996 TT manual gearbox oil grade

[maxpaul]

I know the recomended oil is Mobilube PTX 75-90 but is there any alternative that gives a better performance?
My car has done 42K and has been mapped to 500bhp.

[BIG GT2]

i used to run this gearbox in my old gt2 racecar, to high geared but very strong. we used a 75/90 that 76 racing lubricants sell called sunoco gl 5 superlube. it stands up very well to heat and hours of abuse on track. dont know about any other oils for non road use anyway,but this stuff is great, i use it in my old gts race car as well. its 60 quid for 20 litres so you get a few fills of it

hope this helps

[Homer J]

What's the reccomended oil change intervals on a Turbo?

I'm thinking of having mine done, and the front diff as well. I've read up on Sixspeed and a couple of other U.S sites, there's guys on there changing the oil annually.

Mines done just over 60k miles, i'm thinking now would be a pretty good time.

[EvoSlayer]

I changed mine to Redline synthetic gear oil, 75W-90NS, when I put the short shifter and 997 transmission mount in. Car is modified and had probably done around 35k at the time.

[maxpaul]

Thanks for all the information but I need to buy some oil today for a repair tomorrow anyone know a stockest in Hampshire dont want to buy 20 ltr just 3x1ltr bottles

[Rockster]

Homer J said:

What's the reccomended oil change intervals on a Turbo?

I'm thinking of having mine done, and the front diff as well. I've read up on Sixspeed and a couple of other U.S sites, there's guys on there changing the oil annually.

Mines done just over 60k miles, i'm thinking now would be a pretty good time.

IIRC the recommended change interval is 90K miles. My tech buddies tell me the transmission/diffs are robust but I had my 03 Turbo's tranny/diff fluid changed at under 40K miles. Glad I did because in prepping for this job, removing panels to get at the tranny, he spotted a leaking seal around a selector shaft. I got a new transmission covered by the CPO warranty.

Just recently I had the tranny/diff fluid changed in this replacement tranny at around 90K miles so this means the replacement tranny/diff fluid had around 50K miles on it.

The techs tell me that if one wants to be a bit anal about tranny/diff fluid changes to cut the factory recommended fluid change interval from say 90K miles to 60K miles, 50K miles or even 45K miles.

The only way I'd change the fluid annually is if I tracked the car. A lot.

Sincerely,

Rockster.

[maxpaul]

All sorted now Shell Helix recing fluid 75w 90 Mail order from Deamon Tweaks next day. Transmission out for clutch replacement. It now cant handle the 500bhp remap so sachs competition unit being fitted today together with slave cylinder and accumulator.
Thought it would be a good time to change the oil.

[Rockster]

maxpaul said:

All sorted now Shell Helix recing fluid 75w 90 Mail order from Deamon Tweaks next day. Transmission out for clutch replacement. It now cant handle the 500bhp remap so sachs competition unit being fitted today together with slave cylinder and accumulator.
Thought it would be a good time to change the oil.

Not to put too fine a point on it but with the selection of Shell Helix you have stepped off the reservation regarding Porsche approved tranny/diff fluids.

The problem is the Helix fluid may be incompatible with the transmission and its lubrication needs.

However, given that the engine has been tweaked to up its HP output there is no guarantee the Porsche approved fluids would have sufficed.

But with that much extra HP flowing through the transmission it may not matter that much.

The transmission because it has sufficient margin it can tolerate the higher output of the engine and because the Shell Helix transmission fluid does all the right things (and does none of the bad things) the transmission may be just fine.

Or the transmission doesn't have sufficient margin in which case the fluid choice may not matter that much.

No fluid is going to make an input shaft stronger, tougher.

BTW, remember the front diff can receive up to to 40% of the engine's torque so the front diff can receive more torque than its design was intended to handle.

If you believe Shell Helix will help the tranny/rear diff survive this added torque load you have to believe it can only help the front diff.

So, you might consider treating the front diff to a filling of Shell Helix fluid as well.

Sincerely,

Rockster.