alexb76

Yeah, I think I need to be more precise and relaxed next track day (in 6mos) . However, I still think tranny needs some inspection as this was mostly happening recently and not last year.

avader906

Cup shifter cables are thicker - when ordering make sure to order complete kit including non-plastic ends. Will increase transmission noise to audible levels but you will feel every gear change in a bolt rifle kinda way. Search the forum - there are few posts with part numbers. Engine mounts upgrade to solid or semi-solid is recommended and is as easy job to do - helps a lot.

ps: if you track the car, transmission fluid change is recommended at least once a year and is pretty simple really.

GTgears

For a street car that is driven hard, 15k mi. is the maximum I recommend on the oil. When you add in track days, I usually log them as 2500 mi per event. Obviously, with that math, if you do 5-6 track days a year, you are changing your oil at least once a year, if not twice.

The 997 Aisin gearbox in the Carrera is a bit of a problem child. People frequently report shifting problems in 2nd gear even in street cars. I'm talking about shifting problems both on the upshift and the downshift, which are synchro related. These are not to be confused with your specific issues which I think the others here are helping you to sort out and address.

And these weak synchros are where the question of a compromise comes in. The OEM fill on the 997 Carrera has friction modifiers in it that help to make those synchros a little more slippery and mask their weakness. The problem there is that when you track the car and get it nice and hot they are too slippery and you get crunchy shifting.

So what does the track junkie do? He puts in Mobil Delvac. Now, the problem becomes when he's not at the track. On a cold morning, which doesn't even have to be Vancouver in Winter cold, it can be a 50 degree Spring day, with the Delvac in there 2nd gear in particular is going to be an "angry" gear and require you to shift really slowly until you warm it up. If you're just running to the grocery and back before coverage of the F1 race comes on, you might not even get it up to temp. It takes about 20 minutes to get the box up to temp. Many short trips around town won't do that for you. So, you have to ask yourself if that's a compromise you are willing to suffer?

Regardless of wether you go with the factory oil or Delvac, it's time to change it...

996FLT6

To OP- which car we are talking about with respect to shifting issues in 2nd? Cupcables will not work on your c4s. Try a different gear oil like Mobil Delvac before trying engine mounts etc. I always had issue with the 2-3 shift under load. Was running redline gear oil then switched to mobil Delvac - made a vast improvement in ease doing 2-3. Mike

alexb76

Thanks for your help. BTW, Car's a 2007 C4S (NOT GT3), reason I posted here is that GT3 guys track more and might have more experience with transmission issue.

Now, I basically use my car daily, albeit very low milage as I walk to work... and I track 3-5 times a year and have had 6-7 track days since I've had the car in 2009.

It sure does sound like I must change the fluid, as the problems I described definitely worsen the hotter it gets (less issues on 1st session, much more in 3rd/4th session). Having said that, IF Delvac is gonna cause problems on daily drives, it probably not going to be ideal... would changing back to stock fluid help? or I'd really have to upgrade?

Anyone with Delvac on daily cars? any issues with cold starts?

Thnx

Luxter

+1 on this issue.
Got my fluid replaced in 997.1 about 1Tkm ago. A bit notchy 2nd gear, mostly up-shifting (but I always heel and toe on downshift, even in town) and improving with kms (fluid eventually shearing a bit??). It's a matter of taste and careful shifting. Tranny runs very smooth and quiet though.
Just allow your car to warm up properly and she's all fine again.

AYHSMB

There's no magic fluid unfortunately. The OEM fill is sort of a compromise that favors daily driving and becomes too thin under hot track use. A thicker track oil like Delvac will be annoyingly thick for cold day street use.

If you're willing to swap out to track fluids for each track session, or just change for the summer/winter seasons that might help.

I've been curious to try Motul Gear 300 which has a more constant viscosity (less temperature variation) than other oils, but that's dangerous untested ground.

Luxter

I am curious too. It is available in Calgary at somewhat premium $$$. Motul looks good on spec sheet, last I heard however is that it causes tranny to whine. Anybody?

Additional info from Motul Espana: Motul does NOT list Gear 300 for 2005 - gear boxes.

Details on Shell Spirax S5 ATE which replaced Shell Transaxle Oil:
http://www.epc.shell.com/Docs/GPCDOC...1008230850.pdf
It is available in 20L pails in Western Canada. Not sure about other provinces and states.
It is Porsche and Ferrari approved.
=L=

simsgw

I thought the current transmission was manufactured by ZF rather than Aisin. Was I misinformed? Or did that change with the new engine in the dot two?

No problems or even early warnings from our transmission, but that may not be an indication since I'm pretty easy on synchros.

Gary

alexb76

I think ZF only makes the current PDK and will be making the 991 PDK and Manual.