Dex/Merc in place of Mercon V

[FPGT24]

Anyone using Dex III/Mercon in their Explorers? I buy alot of Explorers at auction and sell them on my car lot and have had to change transmission fluid on many of them. I started using Dex III/Mercon in them after I have had issues with Mercon V. The few Explorers I kept around for myself that I put Mercon V in developed nasty torque converter shudders and slipping as well as hesitation. The SOHC Explorer i use to tow vehicles with had what I thought was a bad transmission when I first purchased it, as the transmission would slip, the O/D light would flash, the torque converter shuddered and locked up pre-maturely, and it hesitated often. Got ahold of the former owner and he said he had put Mercon V in it a few years back. Since I got it for only a few hundred bucks I was like F it i'll see what happens with Dex III/Merc, if it fries it it fries it I wouldn't care. Turned out to be an excellent decision. I ran TRANS-X through the tranny for a few weeks, then changed the fluid/filter with Dex III/Merc, and what do you know, the transmission shifts like new and all the issues including the torque converter shudder and pre-mature torque converter lock-up all stopped. My business partner/backyard mechanic has told me on numerous occasions that all his mechanic buddies have told him that Mercon V is garbage and that it will fry any transmission or transfer case you put it in. I have never done a fluid change on a V8 explorer, all of them were V6 equipped, but I'm about to do a fluid change in a V8 one so i hope Dex III/Merc is ok for in those too.

 

[CDW6212R]

The Mercon V is better for the later transmissions. It is a "slicker" fluid and the later vehicles are designed for it. I'm not sure how negative it is to use the older Mercon in them, but that is a risk. I'll let someone with more information about the affects of using the older fluid.

BTW, there is an additive from Lubegard which is made specifically to use/covert Mercon to Mercon V. I have used it and I still have a bottle of it that I may never need. Most people know Lubegard as the best trans additive brand, they make very good products. I tried that successfully in my 99 SOHC Explorer, it worked fine. I did it to save a small amount of money, since I still had several quarts of the Mercon then, and I was going to buy a Lubegard additive anyway.

The issues you have had with your vehicles are most likely related to poor maintenance, plus that they are the weakest V6 trans. Those need some extra care, a VB kit for one. Search here for threads about the 5R55E trans, especially the pre-1998 models. Good luck

 

[FPGT24]

I'm a big Lubeguard fan, I have only used the black bottle but it has done wonders. I'm about to put some in my 5.0 after a fluid change as it has a torque converter that slams and shudders the worst I have seen in any vehicle. I've been dealing cars for quite a few years and in my personal opinion I think the 5R55E is a very good transmission when you keep the fluid changed. Most issues with them are valve body related and there are new valve bodies on Ebay for 200 that solve the issues (as i type this my one buddy's 99 explorer is in the shop getting that $200 valve body installed). It's a rare occurrence that i deal with Explorers older than the 1998 models, as they are harder to sell due to being older (people are weird lol).

In my 98 SOHC that I use for towing, I changed the filter and fluid, drove it for bout 1,000 miles, then i drained the pan again and replaced it with new fluid along with a bottle of lucas. A bottle of black Lubeguard is being added as well and im installing an external trans cooler. I know most people say dont use Lucas unless your tranny is on it's last leg, but i put it in because it's known to keep the transmission temp down, and when im towing vehicles constantly with this explorer i cant have the trans overheating.

 

[Centaurus5.0]

There is a definate quality difference between brands of Mercon V. I bought some Castrol GTX Merc V when I was in a pinch and it smelled like gear oil and was dark dark red. Didn't want to use it, but didn't have a choice at the time.

I only use 1 of 2 different brands when I have a choice. Motorcraft or Amsoil

With Motorcraft Merc V I add a red bottle of Lubegard and some Archoil. With Amsoil ATF I still put in a bit of Archoil.

If it still acts funny with fresh Motorcraft, the clutches/friction material are probably burnt pretty bad. Or maybe solenoid issue?

Also, I don't know about the 5r55e's but the dipstick can be hard to read in a 4r70w. 1/2 a quart low can do funny things.


.02

 

[CDW6212R]

Check the level multiple times, flipping the dip stick each time. I've found that one side will read much more accurately than the other. You just have to alternate it to figure out which is the best side. I don't check the ATF enough to learn or remember which is the ideal side of the dip stick.

The solenoids are the weakest links, not the fluid. And the EPC is critical in the 5R55E, plus expensive(it was $100+). The 4R70W doesn't need much beyond the basic solenoids and maybe a couple of Sonnax upgrades given the mileage.

The 5R55E needs VB modifications when brand new, every VB kit and Sonnax upgrade improves the trans lifespan. Even the case is weak in a way, some gaskets blow out from the long and deep case passages moving/vibrating, due to normal pressure changes. I've never fixed that or read of many who have, but Sonnax recommends it(installing/jambing a set screw down into two specific passages in the case. It keeps the case walls from moving they say, I haven't had that problem or read of reports of results or tests. They are great when working properly, but more likely to develop issues.