If it's not Swepco --, what is best oil for gearbox? Options

[neil30076]

Manual recommends SAE90 - what brand / weight does anyone recommend for here in southern california ? Most parts places have SAE 75W/90 or 85W/90 - Not sure i want to go with Swepco - but could be convinced - road use only !
Yes, I did search, didn't find a firm conclusion.

[r_towle]

GL5 rated...pick a dino oil.

Rich

[SirAndy]

Swepco 201 (IMG:style_emoticons/default/thumb3d.gif)

[Cap'n Krusty]

ANY good dino GL-5 will be fine, 80/90 or whatever is close to that. NO GL-4, no mixtures, AND NO moly based additives. EVER. Takes about 5-5.5 pints, and it generally comes in 1 qt containers. Remove the fill plug first! Might not want to drain it all out and find you can't refill it ............. BTW, gear oil doesn't "wear out", so changing it is required only to observe what's stuck to the magnet on the drain plug, or because you have a problem and need to disassemble the tranny.

The Cap'n

[SGB]

WHUT HE SAID ^.....


Oh, and if you can't get the plug out, at least top it up. Usuallly some gets away. And Mobil 1 synth will NOT work. It's too slippery for the synchros to work.

[iamchappy]

I've had real good luck running AMZOIL in my 901 boxes for the past 20 years.
My boxes shift great!

[0396]

Funny, I met up with the local Swepco rep last weekend for a case of 502 oil additive...and when we spoke of my 915 box. He mentioned that many are running 90/140 or 80/140 or some thing like that.....mentioned that it worked better than the 80/90. My old Porsche Master Tech and I are going in on a case of this stuff for my 915 and 901...oh forgot we are going with the 202 /212 ...the one with moly in it.

[0396]

ANY good dino GL-5 will be fine, 80/90 or whatever is close to that. NO GL-4, no mixtures, AND NO moly based additives. EVER. Takes about 5-5.5 pints, and it generally comes in 1 qt containers. Remove the fill plug first! Might not want to drain it all out and find you can't refill it ............. BTW, gear oil doesn't "wear out", so changing it is required only to observe what's stuck to the magnet on the drain plug, or because you have a problem and need to disassemble the tranny.

The Cap'n

Why no moly? or is it because of the limited slip?

[PRS914-6]

Well, I have to say that I use Mobil 1 75-90w with great success despite the warnings against it from everyone and their brother including Bruce Anderson. My tranny shifts like butter with never a grind. You'd never know it was a 915. Now everyone and their brother, sister, great aunt and two year old son and pet dog will tell you that Mobil 1 is too slippery but personally I have never had a problem, only much better shifting. I used the stuff in my 901 then the 915 as well as my 911 with a 915 and all shifted MUCH better. They were all fresh trannies though. These trannies have different syncro systems than modern day transmissions and that is why the warning about avoiding synthetic.

If I had an old tired tranny I would probably stick to dino oil. If the tranny was fresh, I wouldn't hesitate to use synthetic in a street car....let me repeat....a street car because when street shifting you are typically shifting pretty slow compared to racing and my experience has been all positive with no negatives.

You will find that people will swear by all kinds of oils mainly because that's what they have had good luck with and I'm no different. I like Mobil 1.....Your mileage may vary and the sky might fall if you use it.

While gear oil isn't exposed to contaminates from engines like motor oil it can suffer from heat break down. Our cars have hot air cooled engines that blow heat around our trannies and the heat exchangers don't help much. Synthetics have a much higher tolerance to heat than dino oils.

I don't want to start an oil war so I'll just say try it at your own risk and expect that everyone will discourage its use..... (IMG:style_emoticons/default/smile.gif)

[Cap'n Krusty]

ANY good dino GL-5 will be fine, 80/90 or whatever is close to that. NO GL-4, no mixtures, AND NO moly based additives. EVER. Takes about 5-5.5 pints, and it generally comes in 1 qt containers. Remove the fill plug first! Might not want to drain it all out and find you can't refill it ............. BTW, gear oil doesn't "wear out", so changing it is required only to observe what's stuck to the magnet on the drain plug, or because you have a problem and need to disassemble the tranny.

The Cap'n

Why no moly? or is it because of the limited slip?

What limited slip?

Moly makes everything slippery, and the Porsche style synchros work by friction. Get the picture? And once the moly is in there, it doesn't really come out. It's a "feature"! Probably works fine in VWs, Chevys, and G50 trannies.

The Cap'n

[Cap'n Krusty]

Funny, I met up with the local Swepco rep last weekend for a case of 502 oil additive...and when we spoke of my 915 box. He mentioned that many are running 90/140 or 80/140 or some thing like that.....mentioned that it worked better than the 80/90. My old Porsche Master Tech and I are going in on a case of this stuff for my 915 and 901...oh forgot we are going with the 202 /212 ...the one with moly in it.

He can't be that old, because we went through gear oils in Porsche school in the '70s, including all the reasons for using GL5 instead of GL4, and why you don't want moly in your Porsche gearbox. Maybe not that much of a "master tech", either. What ever that is ...................... Might wanna find a new one. As for the Swepco rep, he's a freakin' SALESMAN, and his lips were moving!

The Cap'n, Swepco free since 1964

[craig downs]

I put Royal Purple gear oil in my 901 and its been working very good.

[Downunderman]

I have found Motul FF LSD to be excellent if you want to use a synthetic, http://www.motul.co.jp/eg/product_line_up/...box/gear13.html , although its not cheap.

[Chris Hamilton]

He can't be that old, because we went through gear oils in Porsche school in the '70s, including all the reasons for using GL5 instead of GL4, and why you don't want moly in your Porsche gearbox. Maybe not that much of a "master tech", either. What ever that is ...................... Might wanna find a new one. As for the Swepco rep, he's a freakin' SALESMAN, and his lips were moving!

The Cap'n, Swepco free since 1964

I made the mistake of putting swepco in my gearbox once. Never got it to shift again. I've just been driving around in 2nd for 8 months now.

edit: seriously though, I've got it in all my 901 boxes and it's good stuff

[CliffBraun]

He can't be that old, because we went through gear oils in Porsche school in the '70s, including all the reasons for using GL5 instead of GL4, and why you don't want moly in your Porsche gearbox. Maybe not that much of a "master tech", either. What ever that is ...................... Might wanna find a new one. As for the Swepco rep, he's a freakin' SALESMAN, and his lips were moving!

The Cap'n, Swepco free since 1964

I made the mistake of putting swepco in my gearbox once. Never got it to shift again. I've just been driving around in 2nd for 8 months now.

edit: seriously though, I've got it in all my 901 boxes and it's good stuff

I agree, none of the gearboxes I've worked on, including the one I drive around, work anymore because of swepco. Sorry, that was they all work beautifully, so easy to get the two confused.

[abbott295]

Would you have to have a working car to know how your transmission shifts with whatever oil?

Shift free for two years!

[ArtechnikA]

What limited slip?

Moly makes everything slippery, and the Porsche style synchros work by friction. Get the picture? And once the moly is in there, it doesn't really come out. It's a "feature"! Probably works fine in VWs, Chevys, and G50 trannies.

There are of course Porsche 901/911 and 915's with limited slips - I know you know this.

Interestingly, the recommended (by Steve Weiner...) gear oil for Porsche/ZF LSD's is moly-bearing Swepco 203. I have used 203 in my non-LSD Type 911 transmission and it shifted (i.e. synchronised) no worse than before (which was not great, especially 2nd...). It has a grey but not black cast to it so my impression is that there isn't -much- moly in it...

I've used some sort of moly disulphide additive in most of my Porsche boxes, and all of the newer cars, with no discernable ill effect. I'm sure a part of it comes to technique. I once drove a car a couple months with no clutch when money was really tight. If you can shift without needing the synchronisers, you probably won't notice if they're a little less than optimally efficient.

So I don't recommend moly in a Porsche trans/diff either -- but I use it. The Captain is right - the good news is, it hangs on for a long time. The bad news is, it hangs on for a long time... So don't be thinking you can just drain it out if you don't like it.

If for some reason I were determined not to use Swepco in a Porsche box, I'd probably use Royal Purple's 90-140. The viscosity is right and it is a GL-5 lubricant. I would not use the 75-140 unless I were in someplace seriously cold.

[Cap'n Krusty]

I didn't mean to imply Swepco gear oils are bad, just expensive and unnecessary. The most important thing is to use the CORRECT product for the application. And, of course, remaining free of the cult. I DO know there are a FEW 901s around with LSDs, but the original question led me to conclude the person asking may have thought they all came so equipped. The Cap'n

[neil30076]

ANY good dino GL-5 will be fine, 80/90 or whatever is close to that. NO GL-4, no mixtures, AND NO moly based additives. EVER. Takes about 5-5.5 pints, and it generally comes in 1 qt containers. Remove the fill plug first! Might not want to drain it all out and find you can't refill it ............. BTW, gear oil doesn't "wear out", so changing it is required only to observe what's stuck to the magnet on the drain plug, or because you have a problem and need to disassemble the tranny.

The Cap'n

Thanks cap'n, and all.
Engine and box are out, all drained , ready to refill and reinstall - (IMG:style_emoticons/default/driving.gif) is next!

[Drums66]

AMZOIL (IMG:style_emoticons/default/idea.gif)

(IMG:style_emoticons/default/popcorn[1].gif)