Motul 90PA SAE 90 Gear Oil

[big911fan]

I don't want to start the holy wars on gear oil again but I've looked through many of the posts and haven't seen any reference to using Motul PA90 in a G50 LSD transaxle. It's a mineral based product made for LSD gear boxes and was recommended by a professional P-wrench.

The Motul products all seem to be good products and I'm trying to reduce the "notchyness" of my factory short shift G50 with LSD.

My current fill is Redline 75W90 synthetic. Maybe the notchyness is the nature of the beast but the car only has 34K original miles on it. Doesn't feel like worn syncros at all. Just hard shifting which rev matching and/or slow shifting minimizes.

If anyone has experience with Motul PA90 I'd appreciate the feedback. Thanks.

[88-diamondblue]

Never seen any posts on Motul gear oil since I have been here. Factory fill for Porsche Motor Sports is Delvac 1 by Mobil formerly known as Delvac SHC and is a synthetic. They are used on the GT 2 and GT 3 cars with LSD. Try the Motul as you can go to the Delvac for around $50. Let us known how it works if you decide to use it.

The other possibility is the shifter ball needs replacing or check the connection behind the back seat to make sure it is tight and adjusted. My G50 shifted better after my engine drop so alignment can be an issue. Mine came with factory short shift but no lsd.

[big911fan]

I don't think the shifter ball is worn because the mileage is so low. I've been told that the short shifters can be notchy by nature but I've never owned a short shifter before. I had an '87 Carrera with a standard shifter that seemed much better than the short shifter.

Maybe I'll try the Delvac 1 since more people have experience with it. I'm surprised no one has had experience with Motul 90PA though since Motul products get a lot of track use.

[big911fan]

Just checked the LN Engineering site for Delvac 1 and found that it's not recommended for LSD. Here's what they say:

"We recommend this gear lubricant in G50 and later manual gearboxes (or any gearboxes calling for a GL5 lubricant) for both aircooled and watercooled Porsches without limited-slip differentials. "

Guess I'll keep looking.

[88-diamondblue]

You might email or give Charles Navarro a call at LN for some recommendations. They have done a lot of work with many different oils.

This is what is posted at the LN engineering site as well as what you said above

"Another favorite of mine is Mobilube SHC 75w90 (now known as Delvac 1 75w90), not to be mistaken with the Mobil 1 gear lube found at your local flaps. This stuff is the factory GL-5 fill from Porsche in all their race cars and is an industry standard in semi / mixed fleets. You cannot go wrong with Mobilube SHC or its Delvac 1 branded replacement."

Porsche race cars would have LSD's in them.

Check this out on what they say in their description. Another recommended supplier. http://www.lufteknic.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=Mobil75-90delvac&Category_Code=lubricants

[big911fan]

I'll take your advice and email Charles Novaro about the Delvac 1 comment on his site about not being used in LSD gear boxes. The site you referred me to clearly states that it is. Conflicting signals I guess. I would prefer something made for LSD's rather than adding supplemental friction reducers.

If Delvac 1 can be used straight from the bottle I think I'll try it.

[big911fan]

I went directly to the Mobil Oil site and here's what they say about LSD gearboxes and Delvac 1 75w90:

"02/18/2009 Which Gear Oil Brand is Best for Porsches with Limited Slip Transaxles?
For Porsches with limited slip transaxles, I've heard that Mobil 1 Synthetic Gear Lube LS 75W-90 is too slippery for the synchros and that Mobil Delvac Synthetic Gear Oil 75W-90 is the preferred lube....

A: Mobil 1 Synthetic Gear Lube LS is specifically designed for limited slip differentials. It contains a nominal amount of friction modifier to satisfy the needs of many applications. Mobil Delvac Synthe... "

Looks like Charles Novato's site was correct. Delvac 1 75w90 is not for LSD gear boxes. They should use Delvac LS 75w90.

[88-diamondblue]

Great to know. I went out to Mobil to look at their site and it can be tough to find information there. Let us know if you use it and how it works,

[ix0ifan]

I have been using Redline 75W90 NS GL-5 Gear Oil with good results for several years.