dhsieh

I contacted L&N Engineering, a Porsche tranmission shop known for its IMS Retrofit Tool Kit for 996 and some 997. According the email I received from them:

Is your transmission fitted with limited slip? This would change my recommendation. The Delvac 1 is the correct fill for a non limited slip transmission. Currently we do not have any products in stock for transmissions for limited slip, but within a few weeks we will be carrying several Millers products.

Charles Navarro
LN Engineering
http://www.LNengineering.com

This person cited Mobile 1 Delvac to be the correct fill for my 08' Carrera S since I don't have limited slip option.

alexb76

Ok, I am really confused now... WHY do you care which fluid to use, when you got access to OEM, it works perfectly fine on the street, and it is not that expensive?!

I got some shifting issues on track after the car gets really high and hence been looking for an alternative when I flush, but if I didn't track, I'd just fill-in with OEM and forget about it!

dhsieh

Well, it wouldn't hurt to have 2nd opinions. The bottom line is that for my '08 Carrera, I'll use OEM since the car is still relative new and I plan to purchase extended warranty after the manufacturer warranty expires. But after extended warranty, I really like to find a suitable substitute for OEM. After reading so many threads from different Forums, I am more confused on this simple inquiry than I started ...

equ

As another somewhat different data point... I changed my transmission/differential fluid in my cayman at 30k miles. Shifting improved. I used OEM (mobil 1 I think). YMMV.

mattyf

I'm also interested in the experts advice. I was thinking about changing mine to Redline 75W90 to help with notchyness:

http://www.redlineoil.com/product.aspx?pid=47&pcid=7

some not so old thread on the subject:
https://rennlist.com/forums/997-foru...at-to-use.html

Luxter

This subject has been covered extensively in the past.
First of all, Carrera and Carrera S are equipped with Japanese Aisin Seiki (Borg Warner) transmissions that are not the same as GT2/3 cars. They are actually made in Japan (have a peek under your car). Aisin uses steel synchromesh cones and 2nd gear in particular is known for being the misbehaving child. Therefore Porsche approved gear lubricant(s) that deal with this issue of acceptable meshing lower gears and provide adequate protection to the rest of box components such as actual gears and hypoid final drive. There are a lot of compromises that needed be from lubrication perspective and I am not a tribologist!
Porsche only approved one lubricant that I am aware of, that is Shell Transaxle 75W-90 which has been superseded some time ago with Shell Spirax S5 ATE. It is also approved by Ferrari and Maserati.
Some properties of Spirax are listed below:

Spirax S5 ATE 75W-90
SAE Viscosity grade SAE J 306 75W-90
Density at 15°C kg/m3 ISO 12185 879
Viscosity at 40°C mm2/s 81.0
Viscosity at 100°C mm2/s 14.9
Viscosity Index ISO 2909 194
Flash Point COC °C ISO 2592 205
Pour Point °C ISO 3016 -45

For daily driving, that’s your best lubricant available. Either pay Porsche ransom for their fluid or try to find Shell Spirax S5 ATE in your own time (good luck with that one) or source Shell Racing Gear 75W-90 Lubricant from Europe. They are all the same.
There is another lubricant that I found recently that is very similar to Shell. It is Liqui Moly GL-5 75W-90 fluid. Here are some properties:
TECHNISCHE DATEN:
Viskositätsklasse : 75W-90 DIN 51512
Dichte bei +15°C : 0,870 g/cm³ DIN 51757
Viskosität bei +40°C : 82 mm²/s DIN 51562
Viskosität bei +100°C : 14,5 mm²/s DIN 51562
Viskositätsindex : 185 DIN ISO 2909
Flammpunkt : 184 °C DIN ISO 2592
Pour-Point : -43 °C DIN ISO 3016
ASTM-Farbzahl : 2 DIN 51578

Friend of mine runs it in his 1999 Carrera, but his gear box is actually made by Getrag, so we are not comparing apples to apples. It shifts OK from what he is telling me.
None of major German blenders (Fuchs, Liqui Moly, Pentosin) even recommend any of their fluids for 997 gear boxes. That doesn’t sound right, I know. The Germans don’t have proper fluid for their own brand? Sounds ridiculous but it’s true! We can speculate on that later.
RedLine 75W-90 NS isn’t that far off from Shell, but its viscosity index is at 176, nowhere near Shell lube and viscosity at 40*C = 95, well above Shell.
It gets even worse with Mobil 1 Delvac so your cold morning shifts will be notchy and I can attest to that. I had it in my box and it is gone now. Cold mornings were just too harsh. On the track however, I have no doubt that it will perform very well.
Another lube: Motul Gear 300 75W-90 with its massive viscosity index of 222, viscosity at 40*C = 72.6 may be a good fit, however some say that it causes boxes to whine. I have no experience with Motul.
Happy motoring!
=L=
Oh, one important note. The above applies to boxes WITHOUT limited slip diff.
If your car IS equipped with LSD, don't screw around with gear lubricant and go straight to your favourite dealer to get the right fluid.
Cheers.
=L=

dhsieh

Thanks to Luxter's excellent posting on this topic. Here are some takeaways on my part from his insight:

(1) Japanese Aisin Seiki (Borg Warner) transmissions in Carrera? The 01' 996 I had before its 2nd gear sometimes would pop out and I couldn't believe that a Porsche would have such a problem. With my 08' 997, I still can feel its 2nd gear to be awkward to engage and it only has 23k miles on it
(2) I'll use OEM oil when my Carrera S is still in warranty. Looks like in US, other available options would be either Liqui Moly (one of my Porsche mechanic's recommendation) or Motul. I hope whoever uses them can share their experience with your fellow Porschephile

Luxter

Folks,
I actually have Liqui Moly GL-5 in my gear box now. Just got it in. Will post my experience, but it's going to be a while.
New coolant pump, 160*F T-stat and 3rd radiator and fresh coolant need to be installed first.
In addition, shifter cables will be re-adjusted as well.
So, give me a couple of weeks in my garage and hope for good weather as well.

I am really curious about Motul Gear 300 75W-90. Has anybody tried that lubricant at all. Please post your experience.

Cheers,
=L=

Aerokitted

Sorry for the sidetrack, but as a service to you and others, you should consider buying the aftermarket warranty via Porsche dealer before your warranty runs out or ASAP. The risk they take on becomes greater as the car gets driven more or ages.

You are also more leveraged when you don't have the factory warranty any longer.

If you have $5K burning a hole in your pocket, get it done now to lower the cost. The warranty package is highly negotiable.

And with gear oil, I see no reason why to find non-OEM oil. It's proven and blessed by Porsche and the $ savings amounts to ordering an americano instead of a latte for a month on your daily visit to the cafe.

dhsieh

I am actually already in the process of calling local car dealers, including Porsche, in my area who carry Fidelity for quotes. One thing I find really annoying is that they are not forthcoming. For one, they almost never provide you with a written quote as if there are some dirty secrets in this business ...

alexb76

AWESOME Infomration... I remember we did talk about transmission oil a few months ago, and I think you were left to try Delvac.

So, what do you use now? OEM or Shell? or else?

alexb76

Why are you trying to re-adjust them? and how?

I got some shifting issues and eventhough my center console is off, they're telling me there's no way to adjust them?!

Luxter

Yes, we spoke before on this very subject.
M1 Delvac is out. Shifts were too notchy in cold. Good for track for sure and I know you want a good track day lube.
Liqui Moly is in, but not driven on it yet, so no comments so far.
Ultimately I will try to use Shell. Either from Europe or locally.
Aston Martin uses Shell as well. They import it from GB directly and for less (quite a bit less in fact) than P ($28/L vs $48/L).
Just refuse to pay $48 / L from dealers.
One issue with Shell is that the Transaxle was fully synthetic, Spirax is HC technology. Probably not a big deal, but Liqui Moly is fully synthetic. Give it a shot on the track, see how it performs.

Why adjusting shifter cables? To make sure that the cable adjustment is not part of the problem.
Pelican sells part #: 000.721.961.91 for 997 shifters and
part #: 000.721.961.90 for 996 shifters. Both parts are under $5 each.
Procedure? Easy, remove center console, shift to neutral (tranny must be in neutral), disengage both cables, lock the shifter with the bridge from Pelican, snap cables in place, re-assemble all.
Basically, you make sure that tranny in neutral matches ****er in neutral by adjusting cable lengths. It all sounds more complicated than it really is.
Any questions, fire away...
Cheers,
=L=

Luxter

Alexb76:
Just one more comment RE: M1 Delvac.
I am familiar with your climate. If you get into heavy city traffic right away as you leave home, you will not be happy with heavier shifts on M1 Delvac. If you however can afford to warm your car up away from heavy traffic, you will be fine then.
I live in area that I can afford to drive on country roads for a bit just to warm up the car enough to hit either traffic or hwy.
You just have to try and see what fits your bill.
Keep in mind that track puts a fair ammount of wear on your gear box. So, either change gear lube before and after track days or accept limitations of heavier lubricant in daily driving.
There is no other option that I am aware of.
Cheers,
=L=

Spokane5150

My trans is a little notchi when cold but shifts like butter once the trans is warmed up.