dhsieh

My manual 08's Carrera S has 24k miles and I want to service the gearbox oil. The local Porsche dealer quoted me an outrageous price. The other 2 independent Porsche specialty shops quoted me much more reasonable prices around $140. However, one uses Redline while the other uses Liqui Moly (both ar full synthetic). I wonder if there is any difference between these 2 brands at all?

No HTwo O

Buy 3 quarts of OEM fluid from Sunset, and bring to the prefered indy shop. Shop time is about an hour. Sunset charges about $26/quart, IIRC.

chago996

Why change gear oil so early? It last much longer than engine oil due to no combustion contaminants, change in acidity, etc. I would follow the recommended cycle and use factory fill. Not what u wanted to hear perhaps.

No HTwo O

I changed mine early (5 years at about 45,000 miles). Here is the UOA report from Blackstone:

dhsieh

I had a 01' 996 manual and at 60k miles when I changed the gear oil, the mechanic found some small debris while draining the old gear oil, a lesson I learned that it never hurts to be diligent than sorry. So my 08' Carrera S is now alomst 4 years with 24k miles, i thought I'll be more deligent than my prior 01' 996...

Macster

It is very common to find metal debris, sometimes rather large pieces too, in the tranny fluid.

Almost all of the time this is normal.

My advice is if you want to change the fluid, just take it to the dealer. While mine charged me around $45/liter (approx. 3 liters) for the fluid the labor was only 0.3 hours, for my 02 Boxster 5-speed.

I think I paid less than $250 for the service. Got to chat with the techs too while the car was being serviced.

Given you'll probably change the fluid just this once while you own the car, why bother shopping around for some deal and experimenting with some other fluid?

Sincerely,

Macster.

dhsieh

Well, first of all I am too sure about the metal debris normal part. I have owned many cars in the past, mostly German & Japanese imports. I changed tranny fluid around every 30k miles and has never seen metal debris from the drain. For some cars, the drain plugs were magnetized and thus they did collect fined powder-like debris on them and I would call that normal. I understand that some Porsche owners drive hard and thus put more strain on the tranny. But, I don't take my Porsche to track and only drive aggressively occasionally. As a result, having metal piece debris coming out of drain is not something I call normal.

Nonetheless, I think your advice on sticking with OEM fluid is helpful. The reason I choose independent shops is because they'll give you much better personal service and sometimes provide information that dealer won't tell you.

alexb76

So, by saying Clutch oil, do you mean Transmission oil?

If so, it's a mystery what's best oil. I like to change mine too, but it looks like some aftermarket oil doesn't work very well on our cars, and yet, OEM fluid doesn't work very well on track. So, if you do NOT track, I definitely recommend to just get the OEM and have someone change it.

If you track, then do some more search and if you found a good oil, let me know too!

dhsieh

From another forum thread (http://www.6speedonline.com/forums/9...ip-manual.html), one post said that "on manual cars use delvac 75w90! this is factory fill in the 997 gt3rs and can handle high temps". I wonder if there is any truth to it? From Amazon, Mobile 1 Delvac is sold around $11/quart. My local Porsche dealer asks OEM $45/Liter bottle & $350 for service (Sunset Porsche quoted me $25/Liter but needs add shipping).

dhsieh

From the same 6speedoneline thread above, another posted:

If you track the car change it once a year, at a minimum. If you don't track it change it every 2 to 3 years, regardless of mileage.
__________________
Matt Monson
Guard Transmission LLC
303-530-1094

Looks like this person is a Porsche transmission specialist. Based on my prior 01' 996 experience, he is right on the money. If some Porsche authority can confirm Mobile 1 delvac 75W90 is the right substitute for OEM oil, the job can be done no more expensive (< $90) than other cars in my opinion. This is the safest and least inexpensive preventive maintenance any Porsche owner should seriously consider.

What Porsche recommends of 90k miles change interval is just totally ridiculous. This reminds me of my Bimmer where BMW, because of it free in-warranty regular service, claims life-time fill auto tranny fluid, radiator coolant and 15k miles engine oil change interval. What's wrong with these German manufacturers?

No HTwo O

Don't use Mobil Delvac 75W90 in a modern Porsche trans.

I use the Delvac in my 993 Turbo and it's great. This was the "factory fill" back in 1997.

I have UOA's on both (Delvac and 987/997 OEM fill) and they are very different.

dhsieh

Ok, looks like the safest approach is to order OEM oil from Sunset Porsche and have my local Porsche shop to service it. According to the user manual, it prints "Manual transmission and differential approx. 3.1 quarts / 2.9 liters transmission oil". I suppose 3 liter bottle should do it.

alexb76

If you don't track, that's absolutely the best oil bar none!

utkinpol

In my car I have now mobil 75w90. It feels a bit heavier while gearbox is cold.

Macster

There are always exceptions, cars that upon a manual transmission fluid drain will not have any metal in the oil (because there isn't any or simply because it just happened to be too far away from the drain hole and wasn't caught up on the fluid's flow out the drain hole) but metal debris in the drain fluid, especially the first drain, is common.

Unless the tranny was misbehaving prior to the drain (sometimes this prompts a fluid change in the hopes the new fluid will resurrect the transmission) some debris is nothing to get that excited about.

'course, it depends upon what the debris looks like. Some indistinct grains or a small chips which is machining swarf: No biggie. A teaspoon or more of fine metal swarf (run a magnet through the oil) which is wear swarf: A biggie. Maybe.

Regardless, an early transmission/diff fluid change is not a bad idea and some knowledgeable people (Mike Miller who writes for Bimmer) highly recommend.

The Porsche techs I talk to suggest that if one wants to modify say the tranny fluid drain interval to cut the factory drain interval by one third to one half. Thus a 90K miles drain interval becomes a 60K miles or even a 45K miles drain interval.

They do however point out that Porsche specifies say a 90K miles fluid drain interval because Porsche's testing has confirmed the fluid will hold up quite well over this span of miles, given reasonable use of course.

Sincerely,

Macster.