The previous messages are correct in saying that heat is the great enemy of AT transmissions. That's why RV vehicles and trucks have separate transmission oil coolers. Does your turbo model have the locking torque converter? If so, this tranny stops generating heat after lockup and the tranny should run cooler on the highway as long as the tranny is in OD and you're over 45 mph.

I don't know if this means synthetic would be wasted in this case. I'd think there would be more than heat resistance as a benefit of synthetic. There is with engine oil.

Greetings, I agree with these other post that synthetics reduce heat(biggest enemy of an automatic transmission) and wear, plus shifting seems to be better, crisper, more defined. Not to be knocking Mobil 1, I have used it quite a bit in previous racing conditions. But, I have been using Amsoil synthetics for over 15 years and I am convinced there is nothing better available on planet earth. Go to www.amsoil.com and you can order online or send me an email and I can send you a dealer packet and you can sign up to be a dealer of your on as I did many years ago.
Good Luck, Walt
'96 964 141k, AMSOIL SYNTHETICS ONLY!!!

I'm using the half and half stuff, mostly cause I can get it on sale. I have difficulty rationalizing the cost of full synthetic when I flush it out every 20 - 25 kmiles. Just my opinion, although I use Mobil 1 just about everywhere else, it's great stuff. Tranny shifts like a dream at 130 kmiles. I think the key with auto trannies is to keep the juice clean......time will tell.

I use Mobil 1 Synthetic ATF ($5 per quart) and find it fantastic stuff. I've used it in eight cars and it has worked like a champ. Minimizes wear in the tranny.

I've had very good results with Mobile 1 Synthetic ATF. You may want to get a new pan gasket and drop the pan. Clean out the gunk and clean up the pan magnet. Flush the tranny ... You should find good instructions on the procedure in the 700/900 FAQ or in the archives, not sure which, but it's there. I also use Mobile 1 ATF as my power steering fluid. Good stuff. You might consider adding a container of Lube Guard to the ATF juice. Most additives are "snake oil" but this stuff really seems to work ... cooler running temps and less wear. A lot of autobox rebuilders put a shot of this in with the new fluid. I get mine at a wholesale supplier of transmission parts and kits for rebuilders. About nine bucks but IMHO well worth it. Hope this helps.