Cold gear change - choice of oil?

Mark_944S2 · 02-05-2003, 10:15 AM

On cold mornings I have trouble shifting from first to second, it is almost impossible to do without a slight crunch.

As soon as the car is warmed up for a few miles all is fine.

Has anyone any experience of the best gearbox oil to use? I have heard swepco recommended by some and others said it made cold shifting worse! Also there is mobil 1 75W/90 which some recommend.

Porsche recommend 75W/90 - has anyone tried 70w/80?

Thanks

Mark

Makis · 02-05-2003, 01:36 PM

Common problem with S2. Apparently using a 75W/90 synthetic gear lube will sort things out nicely. Worth the try it will not make things worse.

AaronM · 02-05-2003, 01:47 PM

I like Redline 75W90 NS (only use the "NS" variant if you do _not_ have a limited slip differential, use the normal 75W90 if you have the LSD). I just got my 924S so I'm not sure how well it does in the 944/924S tranny but it works nicely in my 914. A good work-around is just to learn how to double-clutch.

Aaron

Mark_944S2 · 02-05-2003, 02:13 PM

Thanks for the info guys, I already thought 75W/90 synthetic was the way I'm headed so it's good to hear about some positive results.

Mark_944S2 · 02-05-2003, 02:45 PM

How can I be sure I don't have a limited slip diff?

Mark

AaronM · 09:10 PM

Quote:

Originally posted by Mark_944S2
How can I be sure I don't have a limited slip diff?

Mark

You can have a dealer check the option codes, or you can find a list of the option codes and check them against the sticker in your owner's manual. If you were in the midwest like me, I'd just say to take it out in snow and see if you get stuck from having only one wheel with traction. That's not a real practical test in California though.

Aaron

EDIT: The oil for a Limited Slip Differential will work fine in a non-limited slip setup, the syncroes will be a little less effective because of the friction modifiers, but no big deal. The oil that's for non-limited slip setups lacks the friction modifiers necessary for an LSD and use of it with an LSD can ruin the LSD's clutches.

Razor944 · 02-05-2003, 09:32 PM

[QUOTE]Originally posted by AaronM
[B]If you were in the midwest like me, I'd just say to take it out in snow and see if you get stuck from having only one wheel with traction. That's not a real practical test in California though.

They may not have snow but they have plenty of sand. take it to the beach, the chicks will dig it.

Roastin944 · 02-05-2003, 10:09 PM

Why is there 80/90 W, and then when you go to 85 it is 85/140. Why is it 140. Is this grade not recommended? I heard that this thickness makes shifting very nice. So for cold weather, you want a lower first number like the 75/90. Is the thicker stuff better for warm weather? Because it is very hard to shift before it warms up, it almost grinds going into every gear, then its decent once it warms up, whats the recommendation?

John

Mark_944S2 · 02-06-2003, 12:26 AM

The little specification book that came with the car lists the following oils for the gearbox :

75W90 GL5
80 grade GL4

So is there any reason I shouldn't try Redline 75W/80 GL5 grade? Is this likely to cause any damage? Most people seem to be going for 75W/90 grade.

As a guideline the 75W/80 grade has 2/3 the viscosity of 75W/90 at 100 degrees C and half at 40 degrees C.

mark

Mark_944S2 · 02-06-2003, 09:34 AM

So one more dumb question :

Can anyone save me grovelling around under the back of the 944 this lunchtime and tell me how big the drain plug key should be?

Thanks!

Mark

AaronM · 02-06-2003, 04:50 PM

Quote:

Originally posted by Roastin944
Why is there 80/90 W, and then when you go to 85 it is 85/140. Why is it 140. Is this grade not recommended? I heard that this thickness makes shifting very nice. So for cold weather, you want a lower first number like the 75/90. Is the thicker stuff better for warm weather? Because it is very hard to shift before it warms up, it almost grinds going into every gear, then its decent once it warms up, whats the recommendation?

John

When the oil gets warm, the viscosity decreases regardless of the weight. I would NOT recommend anything thicker than 90 weight unless you were getting insanely high gearbox temps for some reason. (The 140 weight gear lube is mainly for trucks and heavy-duty transmissions like in racing/hauling.)

Aaron

Roger Hall · 02-06-2003, 04:50 PM

Drain plug is a 17mm hex. I used Swepco and the stuff is amazing.