Reply to "zf gearbox fluid/oil"

In my 15 years of ownership I've seen this discussed many, many times. A few years ago I had Lloyd go through my ZF while changing to a higher fifth gear ratio.

I utilized our face to face time with a probing discussion about lubricant for a Pantera ZF. What I took away from the discussion was it really makes no difference what quality, properly-rated oil you use.

AND...

You will be changing the oil regularly every year.

Condensation within the ZF due to minimal usage and failure to fully warm the ZF oil on long drives to burn off such condensation, is the main issue to oil maintenance.

In a nutshell choose any oil that suits your fancy and then change it all out 12 months later and your ZF will not exhibit any oil related issues.

To answer the question you posed regarding mixing the trapped oil with a new or different oil the issue is a non-issue. Mixing the trapped oil with a synthetic oil has no ill affects.

One issue you've probably noticed in your readings is the ZF needs to have some miles put on it to fully distribute the oil after which you should recheck at the fill plug for proper final oil level.

If you're happy with the performance of the oil you choose this time around then you can just repeat that same brand, or try something new to see if it offers better performance for your needs.

Again, you're going to be changing it every year anyhow, right?

Larry