Rough shifts caused by wrong fluid?

[Rodger]

2000 S, 39K miles, 6-speed manual.

The shift action when cold (below 60 degrees) is horrible, but improves to an acceptable level once the transmission has warmed up. Despite that, it doesn't shift anywhere as good as my '99 Boxster did with 34K miles. I had a shop verify the fluid was full and the car had the 30K service 11K miles ago. Clutch action is normal, with the engagement in the top 30% of the pedal travel, no slippage. Stock shifter.

Is there perhaps a better fluid I could add for smoother shifts? I've used Redline MTL or Gear oil in previous cars. I miss being able to bang through the gears. I'm careful to baby it until it warms up so as not to make it worse.

:help:

[White987S]

You are not due for a fluid change until 60,000 miles. But, you could do it early. I have heard good things about Red Line and Royal Purple.

[Rodger]

AH, a correction. I guess the fluid wasn't changed at the 30K service, as the receipt didn't list it.

Time for new fluid! Anyone with first-hand experience on alternative fluids?

[mee]

2000 S, 39K miles, 6-speed manual.

The shift action when cold (below 60 degrees) is horrible, but improves to an acceptable level once the transmission has warmed up. Despite that, it doesn't shift anywhere as good as my '99 Boxster did with 34K miles.

Is there perhaps a better fluid I could add for smoother shifts? I've used Redline MTL or Gear oil in previous cars.

The 6-speed is a completely different tranny than the 5-speed and shifts worse. Since you're out of warranty anyway, bag the conventional gear lube that Porsche puts in. Redline synthetic (forget the exact "gear lube", but it's GL5) is an improvement due to better temperature stability. MT90 is better, and MTL better still. MT90 and MTL are for transaxles which is what we have (with synchro friction enhancers), but are GL4. MTL is slightly thinner and gives you more of that "warmed-up" feeling. When MTL is really warmed up, it shifts like a good Japanese tranny.

There is some debate as to whether Porsche requires GL4 or GL5. GL5 offers better load (shear?) protection, but the additives are supposed to be more corrosive on the synchros (brass/soft metals) than GL4. I am more worried about synchro wear due to the crappy shifting and missed/grinding gears than load because I don't take my car to the drag strip every Sunday, and I believe the "S" tranny is used (a derivative) in the 911s which have a lot more power. Even the 5 speed Audi/VW trannies have held up to 3.4L swaps and supercharging. I have never read of someone blowing up their tranny.

For me, synchro life and shifting (which is pretty much a no-go show-stopper with the car) were more important. This info is from memory since I did my S many years ago. YMMV. All regular disclaimers apply. You get what you pay for, etc., ...