Synthetic Gear Oil / 901 Tranny

[copper]

In a previous thread re gear oil, there were numerous comments about not using synthetic gear oils in manual transmissions, or adding a molykote(sp?) to it.

Liqui Moly is a German company that has been making lubricants for racing since 1956. They have Lubro Moly which is a fully synthetic motor oil, and as well, they have their synthetic 75W90 gear oil, which they recommend for Manual Transmissions.

I would love to use Swepco 201, but being in Canada, the costs are way up there when I add the product, shipping, UPE brokerage fee, duty and taxes.

I can get the Liqui Moly products locally and our local P-mechanic uses it on all transmissions.

The link is here
http://www.hopefungautoparts.com/Gear_oil.jpg

and all of their products
http://www.hopefungautoparts.com/LubroMoly.htm

Comments please...
Also, what do the 75 and 90 mean in the numbers, as opposed to 80W90...

Jim

[KobaltBlau]

First of all, I don't know anything about liqui moly gear oil, and I couldn't find very much information on it.

This is copper's original thread on the topic:

901 Tranny gear oil

here's another recent relevant thread:

Redline Oils

copper, did you do the test to see if you have a limited slip differential (from the first thread)?

I would guess that you do not, which makes things pretty easy. The main thing is that if you want to use a synthetic you should use one without "friction modifier", which is the same thing as "limited slip additive". If you can get Red Line 75w-90ns that would work nicely.

However, you did not quote very low temperatures in the other thread, so non-synthetic base oil should be fine. As I mentioned in the second link above, Chevron Texaco Delo 80w-90 GL-5 would work really well, and should be easy to find and inexpensive, but it is very high quality stuff. I think this is the easiest and lowest cost solution, without sacrificing any quality.

If you do in fact have a limited slip, things are a little bit more complicated ... let us know.

[copper]

Thanks again KB. You always come through.

Haven't had her on the hoist yet. She's parked until I get all the parts I need to do the clutch, valves and all seals and gaskets.

Should be in the next couple weeks.

Lubro Moly specifies that their lube if for manual transmissions. Again, our local Pcar mech. uses it religiously on 901s and 915s.

I'll check her on the hoist.

But if it's german, it can't be bad...

Jim

[copper]

And if it makes a difference, Lubro Moly sells a friction additive seperately from their synthetic oils and gear lubes. This I would imagine would indicate that their procducts don't have it, so they can be used for either case, with the friction additive if needed.
The friction additive is here;

http://www.hopefungautoparts.com/gear.jpg

Jim

[copper]

Given that I've had to wait for the parts, my last runs for the year to the mechanic and back will be around the 5 degree mark (42F) or a little less. Not sure if this makes a difference.

Jim

[KobaltBlau]

Those temps are still just fine for non-synthetic 80w-90.

The friction additive that you reference is not the same as the friction modifier that I am talking about. The one you reference is an antiwear additive for gears, with lots of moly in it. I imagine it is similar to the Dow Corning Molykote M.

The friction modifier I am talking about is specifically made to keep multiplate clutches happy; Here is an example:

ford racing friction modifier

I don't believe that pelican sells this type of product but it is available at lots of local auto parts stores, it is not hard to find. the Red Line tech told me it doesn't matter much which brand you use, but not to exceed 1/2% in a 901 or 915.

You _only_ need to add this if you have a multiplate clutch limited slip like the factory one and exprience limited slip chatter, which usually manifests itself as a slight vibration at low speed, for example pulling away from a stop sign and turning fairly tight. this chatter doesn't really hurt anything but can be a nuisance. If you don't have a limited slip there should be no reason to add any friction modifier.

It would be good to check first if you have a limited slip, but if you do have one or can't check, I would start with Red Line 75w-90ns or the Delo I mentioned above and add friction modifier only if you find out you have a limited slip and experience chatter.

With your temperatures the Delo should be just fine, and it is a very high quality non-synthetic oil that would cost less than the Red Line. Both are very good, though.

The lubro moly may be very good as well but your local mechanic is the first person I've heard of using it, so it's hard to say. I can't conclude that the product is made without friction modifier added without more information, which I believe is the key thing for porsche synchronizers in synthetic oil.