I've read a few posts. General consensus seem between Swepco 201 or Mobil Delvac 75w90. With some worrying about winter and thickness of the Delvac. Some people use Redline MT 75w90.

(I have 4 quarts in my garage and was going to drain my fluid but figured I would ask first in case it's totally the wrong tranny fluid for my C2 5spd)

I am not a lubricating oil analysis expert but have usually used Pennzoil Syncromesh with my VW's and AUDI's as it was easy to find at the local store and was highly recommended by most local racers (most of them did drive domestics) but I've never had wear problems.

Pennzoil Syncromesh states that its:

Excellent synchronizer performance.
Excellent yellow metal compatibility.

http://www.stealth316.com/2-pennzoil-synchromesh.htm

 

Not familiar with that one. I know oils are a cultish thing... I just use what the builders of these transmissions tell me they see good results with.

You'll see devlac, swepco, millers, motul, lubrication engineers on the list...

I've recently tried motul 75-140 in my GT3RS and have 6 track days using it. It performs as well as delvac hot (shifting performance) and shifts nicer when cold. Price is about same as Delvac (60-80 / gal)

Oh and change it often if you're tracking the car.

 

Steve Weiner says Delvac 75w90, thats as good as Porsche recommends to me. I wouldn't risk this pricy of a transmission over a few bucks.

 

I've tried Swepco and Delvac in the 993 and shifting was very notchy and difficult on cold days. Made the switch to Redline NS, and no issues since then. My 964 is too new to me, not quite sure what's in the tranny.

 

I have heard that delvac is great but causes notchy shifting when it doesn't warm up, and this is more noticeable in cold climate. I see that you live Maryland

 

I go with genuine Porsche trans fluid. No notchiness either hot or cold. A little pricey but the feel and peace of mind are worth it. I do not track my car but it is a hard driven daily driver. I have used delvac in the past. I recall a bit of notchiness when cold but otherwise a good choice and cheaper than oem.

 

It's not about saving a couple of bucks as Syncromesh isn't much cheaper than Delvac or others. It's the fact that Syncromesh is an OEM fluid and should be fine for many manufacturers. I agree that most lubricants are cultish thing.

I used Syncromesh because locals that raced recommended it as it was easily available and and usually used Redline when you needed something thicker. I never had issues with my VW's and Audi using Syncromesh lubricant and wondering if anyone had any experience.

I have 4 quarts sitting in my garage and my DD isn't a manual so I'll end up giving it away or using it.

 

The Porsche transaxle require a GL-5 transmission oil. As far as I can see, the Pennzoil Synchromesh is NOT rated as GL-5, so I would definitely not use it in my transmission.

PS: Did a bit more poking around, Pennzoil Synchromesh is a GL-4 oil, so not recommended for our Porsche transaxles.

 

Great! I'll pass my Pennzoil Synchromesh to one of my VW buddies. I couldn't find that it was GL-4 or any GL rating for that matter.

 

since this year, i use Castrol SYNTRAX LIMITED SLIP 75W-140 in my G64.00 box. Quite good. Shifts better when hot at track and shifts not that bad in cold conditions (as it was with other fluids). In the G50 from my convertible i`ve a standard GL5 fluid from a cheap brand.. No issues so far for normal road usage... But i change my gearbox fluids quite often.

 

Another happily using Castrol Syntrax 75w140. Keeps the LSD plates happy as well as the gearbox...

 

Really?! Who else uses this oil? I'm intrigued now. I was all set on 75w90 delvac