Which transmission fluid do I use??

[Robert Nicholson]

The owners manual calls out for Motorcraft mercon for the 5spd manual that is in it. I can’t find straight mercon anywhere! What oil is safe to use in my transmission? It’s got 183k on it and I don’t know if the fluid was ever changed. Just want the transmission to last as long as Possible. Thanks!!

 

[rusty ol ranger]

Mercon V or whatever number they are up to now is fine

 

[sgtsandman]

There has been some discussion on this recently. Apparently Dex/Merc is a suitable sub and works fine in the older transmissions.

 

[Robert Nicholson]

Mercon V or whatever number they are up to now is fine

Are you sure? I just saw another thread where someone said definitely not to use mercon v in a manual?

 

[sgtsandman]

Are you sure? I just saw another thread where someone said definitely not to use mercon v in a manual?

The official Ford answer is to use Mercon V. It will be interesting to see what their answer is when Mercon V is no longer made. Mercon LV and Mercon ULV are not backwards compatible according to Ford.

I’ve tried the Castrol version and found it wanting after about a year of use. Shifting into 1st was stiff and the transmission had to be aligned “just right” to get it into reverse. I’ve never had that problem with the real stuff.

 

[Shran]

Dex/Merc II/III. Doubt you will see the end of production for that fluid anytime soon - you can still get Type F, that's much older.

 

[4x4junkie]

×3, Dex/Merc.

Ford quit producing regular Mercon fluid many years ago and at the same time also yanked the license for aftermarket companies to be able to use the name "Mercon" (apparently in cahoots with GM yanking "Dexron III").
"Dex/Merc" is the new name Valvoline, Castrol, and others came up with to (try to) be the least confusing as possible (previously the fluids were labeled "Dexron-III / Mercon"). It is the same fluid.

The official Ford answer is to use Mercon V. It will be interesting to see what their answer is when Mercon V is no longer made. Mercon LV and Mercon ULV are not backwards compatible according to Ford.

Ford once said that about Mercon V and Mercon too... They should've stuck with that advice since it's actually true (at least with manuals).

 

[DILLARD000]

For MerconV compatible ATF, personal preference in the order listed:
* RedLine# HiTemp\30205
* AmsOil# SSMV\atf1g
* ValvoLine# SGMV\887972 (commonly available in big box stores)
Read label fine print on whatever ATF you're considering
for compliance to specific Ford standard for MerconV.

 

[00t444e]

Regualr Mercon is easy to find but that's not what works best in the 5 speed. Use Pennzoil or Valvoline Syncromesh.