Mercon/Mercon V Question

[Banjoes]

MY 95 XLT is leaking transmission fluid from the driveshaft seal I think, but it might also be leaking from the torque converter seal.

first, a little background: the original transmission(no leaks) went kaplooey so we took a pull off from a 96 explorer at the junkyard. we replaced the torque converter seal and the driveshaft seal with NEW ones and they put in Mercon V (no other additives) instead of owners manual specified Mercon fluid. I know that Ford says its okay to do this, but I have heard that using mercon v instead of mercon is not good because the seals were not designed to handle it and the fluid will slip right past the seals. I was wondering, did anybody else here have this issue? Or did we do something wrong? (the seals seem to be seated fully)(one of the pictures shows leaking tranny fluid)

 

[SoNic67]

I did add MerconV in my '96 Sable transmission (original Mercon) starting some five years ago. No leaks or bad effects till now.

 

[koda2000]

Mercon is just plain old dex/merc ATF. Mercon V (V as in 5) is synthetic or a synthetic blend made to Ford's spec. I've always heard never to mix the two, not even after a complete fluid change, because it will mess up your seals.

 

[Banjoes]

UH-OH!

I remember when we brought the pull off transmission home it leaked out tranny fluid in my mom's Toyota, it had towels stuffed in it but it still leaked out a considerable amount. But anyway they bought Mercon and filled it up, they did NOT do a flush or anything. But afterwards, my dad says that after he started noticing it leaking he couldn't remember what fluid to put in, so the guy at advanced auto told him to just put in Mercon V.

So my thinking is that the old owner of that 96 explorer (the junkyard one) probably had put in Mercon V and because we didn't do an immediate flush after filling it up it screwed up the seals.

Oh crap! does that mean that we have to do a flush and buy new seals! I want to try a flush first to see if that stops it. Or should I drop the tranny and replace the seals and then get a flush done?

thanks is advanced.

 

[koda2000]

If it's leaking now (whatever the reason) changing back to Mercon will not solve the problem. The rear seal is a piece of cake to change... the front pump not so much with the tranny installed. Personally I'd never have installed a used transmission without having changed all the seals, fluid and filter and cleaning the pan and magnet. You're just asking for problems/leaks. On Fords the trans dipstick usually tells you what fluid to use. I would also drain the torque converter (or flush) the system, otherwise you're leaving about 1/2 the old fluid in there. As newer torque converters don't have a drain plug, one trick is to drill a 1/8 hole in the converter case using a new bit to minimize shavings, chamfer the hole with a 1/4" bit and reseal it with a pop rivet w/sealant after draining. Don't forget to refill the converter before reinstalling.

Well, I've just found out that Ford did put a drain plug in the torque converter. This makes draining it easy. Thank you FORD!

 

[traveler]

I'm new here, but a regular on the tbird forums. We have always recommended draining the old Mercon fluid completely (TC and tranny) and replacing it with Mercon V. It gets rid of the "shudder" that was common to the 4R70W transmissions. Don't know if that is helpful here or not.

 

[SoNic67]

My 4R70W came with Mercon V (per 2001 user manual).

 

[my98nnj]

The seal leak issue that some attributed to switching to synthetic lubricants when they were first introduced was addressed by the oil company manufactures quite a few years ago. It is no longer an issue, google it and you'll learn why it happened and why it no longer happens.

 

[Happster]

I replaced the radiator and lost a bit of fluid in my 06 Explorer with the 6 speed automatic. I stupidly relied upon the Advanced Auto guy too, and put about 3/4 of a quart (1/4 spilled on the ground, thankfully) of Mercon V in it. It calls for Mercon SP. Now I'm getting bucking at low-to-mid-throttle, that goes away if I punch it. I unplugged the transfer case to make sure it wasn't the AWD tranny module that went bad. Still bucking in 2WD. Could putting that small amount of Mercon V in effect it in this way? Probably worth flushing and refilling it. If so, is the Mercon SP still available? Read a lot of posts that suggest that it was phased out and Mercon LV is a direct replacement. Any thoughts appreciated.

 

[swshawaii]

Motorcraft® MERCON® V Automatic Transmission Fluid (ATF) and Power Steering Fluid

Not for use in applications where MERCON® SP, MERCON® LV, Continuously Variable Chain Type Transmission Fluid, Motorcraft® Premium Automatic Transmission Fluid, FNR5 Automatic Transmission Fluid or Type F Automatic Transmission Fluid is recommended

http://www.fordparts.com/Products/Chemicals-TransmissionFluids.aspx

http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=113912

MERCON ATF IS BEING REPLACED BY MERCON V TSB 06-14-4
ATF AS A SERVICE FLUID. (6/30/06)
http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=134113

 

[Flash]

I would make sense that all new seals available now would be suitable for the later type fluids. But just because it makes sense..

 

[SoNic67]

MerconV is compatible with older seals too, that why the TSB from 2006 recommends it for cars starting with 1980 models.

 

[Happster]

Thanks guys. But I know (now) that V is not compatible with SP. Just hoping for some feedback on whether about 10 oz of the wrong fluid mixed with the other 12 quarts of the right fluid might be causing my problems or might cause other problems. It's not acting like I'd expect a tranny to act if it was slipping. It's bucking at low-to-mid throttle at about 35 MPH, as though I'm skipping a cylinder until I add air by getting on the gas. It's fine off the line. I'm hearing from other blogs that the only risk of running the wrong fluid is ruining the seals and causing leakage. Just hoping some Ford tranny doctor might have a second opinion on that question. I'll put new plugs in for now and hope to hear from someone. Thanks!

 

[Sonne]

Hello All,

Note that Mercon V is the newest version of Mercon fluid which is not a synthetic oil an is backward compatible with previous Mercon versions. Mercon SP and LV are not synthetic either but should not be used if regular Mercon is recommended. The difference between these ATF fluids is the viscosity, additive package and the friction modifiers. You want to use the correct fluid type for the application with proper amount of slip/grip properties and additives the transmission was engineered to have.

In theory should not be any issues with seal compatibility. The only incompatibility between the fluids would be between the additives (they could possibly de-activate each becoming ineffective and settling to the bottom of the pan and converter and plugging up the filter in one possible senario).

The biggest problem with using the wrong fluid is you run the risk of ruining your transmission.

You can get away with completely draining the transmission and converter and refilling. An additional step you can take is an additional drain and refill after taking the truck around the block.

-Sonne

 

[Happster]

Thanks Sonne. Very helpful. I'll do a flush. FYI, I was able to trace the bucking to an ignition issue. Coil was cooked on cylinder 7 and plug was firing weakly and only sporadically. Nice to learn that my truck has the idiotic plug design with the electrode shield carbon build-up that causes the plugs to break off in the head. But I followed the TSB 08-7-6 to the T (OK, engine WAS a little warm and got them all out. Of course, #7 was not firing and the plug shield had no carbon, so that came right out. But thank god the other 7 did! No one in my area had any nickel anti-seize so I'm waiting for a tube off ebay and will take them out and coat the shields later. Nothing's easy!