What kind of oil?

Use a quality 75/90 weight. Some of us add a NAPA bottle of limited slip additive, too, assuming some of the clutches are still trying to do their job.

Change every year, and after a track event.

Larry

What do you think of Lucas 80/90 ?


http://www.lucasoil.com/products/display_products.sd?iid=43&catid=4&loc=show

Dittos on the 75/90. I have always had good luck with Redline and Castrol for gear oil. Don't know about synthetic for this use though...

Synthetic works in the ZF posatively wonderfully.

I run Synthetic in mine too. Is it really needed, who knows.

But it does the trick.

There was a discussion before about using synthetics might cause an oil leak.I don't know but use 80/90 regular oil just in case.

quote:

Originally posted by jwr2968:
There was a discussion before about using synthetics might cause an oil leak.I don't know but use 80/90 regular oil just in case.

That's ridiculous. Run Mobil1 like the race cars do. Whatever natural is synthetic is better.
It will never breakdown, never gum up. It sticks better to the internal components during disuse, therefore when you fire it up, there is less metal to metal contact.
Every whichway you turn, it is just better.

I've been using synthetic in my ZF for years without problem or leaks.

I also used synthetic Mobil 20/50 in my engine, but as Coz will recall, I experienced a lot of blow by. Clean oil was spattered in tiny dots on the rear face above the exhausts after every long run. We all thought it was the turkey tray, but as it turned out, changing to Castrol 20/50 non synthetic solved the problem. Go figure. Guess the engine is still too new.

So what's best for the ZF - if money doesn;t matter (in this case) do I stay with synthetic or not?

If your already running synthetic Deeb and not leaking, leave well enough alone and keep running it. It sure can't hurt. The way I see it, the more protection the better with the ZF.

Lloyd in the past has said that a better quality non synthetic oil is just fine. Just needs to be changed yearly and or after racing it.

I have seen situations that switching to synthetic after running non synthetic will cause leaks to start, usually around the back cover plate area and sometimes from the side cover plates.

And vice versa where switching to non synthetic after running synthetic has stopped leaks.

6 of one and 1/2 dozen of the other.
I look at it this way, if it works, don't fix it. Something else will break soon enough to keep you busy.

But hey, what do I know. I'm sure there are others here that know better than I.

quote:

So what's best for the ZF - if money doesn;t matter (in this case) do I stay with synthetic or not?

I've used Mobil 1 synthetic and it causes leaks so I switched back to Castrol. Synthetic seems to be alot smoother shifting, is there an additive I can use to make the shifting smoother with Castrol?

I've had a bad experience with synthetics. I just got through rebuilding my rear axle in my truck. Ford fills all its rears with synthetic 75/125. When the axle started making noise(80,000), I changed the fluid and the fluid that came out looked like mud water. I drive this truck everyday, so 20,000 later, looked the same again and all the bearings looked like they had been run in water. From what I hear the synthetics absorb more water than the dino fluids do. Just my one experience with synthetics, so I call synthetics bad.

It's just the opposite with water. It's one of the reasons it's better.

I understand your feelings but there may have been something else happening there. The biggest problem with synthetic is that it is too slippery.

Things that need friction to work like limited slip clutches and transmission syncros don't work as well with it.

As far as leaks go, try adding a teaspoon of brake fluid. It will swell the seals and o-rings, hopefully enough to stop the leaks.

There are a lot more brands on the market now. I like Mobil1 also. I've been using it in everything for about 20 years now.