Reply to "What oil to run in my ZF gearbox?"

George,

It seems that new Pantera owners (and some of us long-time owners) are looking for specific gear lube recommendations, as opposed to reading debates on whether to use GL-4 vs. GL-5 and to a lesser degree synthetic vs. mineral based gear lube. As far as the synthetic vs. mineral based oils are concerned, Lloyd Butfoy says synthetic based oils are fine to use but the ZF might leak a bit when using them. Lloyd told me, even brand new or freshly rebuilt RBT's (ZF's) can leak a bit when using synthetic oil. In these cases, some will stop leaking after a period of time, when the gaskets "swell up". The only real benefit to synthetic oil, in a street driven Pantera, is the ZF may shift a bit better.

Oddly enough, the specs in our owner's manual calls for GL-5; however, I have always believed that to be a misprint or a typo. I'll take RBT's recommendation over DeTomaso's without hesitation!

As mentioned in previous postings, it's vital that the oil is changed in a ZF once per year. The reason for this is, condensation tends to form inside the ZF's case.

Here are a few gear oil recommendations. All of these oils are safe to use in our transaxles:

Redline MT-90. This is a synthetic, GL-4 gear oil, 75W90.

Redline 75W90-NS. This is a synthetic GL-5 gear oil but without the friction modifiers for hypoid gears, common to GL-5 gear oils.

Brad Penn (formerly Kendall) Classic. This gear oil is a mineral based GL-4, 80W90.

I hope this helps.