Perhaps, but it's what I read here is supposed to be the proper factory type fill. It will if anything give me a baseline to work from in trying other gear oils like Redline, etc. As I mentioned, I have no idea what is in the case now or even if it has ever been changed.

 

Whoever posted that information was incorrect. After long term durability testing in 1998, PAG pulled the GL5 recommendation and went with Mobilube PTX or Shell Spirax S5 75W-90. From the experience of many, we know that Delvac/SHC does not work as well in a regular 964/993 G50/G64.

 

I have Mobilube PTX in my car now. https://www.suncoastparts.com/product/00004320420L.html
It feels really good once warmed up. During cold shifts it can be a bit challenging.

I still think the OE Porsche fill is the best all around fluid https://www.suncoastparts.com/product/99991754600.html

My.02

 

I’m guessing synchros, based on the symptoms you’ve described. That would explain why it’s tougher to shift when the car gets hot. Steel synchros may be in your car’s future.

 

That’s interesting. I’ve never heard that. Delvac will crunch on the 1-2 when cold. Shifts great when warm. I’ve also tried Swepco and wasn’t impressed. Running Porsche gear oil now and I’m very pleased. No crunch, grind or noise, hot or cold.

 

Had issue with Lucas when cold and Cold like Frosty cold...where is OP?
at what temp is issue?
Did u test engine mounts? Sagging tips?
have you cleaned shift linkage ? After removing ice :>}

 

I run the Redline 75W 90 in both my 1988G & 993 C4S and with great success. Frankly, I have the Mobilube PTX on hand and may drain/fill 993 C4S with it but just to try and see how it is vs. Redline.

 

worthless post, but imagine what you'd come up with by searching this topic on social media... a sign of the times.

 

For another data point, on my 96 C2 with an LSD, I refilled my factory-fill with SWEPCO 201, it was colored blue, and shifting was the same as before - like buttah.

With that said, I've always double-clutched all downshifts, so my synchro's love me.

 

i have new engine mounts and golden rod, short shift, and all replaceable shift bushings
when I drive for a while in hotter weather ( was 30-40 C here for most of the summer) and motor gets closer to 3 or 4 o’clock temp. this is when miner grinding occurs, shifting also feels loser
I’m using Castro 75W-90
cheers

 

I think I’ll give this Mobillube PTX a go first
thanks for the feed back