Best oil for the 915 gearbox ?

[Litle brother]

Which oil to use in a 1978 915 gearbox?

I used Porsche spec. gear oil in my 915 the first year of owning it, from 2012 to 2013.
But because the gearbox had some minor syncro issues between 2 and 3 gear I changed to Swepco 201, which I have used since.
I found a great improvement using the latter one, also together with my newly built 283PS, 343Nm 3.2 SS engine.
But I still have a question to the forum here: what is the best all purpose oil for my gearbox?
I like to run the car hard but it never sees the track.

Regards
Eskild

[DanielDudley]

201 is what the racers use, because it is so good at protecting gears and the ring and pinion.

Our host also sells the Kendal gear oil, which many like to use and say makes the shifting easier. It is a conventionally refined oil of high quality.

If what you are using works for you and you like it, you cannot buy a higher quality oil that will protect better.

[Matt Monson]

You won't need to change your gear oil for another couple years. Worry about it then.

[OldSpool87]

Matt-

Do you know anything about BG gear oil?

Thanks

[Matt Monson]

Originally Posted by OldSpool87

Matt-

Do you know anything about BG gear oil?

Thanks

Nope. I've used some of their other products but know nothing about their oils.

[DRACO A5OG]

OP, best oil alternative is you the user, try double clutching to lengthen the life of the ready to fail synchro bands & sliders. They are simply not biting as they use to due to wear and tear.

Sorry to write, your gear box is trying to give you a warning that is time to rebuild the gear box Synchro Bands 1-2 & 3-4 and Sliders. If you wait too long then your dogteeth 1-4 may need changing. You will be doing this sooner or later and with your new engine, I am surprised your mechanic did not recommend this.

[Bob Kontak]

Originally Posted by Matt Monson

You won't need to change your gear oil for another couple years. Worry about it then.

I used 201 for years until it needed rebuilt. It's red.

210 is green and stinks.

How is that for adding value.

If Matt says 201 is ok, use that and consider the 210 or the Kendall next go around. Make sure you read up on which Kendall to use. They may treat synchros a bit better than the 201 but I cannot speak from experience, just what I read here.

[Ian Comerford]

Motel 75/90 Technosynthese. I put this in mine after 201 and found it shifter better, it is recommended for hard to shift gearboxes

[fizeus]

Originally Posted by Ian Comerford

Motel 75/90 Technosynthese. I put this in mine after 201 and found it shifter better, it is recommended for hard to shift gearboxes

Did you mean Motul? If yes i think it's 80w90.

[Ian Comerford]

Yes, sorry Motul

[smarens]

Peter Zimmerman (who literally wrote the book on 915's) stated to me "Recommended oil is Kendall 80w/90 Dino NS-MP Hypoid GL-5. Please do not use synthetic oil of any brand."

-who am I to question him, that is what I will be using when I get my car together

[fizeus]

Motul Gearbox fully meets 915 specs like sayd by our member Peter.
It's an 80w90 dino oil reinforced with molibdenum.
While I agree with swepco to be a good oil for our trans i have to say that Motul is equal or better in my case. .... as said tons of times.... it's a matter of taste.
Also, in my country, italy, it's easier to find and this mean that i can change it often!

Here is a reference: https://www.motul.com/it/en/products/gearbox-80w90

[HarryD]

Originally Posted by Bob Kontak

I used 201 for years until it needed rebuilt. It's red.

210 is green and stinks.

How is that for adding value.

If Matt says 201 is ok, use that and consider the 210 or the Kendall next go around. Make sure you read up on which Kendall to use. They may treat synchros a bit better than the 201 but I cannot speak from experience, just what I read here.

Bob. Are you sure it is 201? My SWEPCO 201 is Smurf blue.

[Matt Monson]

Originally Posted by HarryD

Bob. Are you sure it is 201? My SWEPCO 201 is Smurf blue.

He flip flopped them. 210 is red.

203 has moly for those considering that Motul oil. Shifts a little better cold but too slippery for use with an lsd.

[adias]

I switched from Swepco 201 to Swepco 203 (containing Molly) and the transmission is quieter and I feel that its losses are lower (car glides as compared to before).

[3rd_gear_Ted]

What ever oil you choose for your 915 is a compromise; the ring gear wants slippery, the synchros don't like slippery.

For my track only use 915, I want the ease of shifting during racing along with the the optimal operating condition for the LSD and consider the ring gear a wear item to be replaced within a couple years anyway.

For that reason, Redline was my sentimental choice, same oil as specified for my "back in the day" T-10 Muncie gearbox on a Chevy Z-28 I once street raced with that had over 400+ HP.

[Claus Poulsen]

Hi Eskild
I see you are in Norway. I tried to find Kendall in Scandinavia but couldn't find it.
I dont track my SC, so to try something else, I dumped my Swepco 201 and put in cheap mineral Hypoid GL-5 from "Biltema" which has properties close to Kendall. Significant shifting improvement. Easier to get into first and second which was difficult at times before. I will drive it with this oil one season and then go for new syncros. They are worn and no oil will fix that. See how the upper half of the ring is darker/shiny? Photo is taken through the fork plate hole. And yes, 201 is blue and I may switch back when my syncs are new and have grip again.

['76 911S 3.0]

Swepco Transmission Fluid Question

Lots of info in this thread

[Litle brother]

Thanks for the answers


Sent from my iPad using Tapatalk

[BE911SC]

Originally Posted by smarens

Peter Zimmerman (who literally wrote the book on 915's) stated to me "Recommended oil is Kendall 80w/90 Dino NS-MP Hypoid GL-5. Please do not use synthetic oil of any brand."

-who am I to question him, that is what I will be using when I get my car together

John Walker also uses Kendall. He and Pete Z should be all the recommendation you need.