Gear Oil Recomendation for New Zealand

[creaturecat]

i run the Motul Gear 300. i'm pretty happy with it. non lsd

[Matt Monson]

Originally Posted by daltvater

Thank you Matt! I would not have figured this out without your suggestion here. Motul has so many choices and isn't very helpful when asked about which to use.

Just to confirm this looks like the stuff....
https://motul.co.nz/product/hd-80w90/

Correct. That's what I would use.

The only other thing I will add is that there's shift quality and there is wear. Some of the synthetics will feel great when the gearbox is freshly rebuilt, but they will accelerate wear, and if we bump this thread in a couple of years, it wouldn't surprise me if some of these people have needed to refresh their box because of worn synchros.

[MBEngineering]

what LSD are you running, plated or ATB?

[daltvater]

Originally Posted by creaturecat

i run the Motul Gear 300. i'm pretty happy with it. non lsd

Great news to read this. So I didn't ruin the thing by using the gear 300. Thanks for the piece of mind! This would have bugged me.

Originally Posted by Matt Monson

Correct. That's what I would use.

The only other thing I will add is that there's shift quality and there is wear. Some of the synthetics will feel great when the gearbox is freshly rebuilt, but they will accelerate wear, and if we bump this thread in a couple of years, it wouldn't surprise me if some of these people have needed to refresh their box because of worn synchros.

I'm following your lead on this one Monson. The HD 85w 90 feels like the oil for me. Its also like half the price of Motul Syn. I've been replacing it every 350 track miles which is about 4 good days at our local track here. (Hampton Downs) No clue if that is too much or too little?

Thanks for all your help, much appreciated! I'll report back if I notice any differences after next weeks track day!

Originally Posted by MBEngineering

what LSD are you running, plated or ATB?

Plated I think? Its a ZF I know that. I also remember the shop talking about plates and that my lsd is very tight even though they tried to loosen it up.

[Rosco_NZ]

Why not Penrite products?

[OSC911]

Good point. I run the appropriate Penrite transmission oils in both my 915 in my ‘76 and the G50 in my 993. Zero issue with shifting and meets all the GL4/5 specs.

[daltvater]

Originally Posted by Rosco_NZ

Why not Penrite products?

Car has a freshly built 3.6. Had Mobil 1 20w 50 in it. Swapped it for Penrite 20w50 (because it was cheap and easy to get) Engine started smoking like crazy. Local shop carries Brad Penn 20w50, put that in, smoke stopped in minutes and hasn't been seen since. Maybe I got 10 bottles mislabeled with the wrong viscosity or something Local Porsche gurus gave me **** for putting Penrite in it. For all I know its great stuff but I'm new to NZ and will forever be suspect of Penrite

Shop in Auckland has a line on some Motul HD 80w90. Going to give that a go. With a little luck I should put 100 laps on it at Hampton Downs before the end of the year!

I'll report back on any perceived difference.

[Bill Douglas]

Originally Posted by daltvater

Swapped it for Penrite 20w50 (because it was cheap and easy to get) Engine started smoking like crazy.

I've been using Penrite 20w50 for years in my SC. Years and years. And no smoking or odd things happening. It's got the extra zinc too.

[daltvater]

Originally Posted by Bill Douglas

I've been using Penrite 20w50 for years in my SC. Years and years. And no smoking or odd things happening. It's got the extra zinc too.

Just one of those things I suppose. Leak down last week was 2% across all 6 so I rarely see smoke. The amount of smoke after the Penrite was no bueno. No heat exchangers, no spills, just light smoke pouring from both pipes. annoying enough to ban Penrite for the old girl.

[Bill Douglas]

Just one of those odd things I guess. I've bought some Penrite HPR 15w60 full synthetic for the SC. Do you think that will be OK?

[daltvater]

Originally Posted by Bill Douglas

Just one of those odd things I guess. I've bought some Penrite HPR 15w60 full synthetic for the SC. Do you think that will be OK?

You don't want to be taking oil advice from me mate For all I know I put the wrong Penrite into my oil tank.

I'm sure you will be good with the synthetic! These engines are like tractor engines, they don't seem to care about much.

[Bill Douglas]

LOL yup, I'm sure I'll be fine.

[Schulisco]

Hi there.

I can only recommend to follow exactly the recommendations from Porsche! Compare the values / tech. specs from the oils! Porsche says for the 915 (without LSD): API GL5 ./. MIL-L2105B/C/D SAE 90 (mineral oil only! No synthetic oils!!).
The 915 urgently needs a drag torque from the oil to perform the synchronization properly!! If the gear oil is too "slippery", the synchros won't work properly, especially when the 915 warmed up!
For the US market I saw several recommendations for the "Sewpco 201" in SAE90 spec. See the technical specs. This oil is also recommended to use with LSD!
Other oils can be used as well when they comapre the specs!

I cannot say ít enough: Don't use a "modern" low vicosity oil in an old 915 - also when they have been overhauled! The principle of how their synchro work won't work any more!

Regards, Thomas

[daltvater]

Originally Posted by Matt Monson

Correct. That's what I would use.

The only other thing I will add is that there's shift quality and there is wear. Some of the synthetics will feel great when the gearbox is freshly rebuilt, but they will accelerate wear, and if we bump this thread in a couple of years, it wouldn't surprise me if some of these people have needed to refresh their box because of worn synchros.

Yo Matt! I bought a bunch of Motul HD 80w90. About to pour it in but then realized that my gearbox probably isn't stock.

I just chimed in on this thread with what I know about it. Wondering if you would still suggest the same oil based on this new information?

http://forums.pelicanparts.com/porsche-911-technical-forum/1098741-915-dog-box-conversion-kit-6.html#post11564882

[Matt Monson]

No difference. Aftermarket gears still use stock synchros.

[daltvater]

Originally Posted by Matt Monson

No difference. Aftermarket gears still use stock synchros.

Matt, I put in the HD Motul 80w 90 with no lsd additive. No noticeable noise from the xf lsd and gears seem slightly smother to row through.

This was 400 track miles on the Gear 300 Motul 75w 90


Will be curious to see if wear is any less. I'll pull this current oil at the same interval of the last.

[Matt Monson]

How many oil changes since you got it?

[daltvater]

Originally Posted by Matt Monson

How many oil changes since you got it?

This was the 4th, so that is 4 since I've owned it across 1,300 track miles. The plug magnets have looked exactly the same every time.

I should hit 300-400 more track miles by mid Feb. It always exciting to check the plugs

[Matt Monson]

That’s just synchro shavings, which is what I would expect.

[oh snap]

I'm in Japan and in the same boat more or less. I have a 915 with factory LSD, 110k miles on the car, and am running Kendall for LSDs. The shifting is a bit balky, not sure if its getting worn but Im going to try a new oil. I'm not racing, just spirited drives.

Of the reasonably priced gl-5 mineral base gear oils I can find, I'm leaning towards Penngrade1 80w90 gl-5 or Motul Motylgear 75w90. I found Motul HD 85w140 but I cant find 80w90.

The Motylgear says its formulated for difficult to shift cars and it seems to get some love on Porsche sites as a swepco alternative. Motul is about 50% more expensive, but in a full oil change would only be about $35 more so not really a factor.

Any have thoughts between the two?