The new Mercron Vs are suposed to be a suplement for dexron III Mercron, so there shouldn't be any reason you shouldn't use it.

 

When I did my 04 I went to the ford garage to get some mercon ATF and talked to the service manager he told me to use only mercon in the transfer case not mercon V and they are not interchangeable and they do not mix.

 

The back of my Castrol Mercon V ATF bottle says "Certified and approved by Ford for all cars and trucks that require Mercon or Mercon V..."

 

Uh oh. Thats not good.

 

Ya I am not a mechanic but I do know in the book it says mercon V does not mix with anything and my owners manual is very specific the transfer case use mercon ATF????

 

I am not a mechanic either but for what its worth... I dont know.


https://www.ford-trucks.com/tsb/full...hp?tsb=06-14-4

" This article supersedes TSB 01-15-7 to update the vehicle application chart.
ISSUE:

MERCON® Automatic Transmission Fluid is being replaced by MERCON® V as a service fluid.

ACTION:

Beginning immediately all automatic transmission / transaxle applications requiring MERCON® can now be serviced using MERCON® V or MERCON® Automatic Transmission Fluid or dual usage fluids labeled MERCON® / MERCON® V. After July 1, 2007, MERCON® Automatic Transmission Fluid will no longer be manufactured, therefore, availability of this fluid will only continue for however long it takes to deplete what remains in inventory. "


http://www.imakenews.com/lng/e_article000564317.cfm?x=b11,0,w

" Ved, based at Ford’s Automatic Transmission New Product Center in Livonia, Mich., is the company’s lead development engineer for ATF. He noted that although his company has recommended Mercon V for all vehicles for the past seven or eight years, most Ford models on the road continue to be serviced by Mercon. Mercon V, however, is a far better product that more closely resembles the factory-fill ATF which Ford has used for over eight years. It requires the use of a more shear-stable viscosity index improver, and Group II or Group II-plus base oil to meet its viscosity and oxidation targets.

“All transmissions recommending Mercon ATF can now be serviced with Mercon V,” Ved later told Lube Report. “Mercon V is a tighter specification, requiring better anti-oxidation, antiwear and anti-shudder properties from service-fill ATFs. We are doing this because we want to ensure our customers get the better fluid. "


MBB how long you had the Mercon V in yours?

 

A couple of weeks ago I was having the OD/3/2 downshift clunk so I decided to lube the yoke. While under the truck I figured I would check the Tcase fluid. Well, surprise, suprise, I took a bath. The truck was on level ground and it was about 1 1/2 qts. overfilled, and also quite dirty. When it warms up again I'll change it. BTW, lubing the slip yoke didn't help. I also noticed that when I pulled the Dshaft that the fluid that came out the tail (a small amount) smelled like 80/90. It definitly was not ATF.?? Any other ideas. (04 4.6L 4R70 65,000mi.) Thanks.

 

Uh oh, if your tcase is overfilled, it means the seal between the tranny and tcase is leaking, right?

 

mjspanky, something sounds off/wrong.


I haven't pull this t case, but if it's like all the others, there isn't a way for the tranny fluid to flow into the t case=bad seal or not.

 

I don't think there is any "cross" leak as my trans fluid has never been low. It's almost like they laid it on its back and filled it, put the plug in and put it in the truck. Oh well, the clunk is more of a concern because it doesn't do it if I switch off OD.

 

I noticed today that the tranny fluid dipstick says "Use only Mercon V". Just food for thought.

 

The Transmission takes only Mercron V.
The transfer case calls for regular Mecron, but like previously posted Mercron V is a possible substitue.








black04lariat, I changed my fluid about 10K miles ago with the mobil 1 mercron V
I would eventually like to change the axle fluids to full synthetic and possibly the tranny fluid to the same mobil 1 mercron V. Hopefully for the better of the drivetrain, and possibly better mileage b/c of the less friction(talking a couple 1/10s, but it could add up). I've seen where putting synthetic fluid in all the drivetrain made about a 6 hp difference and 11 ft/lb difference on a rear wheel dyno.