So it's been a few years since this discussion has taken place, and the ZF6 is not as popular or common of a transmission as it used to be.

The Haynes manual calls for Mercon V in the ZF6 manual transmission. The specifications and ratings for automotive fluids are constantly changing. Ford may have recommended Mercon V ATF back in 2002, but in 2017 the fluid has obviously changed a bit.

Personally I think Merc-V ATF is way too thin of a fluid for the ZF6 transmission. In the past few days I flushed my ZF6 with cheap walmart Merc-V and now I'm hunting for an optimal fluid or mixture of fluids for the transmission.

Years ago there was a thread about a board member's 'special blend' of fluids and additives and numerous people had tried the mixture and reported it to work well. I found that thread and most of the oils and additives are no longer available for purchase or hard to find because the labels have changed.

What would you recommend for a ZF6 manual transmission? I'm going to try adding lucas oil stabilizer to my Merc-V fluid today.

 

Anyone? I know that there are some very knowledgeable people lurking around here...

 

I used the Merc V AFT in mine, and it shifts great in all temperatures.

 

I traded my old 03 f250 6.0 zf6 back a year and a half ago because I thought it was fixing to have a lifter failure since I started seeing metal fuzz on the magnetic drain plug.

Anyway I ran Royal purple synchomax or the Pennzoil version I'm not sure of the name of it but both are basically the same as GMs sychromesh fluid or Fords synthetic manual transmission fluid. It was just slightly thicker than the atf and helped quieten down the gear rollover noise mine made with the single mass flywheel. You can't go too thick because it needs to be pumped through the cooler.

I ran those fluids from 50,000 miles til I traded it at 300,000.

 

So we have one vote mercon-V and one vote for royal purple synchromesh.

Any other ideas?

 

Motorcraft mercon V

 

Correct - I suggest that you contact a Ford Dealership for their recommendation based upon your model/year/VIN. That would help to ensure that you have the correct fluid for the application.

 

Okay, anyone else have a recommendation?

I'm going to drain a bit of the ATF from the transmission and top it back up with lucas oil stabilizer.

 

I have been working as a outside contractor at the ZF plant in Marimar FL. The Facility manager is very knowledgeable I will ask him tomorrow. Just hold tight to then. I will try and post what he says during the day.

 

I went with Mobil-1 full synthetic in my 02. I am at 200K with no issues.

 

Another vote for Royal Purple...No rollover noise at all.

 

How about this...Shell Spirax S6 ATF A295. Has anyone used this. It's rated for Allison TES 295 and ZF TE-ML. I have a ZF6 750 in a Ford 6.0 and have been using Schaeffer ALL TRANS in transfer case and transmission.

 

Motocraft MTF as per the manual...

Motorcraft Full Synthetic Manual Transmission Fluid
Part Number: XT-M5-QM
Spec: WSS-M2C200-C

 

What year is you truck and owners manual from. My manual states this in the picture for a manual 6 speed ZF6-750. Says straight Mercon. And is your tranny or where the info is coming from a manual 6 speed? Seems Ford has jumped around quite a bit. Thanks for any help.

 

All in the signature.