The Diesel Stop banner

1 - 4 of 4 Posts

·
Premium Member
Joined
·
4,058 Posts
Discussion Starter #1 (Edited)
My intent for building this spreadsheet was to compare various lubricants for the ZF-6 Manual Transmission and NP-271 and NP-273 Transer Case. (Not the 4R100).

* Disclaimer. I do not make any recommendation on the spreadsheet.*

(I may make future revisions and would appreciate feedback on any data errors I have made.)
 

Attachments

·
Premium Member
Joined
·
4,058 Posts
Discussion Starter #2 (Edited)
If at all possible, I would like this thread to be a discussion of technical and mechanical reasons for various weight (VISCOSITY) lubricants for only the ZF-6 and the NP Transfer Case found in the Ford Superduty. Example: Fluid dynamics of too thin a fluid not providing enough film strength on gears OR too thick a fluid's inability to reach all surface areas requiring lubrication OR that makes shifting notchy or hard in cold temps.

After about 100 hours of reseaching forums, I can say that there is really no wrong answer for the ZF-6, nobody has posted catastrophic failure after adding a specific brand or type lubricant as long as it is an ATF or an MTL.
Ofcourse, gear oils are too thick for consideration.
Besides, an owners experience is going to be dependent on the climate they operate in.
Therefore, there is no universal correct or wrong answer.

But if you have rebuilt a ZF-6 or NP Transfer Case and found the damage was the result of lubrication, that would be very helpful.
Thanks
 

·
Super Moderator
Joined
·
25,753 Posts
But if you have rebuilt a ZF-6 or NP Transfer Case and found the damage was the result of lubrication, that would be very helpful.
Don't have that, but do have an example of the result of LACK of lubrication. Had a loose line empty the tranny and it locked up. 😕

Good research.(y)
t would be handier if you attached an excel spreadsheet, so the headers could be locked.
 

·
Premium Member
Joined
·
4,058 Posts
Discussion Starter #4
The original Ford Owners Manual called for MERCON in the ZF-6, that was discontinued and replaced by MERCON-V which has also been discontinued and replaced by MERCON-LV.
The original MERCON was a Mineral based ATF and was reputed to sheer down in the 4R100 to a viscosity similar to what the MERCON-LV is new in the bottle. I was not able to find a UOA for the MERCON from a ZF-6. The MERCON-LV is full synthetic (yes, there are opinions on the definition) and sheer stable.

I first became interested in the choice of ATF fluid when I flushed my Power Steering. I opted for Valvoline Max-Life and it made my pump whine immediately. A sound similar to when you turn the steering wheel to the full stops. I replaced it with Mobil-1 and the sound disappeared immediately. They are both full synthetic.

These two non-Motorcraft ATF (Mobil-1 ATF and the Valvoline Max-Life ATF) are the more popular replacement fluids for the ZF-6.
If you look at the chart in Post #1, you will see the Mobil-1 has a similar viscosity as the MERCON-V which are both thicker viscosity than the Valvoline Max-Life. Is it the lighter viscosity that adversely affects the Power Steering pump?

As I researched further, I found we have more choices than ATF. There are also MTL/MTF and fluids designed for Synchros and which are safe for "Yellow Metals" found in the Synchros of the ZF-6. The MTL/MTF is a slightly heavier viscosity than the ATF range and an actual gear oil with superior properties for gears such as Extreme Pressure and Anti-Wear. For those who tow heavy, this might be an advantage to consider.

Next is discussion of the Transfer Case. The TC is chain driven.
 
1 - 4 of 4 Posts
Top