending production on July 1. Parts guy had no clue. He kept saying if I put this in my tranny, it'll fry. I know he's full of it. Dipstick says use Mercon (not SP or F or III)

My question is whether the Mercon that is in the tranny has to be completely flushed, or can I drain the pan and converter, replace the filter, fill up and go? Will the bit that is in the cooler harm things? I've read that it's okay to add Mercon V to trannys that have Mercon, but not the other way around? How true is this?

I'd just do the flush, but the current fluid is still nice and pink, and I wouldn't know when the old stuff is completely out without going through tons of fluid. I'm just doing this drain/fill to see if it may help the 2-3 stutter that seems to have developed and also getting ready to tow my boat about 6 hours in a couple of weeks. Any info from the pros would be great.

 

[Turdle]

OK, now I am cornfused-
I thought that Ford was dropping the MerconV classification, because all mercon fluid now qualifies it---in other words they claimed they no longer manufacture lower quality fluid. It has been a while since I purchased any, however I did read the label on a bottle of new stuff, which claimed it was for ALL MERCON applications, specifically "mercon V standards"

 

[drew999999]

Here's the TSB that I'm referring to...

http://v8sho.com/SHO/06-14-4.pdf

Looks like Mercon V for everything... but to make the switch from the older stuff, do you have to do a full flush or will a partial be fine?

 

[CDW6212R]

You can mix it, but it's just like mixing regular and premium, the result is based on the percentage of each. You should want as much of the Mercon V in it as possible. There will be a small amount left in the cooler, but qyuite a lot stuck up in the valve body.

I'd suggest draining the torque converter, there's a gallon. Remove the cover from the front of the trans, and drain the TC by turning the engine by hand to get the drain plug at the bottom, etc. I woulod find a local trans parts store, and buy the Lubegard additive that they all carry. Buy the one for Mercon V, and buy at least ten quarts of Mercon V.

Maybe later you can order synthetic fluid and change that in next time.

You are correct, the Mercon fluid is obsolete, Mercon V is much better. Ford will obviously make a better fluid again, so there will be a new highest standard soon. Good luck,

 

[Glacier991]

Excellent advice Don, as usual. The lubegard is a small conainer so it will not replace a quart of ATF. Use Lubegard Platinum if you go that route.

 

[drew999999]

Thanks guys! I'll pick up some LubeGuard today before I get started. I've had this truck for about a year and it's about ready to roll 100k. Been going over it and it drives and tows almost like a new truck. The MAF trick should almost be considered a mod since it upped my mpg by about 3.

It's kinda hard to believe that the Autozone guys are giving such bad advise to their customers. Their computers don't even list most of the parts for the AWD models so I have to get them to look up most engine parts under the 4wd/5.0L. They argue with me about that one also. Go figure. I was gonna fill her up with the Mobil1, but could only find about 7 quarts in most of the city. They did have a Coastal brand at one of the parts stores that said it was a full synthetic, but I wanted to stick with a name brand since a new tranny is big $$$.

Thanks again for the info guys.

Drew.

 

[CDW6212R]

Do the AWD transfer case also, and do it often. They only hold about as much as a rear diff, or less. Stick the Mercon V or synthetic in the AWD too, there are two plugs on the backside, fill/drain. Good luck,

 

[Izb]

http://www.explorerforum.com/forums/showthread.php?p=1969827

 

[Jack Flash]

Thanks guys! I'll pick up some LubeGuard today before I get started. I've had this truck for about a year and it's about ready to roll 100k. Been going over it and it drives and tows almost like a new truck. The MAF trick should almost be considered a mod since it upped my mpg by about 3.

It's kinda hard to believe that the Autozone guys are giving such bad advise to their customers. Their computers don't even list most of the parts for the AWD models so I have to get them to look up most engine parts under the 4wd/5.0L. They argue with me about that one also. Go figure. I was gonna fill her up with the Mobil1, but could only find about 7 quarts in most of the city. They did have a Coastal brand at one of the parts stores that said it was a full synthetic, but I wanted to stick with a name brand since a new tranny is big $$$.

Thanks again for the info guys.

Drew.

I'm sorry to admit it, but I once worked for Auto Zone. It was between teaching jobs and it only happened once....lol.

That aside...the electronic catalog used by Auto Zone (and others) is full of mistakes and omissions. When I did work for them, there was a procedure to notify the head/whatever about those catalog problems. I submitted the same problem monthly with no correction made. I gave up trying to get corrections done to the dumb catalog.

What's the automotive world gonna do when all the real partsmen die or retire ? I guess what the local Auto Zone here does: hire stock boys from Wal Mart....their only qualification is that they drive a car...lol.

end of Saturday night rant.