[DeTomaso] ZF Gear Lube Question

[JDeRyke at aol.com]

In a message dated 5/28/10 12:21:49 PM, joernco at online.no writes:

> What is the amount of GL4 oil in a ZF?
> -Only drained =      Pure guess- maybe 2-1/2 quarts since even inverting 
> the gearbox doesn't drain                          all the lube
> -Rebuilt =                3.5 liters/3.67 quarts if bone-dry
> 
As to the type, remember the ZF transaxle as a complex and expensive car 
part PREDATES the 'GL' lubrication rating system. Not sure what GL rating 
parameters are and I suspect no one else on this list has found out, either. All 
the ZF factory manual says is to only use 'mild' EP (extreme pressure) gear 
oil, 80W conforming to spec- Mil-L-2105 (A). In the '60s, 'mild' meant 
low-sulfur gear oil. They also say its much more important to keep the level up 
to within 10mm of the fill plug lip rather than use too little of any 
particular type lube.

I use a posi-lube additive in our '72's lube since it was made for 
clutch-type limited slips like the ZF. I once asked LLoyd Butfoy this question in 
public at a Tech Session in 'Vegas. He said, 'Posi-lube won't hurt, and in 
some assemblies it may help'. A tight clutch-type posi (any brand) may chatter 
at low speeds in sharp turns but almost all our vintage 35-40 year old posi 
clutches are badly worn. If in pouring rain or on other slippery roads you 
turn sharply and feel a jerking from back there, that's the posi clutches in 
the differential catching and releasing as they do their job; a posi 
additive will help such a ZF to work more smoothly. FWIW- J DeRyke