Gearbox oil

[TK2015]

I am going to change the gearbox oil in my new (to me) 996 Carrera soon. I know that the recommended oil is SAE 75W-90 Mobil (Mobilube PTX) or Shell (Transaxle) - thanks Richard for the superb technical article - but I was wondering if anyone had tried any other brands?

The car has done 91,000 miles and the change to 4th is getting a bit notchy. I am currently using Redine (Red Line?) gearbox oil in my track day E30 M3. There was a noticeable improvement in gearshift quality from cold and a reduction in notchiness when I switched to the Red Line in the BMW but as the 996 is my daily driver I am reluctant to experiment too much and was wondering if anyone had tried the Red Line 75/90ns - which is advertised as "developed for Porsche" on the Porsche Shop site?

Any recommendations very welcome.

 

[Richard_Hamilton]

No experience of Red Line myself, but it comes out reasonably well in this report. See page 19 for results. http://synpsg.com/uploads/g2457_Gear_Lube_Whitepaper.pdf. Unfortunately the Shell product wasn't included in this test. I would say that if you have a positive experience with Red Line, then give it a try as it is obviously a quality product.

I got the link from RennTech and it might be worth searching there, as the Americaans tend to experiment a bit more with alternative products.

 

[TK2015]

Thanks Richard - I'll put a post on there too.

 

[oilman]

Redline oils are all very good, possibly the best available and their gear oils are probably their best products. Well sell loads of Redline and everyone who uses the correct oil reports no problems at all.

Due to the little crunch you are having, I would try either the MT-90 or Lightweight Shockproof

http://www.opieoils.co.uk/c-415-redline-gear-oil-final-drive-oil-atfs-mtfs.aspx

Cheers

Tim

 

[TK2015]

Tim, you would recommend the MT-90 or Lightweight Shockproof over the 75W90NS GL-5?

Out of curiosity, could you tell me the differences between these three grades?

 

[TK2015]

Just to clear up any confusion - because I was confused for sure - I have just spoken with Opie Oils on the phone. It turns out that MT-90 would work but it's a GL-4 oil not GL-5 so not really recommended. Lightweight Shockproof would also work but is really for racing application or where there is serious problem shifting from gear to gear. The 75W90NS GL-5 is the oil that Opie recommend as being correct for the 996 C2 in most instances.

Incidentally, they also said that after 92,000 miles and nearly 10 years, any decent oil should provide a significant improvement in shift quality over the stuff that's currently in the gearbox!