manual gear oil suggestions?
 

I was going to change my gear oil in my 2002 S manual this weekend, but I can not seem to find two people that agree with what to put in there.

the car has 65K miles and I drive in south texas heat.

What brand and weight oil would be the best regardless of price?

Also does anyone have a DIY link for this?

thanks,
James

Call Sunset (503-641-8600) as they usually have a little better pricing:

http://www.e-partssales.com/miva/merchant.mvc?Screen=PROD&Store_Code=P&Product_Code =99991754600&Category_Code=986Tran

There is a basic reason why you cannot get agreement on what type of gear oil Porsche uses; because they use a totally unique product that is made just for them. As the result, most major gear oil companies (the truthful ones anyway) simply say they do not have a suitable replacement, while the hucksters will tell you theirs is a perfect substitute……

Knowing how much these gearboxes cost, and that the OEM fill is a readily available and inexpensive full synthetic product, going to Sunset and buying the OEM fill is your best bet.

There has been a lot of postings on oil and some are pretty comprehensive. I remember reading a great one by Charles Navarro on why he does not recommend oil but if you go to LN engineering's site you will see what they think is good enough to distribute.
I replaced mine recently with Royal Purple and ran TTs, AXs and DEs without any noticeable difference. (I'll try Motul next).
For the DIY, Bentley's is your best help. Not too bad of a job (Except measuring the oil level).

What??? :confused:

Jhandy is asking about manual gear oil....not engine oil. And yes, Charles clearly recommends specific oils on his web site. Did you read his entire "Freq. Asked Questions" link? Excellent reading. You will see that he recommends specific oils, and recommends oils to shy away from (like Mobil 1).

The OEM fill on race cars from the factory used to be (and might still be) Mobil 1 SHC, which was rebranded under their industrial lube name Delvac 1. We've used it for years, when it was only available in 55 gallon drums. I used to even bottle it for customers, until Mobil started offering it in gallon jugs. It's different from the M1 gear lube found at Autozone, etc., and I've used and recommended it for years.

Charles, an interesting response, particularly in light of the fact I had read the same explanation elsewhere and asked our Mobil rep about it some time ago, got a totally confusing answer and then was referred to their “technical group” who responded, “Mobil no longer produces a suitable gear oil for the Porsche transmission. You should consider contacting a Porsche dealer for an appropriate replacement.”

Any thoughts?

I would file that response under the cookie cutter answer. If I ask my Mobil rep, they wouldn't know what a Porsche was :-) - just a bit of an exaggeration, but you get the point.


Since the gearbox is sourced from VW/Audi, it would take the same fill and their lube may be a fully-synthetic GL-4 rated gear oil. There are VERY few true GL-4 oils available, most out there are GL-5 rated (which is supposed to be backwards compatible).

The tip's differential on the other hand calls out specifically for a GL-5.

Technically, any 75w90 or 90WT GL5-rated gear lube should meet the requirements for the gearbox IMHO.

It's best to google about vw/audi gearboxes rather than Porsche ones, since you'll find a lot more information and discussions about the vw/audi counterparts to the Porsche ones.

I have less respect for Mobil 1 everyday............

Just for informational purposes, Red Line continues to offer a good selection of GL-4 full synthetic gear oils. Reason I know this is that Nissan continues to require GL-4 gear lubes and the syncros (and some bearings) they use don't seem to last very long with GL-5 oils. We've used the Red Line GL-4's in our client's Nissans with great results.

For what it is worth, under the API specs, the additives’ that make a gear oil a GL-5 should make the oil incompatible with a GL-4 gear box. I know some oil companies have claimed to have oils that can be used in either one, but having seen what a GL-5 oil does to the internals of a GL-4 Nissan gear box, I really wouldn’t trust the claim that a GL-5 is always backwards compatible………….

I saw this on another site, you may be interested:


https://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Group_3_Base_Oils.aspx

Not exactly "news", they have been doing this ever since Exxon acquired Mobil in December of 1998, which is why the performance of their oils has deteriorated so much since the acquisition, and why some grades no longer carry ACEA ratings……..

We do have some decent long term testing on the Delvac 1, for what it's worth, with the aircooled guys. Many tranny rebuilders, including Guard, recommend it.

Amsoil also makes a GL4 oil, that I used to use in 356 and VW gearboxes before switching to Swepco 201, which anyone before a 915 gearbox swears buy. It's also a GL5 rated oil, for what it's worth.

Interesting you mention Nissans - one of my customers mentioned their use of Motul in their race trannies (and engines) with excellent results.

Can honestly say that I have no history with Mobil Delvac synthetic gear oils, in fact, I don't know who even sells them. Did a quick online search, lots of data but nothing on were to buy. I'll have to make some calls in the morning.

Motul has several interesting products, only problem is that they tend to be very expensive to buy unless you get large quantities, kind of restricting. I've used their stuff as well, and it was fine, albeit pricey..........

Never been much of an Amsoil fan, but only because of their weird MLM-like distribution system, and because history has taught me to shy away from small blenders and stick with larger producers.

I did find that Mobil does make a Delvac 1 synthetic transmission fluid 50, which is equivalent to a 90WT, which carries a GL4 rating, which is also now available in gallon jugs. Something worth asking your Mobil rep about.

Always use the OEM lube from Porsche.
It is formulated with all the correct additives to get maximum use of syncros.
If a lube is too slippery, as many are you will get an occasional grinding in second mostly however it can occur in other gears too.
When it grinds you are damaging the cogs on both the gear and syncro.
Eventually it will always grind and subsequently slip out under a load.

A GL4 is what to use and if you contact Mobil you will find they tell you not to use their GL5 product.

Replacing the lube under 100k is usually a waste of time and money anyway.

Based on what?

actual experience

I have seen transmissions, both automatic and manual, limited slip differentials misdiagnosed because wrong fluids.

I realize oil and other topics are passionate subjects for some with strong preferences however take what I said as not personal preferences.

OEM transmission lube is the best all around lube for all around driving in a modern Porsche and many other brands.

You just have to be knowlegable about lubricant choices, that's all.

Mobil's Delvac 1 isn't formulated for limited slip differentials. And yes, they do make a GL4, but again, it's not something found at your FLAPS.

As far as drain intervals, if you ask a performance transmission builder that does Porsche gear boxes, I'm sure they'll tell you to change the gear lube more often than 100,000 mi. That's way too long. If you track the car, it should really be done at least every year. Same goes with the ATF on Tip cars if tracked.

If not tracked, I would take Porsche's recommendation and cut it in half, at the very minimum.

It's interesting to see manufacturers like Kia with their very good extended powertrain warranties and see on how short their drain intervals are.

"I realize oil and other topics are passionate subjects for some with strong preferences however take what I said as not personal preferences.

OEM transmission lube is the best all around lube for all around driving in a modern Porsche and many other brands."


Again, I fail to understand how the above statement can be made and not seen as "personal preference."

Unfortunately, lubricants – much like politics or religion – appear to be a difficult subject to have a dispassionate or objective conversation about…………. :cool:

I replaced the gear oil at 60k miles in my Mazda with Royal Purple and I'm satisfied with the purchase. It's slighty smoother especially when cold. The shifter feels like a warm knife cutting through hot butter. I just wish the shifter in the Boxster felt half as positve, smooth and easy to shift. Since it yielded an improvement in the Mazda(even though it shifted well from the start) I might try it in the Porsche if they offer the correct weight.

Quote:

Originally Posted by Brucelee Again, I fail to understand how the above statement can be made and not seen as "personal preference."

Its information found in the Porsche manual, not in Frank's manual.

Also the original post was for a vehicle used in everyday service, its not a track vehicle.
Porsche's recommendation are not for track vehicles, and neither are mine.
You are on your own with a track vehicle.

I'm checking into gear oil for the Porsche trans and I'm on Redline's site. They recommend their GL-5 75W90 oil for Porsches not the GL-4. This is contradictory to what some of you are saying. I'm confused. :confused: Here is the link.

http://www.redlineoil.com/Products.aspx?pcid=7

The problem is that you would normally use a GL4 in the transmission, because as I understand it most GL5s are corrosive to the soft metals found in there (copper, brass). However, the Boxster uses the same lube in both the tranny and the differential, and the diff has hypoid gears.

Redline specifically says that their MT-90 GL4 is *not* for use with hypoid gears. They also say that their GL5 is formulated so it is not corrosive to soft metals. That's why they recommend their 75W90 GL5 for the Boxster.

Having said that, I was told by a 'reliable source" that the MT-90 was just fine to run, and I did. My shifting smoothed out, and I never had any issue with gear noise over 20k miles of use. But if I still had the car I'd swap it over to the GL5 lube, just in case.

That's what I needed to know. Thanks for the info Jack.

I wouldn't trust it.
Suppose one of your syncros fails and you get an occasional grind.
It will cost mucho bucks to fix.
I would buy the Porsche lube to have piece of mind rather than experiment.

My mechanic is a Porsche certified tech and put Royal Purple gear oil with the appropriate weight in my 5 speed manual tranny after I swapped it for one that had a bad 1st gear synchro.

Boy howdy, if you want to kick up a dust storm, just ask about oil or tire preferences on this or any sports car forum!

Thankfully, most all of us agree on the best fuel to put in the car...

I still stick with the engineers.

Techs have opinions and usually not accountable, engineers are accountable.

I can hear a tech saying your syncro is gone because you mashed gears.

Well the gears will mash when the syncro does not bring the new gear up to the same speed as the driver gear. This causes damage to the syncro cogs.

I understand your position, except:

RMS seal failure. IMS bearing failure. D-chunk cylinder liner failure. Premature AOS and oil filler tube failures. Rear axle bearing failure. Etc, etc,...

All Porsche engineering failures. And they have NOT been held accountable.

All things have flaws and failures.

Imagine if techs designed cars.
Would anyone want to fly in an airplane designed by engineers or mecahnics.
Who would drive on a bridge designed by excavators.
Who would want to have their teeth drilled by the dental assistant..

All true, but...

Porsche doesn't "design" oil. They don't manufacture it, or even package it.

The guy that designed the tranny writes up a spec for it, and the lowest bidder gets a contract to supply it in a bottle that has the Porsche name on it.

Redline engineers design and produce nothing but oil. That's their field of expertise.

Hmmm... in a way, the Porsche oil is a bit like the bridge that was designed by the excavators.

YMMV. :cheers:

Then why do lubes have a manufactures spec?
such as :

Mobil 1 0W-40 keeps engines starting in Arctic-extreme cold, and it cleans deposits, sludge and varnish often formed in high temperature operating conditions.

Mobil 1 0W-40 meets key industry and car builder specifications for:

− Mercedes MB 229.5
− Porsche Approval List 2002
− GM-LL-A-025 (gasoline)
− ACEA A3, B3/B4

− BMW Longlife 01
− VW 502.00/505.00/503.01
− GM-LL-B-025 (diesel)
− API SM/CF

It's called marketing.

Notice how Mobil 1 meets so many specs? That's because there's not 2 cents worth of difference between them, and it's not rocket science to meet them. But, as we know when it comes to getting a manufacturer's blessing (think Porsche approved tires), there's a cost involved in getting that blessing. Not having it doesn't mean you don't meet, or exceed it. As a manufacturer of oil, you pay for the privilege of putting that spec on your bottle. It's about money.

I hope this isn't developing into an AMSOIL or REDLINE thread. :eek:

Lord, no. Wouldn't want to steer it away from the "OEM only" thread it's become! :D

This statement officially says nothing. No substance, just drink the kool aid!!