I have searched for Transmission lube, and have gotten some posts from about a year ago. I am wondering if people have opinions on the Mobilube SHC75W-90... or an alternative?

Shifting has gotten a little notchy.. and there is a fair amount of chatter in second gear at low revs.

What's your favorite gear oil if this isn't it?

TIA...

 

That is the gear oil I prefer.

 

I think the one you're talking about is no longer in production. This is what I use: http://www.mobil.com/USA-English/Lub..._LS_75W-90.asp

 

FWIW.. I found it here too: http://www.pfifilter.com/compressoroilpartnumbers.php

 

Cool.. where did you get it?

 

Ebay

I think I used this exact vendor, too: http://cgi.ebay.com/Mobil-1-75W-90-S...QQcmdZViewItem

 

Ilko, that is the standard off the shelf 75/90w oil you can buy at Autozone. It has LSD friction modifiers in it and tends to be too slippery for the syncro to be able to grab the gear and spin it up. You'll notice more difficulty shifting. The Monolube SHC, now called Delvac SHC is the latest gear oil that Porsche has been using in the Cup car boxes.

 

Thanks Geoffrey, I wasn't aware of that. I'll add transmission fluid change to my winter to do list

I did a quick Google search and Delvac SHC only seems to come in 5w40 formula as engine oil. Any idea where to get the 75w-90 gear oil? I've only found European vendors so far.

 

If your trans is shifting fine, then I'd leave it alone.

 

The SHC is still listed on a parts list at this vendor: http://www.pfifilter.com/compressoroilpartnumbers.php
I have put in an info request, and we'll see if they have it in stock.

 

http://www.lufteknic.com/Merchant2/m...ode=lubricants

also see: https://rennlist.com/forums/showthre...l+gear+oil+cup

 

964 and 993 owners that don't run steel syncros have had better luck with Mobilube PTX. A few with the same problem as you tried SHC/Delvac and then had to switch to PTX to "fix" the problem (my winter project). How's the condition of the slave cylinder and brake fluid?

 

Slave is new as of September, with the accompanying bleeding (knuckes and ATE superblue)
The reason I also ask about lube is the fact that the car makes a whirring/shirring sound in second gear, under very light load (driving up my street).. which sounds very gear boxish.. like an old tranny from a 50 pickup I have...

I could simply be low on oil.. I haven't checked it

I can get a case of the MobilLube SHC 75W90 from a food equipment supplier.. $86... which is about 4X than what i need.. anyone in the PDX area want to share?

 

Jason wrote:
964 and 993 owners that don't run steel syncros have had better luck with Mobilube PTX


I have steel syncros, why should I not use Mobilube PTX 75W-90 ?

Sten

 

I don't know of any reasons not to use PTX, I just know that problematic gearboxes with stock syncros have worked better with PTX than they have with SHC/Delvac. As mentioned by Geoffrey, Porsche Motorsports (and their gearbox rebuilder in NA) fills their steel syncro transmissions with SHC/Delvac.