I havecan 01cnavigator with the 4r100 transmission in it 4x2 . I hit something in the road and hit it just right so that my trans cooler lines got ripped out and lost almost all the fluid which was not the end of the world had it 5owed back to my housecand had a buddy of mine replace the lines and he swore up and down that the cooler Ines didn't run thru the radiator cause it has an auxiliary cooler on it and that it would be more than enough to keep the fluid nice and cool in the the south during the summer I thought ok he has fixed my **** on multiple occasions and knows what he's talking about well long story short I put mercon 3 instead of 5 and the Trans over heated several times and went from shifting fine to having to manual shift buy still ran fine to I have reverse and it goes unto drive but doesn't move forward I changed the the fluid and filter and it put in drive and moved fora few feet but then stopped and nothing should I gludsh all the fluid out and make sure it has all new fluid cause that is when it seems to wanna move is ehen it has fresh new fluid in it. Help I know about engines but transmissions I'm not to knowledgeable about i mean as far as diag nosing the problem for say, please c someone help me here and tell Mr that the Trans isn't completely shot and toastoh and I have the cooler lines running as they should now thru the radiator to aux cooler. And I just want it to drive even if it's ****ty just move so I can get back and forth to work so I can afford to get it rebuilt. Please someone give me some hope here please

 

This could be bad. I don't know the specifics, but I've heard MANY times over the years about people putting Mercon 3 in a trans that was built for Mercon or Mercon 5 and frying the trans in a very short time. At the very least, I would drain the trans and refill with Mercon 5....this includes draining the torque converter. It has to be drained separately from just dropping the pan. Also change the trans filter, and try to flush the cooler lines and coolers. You have to get ALL of the Mercon 3 out of there. You might get lucky, but I wouldn't bet my pension on it. Good luck !!!!!!!

As for the line routing, the lines run from the trans, into the radiator, to the aux cooler, back to the trans. I'm almost certain the rear most line is the "line out" of the trans........but I would double check that.

 

What fluid did you really put in it? There has never been a MERCON 3 fluid. It never existed.

Even if you did put the wrong fluid in it, that won't prevent it from moving. It may shift poorly and not live long, but it will move. How much fluid did you put in?

 

I assumed he was talking about Mercon lv...although I know that's not a "3". I've heard a lot of people call it that.

 

I've heard a lot of people think MERCON is MERCON 3. It isn't, And MERCON was discontinued in 2006, good luck on finding any of that still on the shelves. And I've heard the argument that DEX/MERC is the old MERCON. Maybe it is and maybe it isn't. DEX/MERC doesn't meet ANY specifications. Are you feeling lucky?

 

lol...As far as I know, I bought the last 5 gal of true Mercon in existence back in 2020. I've been told by multiple people that claim to have been ford teks of various depts that Mercon 5 is the closest sustitute to plain Mercon that can be gotten,.

 

When MERCON was discontinued MERCON V was reformulated to be compatible with older transmissions that used MERCON. MERCON V *IS* the replacement for MERCON.