With the new box I've now got in Jezebel, I figure should think a bit more about the oil that goes into it.

Up until now I've always used Mobil SAE90 GL-4 without a prob, but since this isn't exactly a standard box internally (Albins straight cuts and a Quaife) even though I have a drum of the stuff that might not be the best way to go.

Although it's not going to be worked as hard as say the box in a drag car, with hillclimbs I'm still not exactly going to be driving it normally... 3k launches, 7k in gears etc.

What's the thinking ???

Castrol Syntrax 75x/90 extreme pressure gear oil [GL5]

Recommended for Porsche , alfa, Audi, seat, Peugeot

it may be used in place of Castrol Multitrax in all High performance applications..

Fully synthetic transaxle and manual transmission fluid...

cheers

Lee

stick with the standard Mobil 90 grade

we use same in the Vintage drag car with Albins gears and all the other stuff

I have been using and recommending your 'favourite brand' of 80W90 hypoid(EP) gear oil
even though the type one tranny is not a hypoid crownwheel and pinion.

I have even tried ATF but was never as happy as with the thicker EP grades.

I am hoping to try some of the ACE air cooled oil that he makes for VW's trannys soon.

Back in 80s i had a Mitsubishi L300 wagon
and Mitsubishi put out a bulletin for people having problems changing gears with the gearbox cold..

the oil to use... ATF...

Which I did...

and it went for 15 years that i know of...

Lee

I read somewhere there was an issue with using GL5 oils with volksies as the additives affected the copper in the syncros or something like that. Article recomended to use a GL4 oil. Not sure it's got any merit or not.

Oh I found the article.

http://www.ratwell.com/technical/GearOil.html 

Interesting Reading

OK, so it at least sounds like my current GL4 isn't going to be completely wrong (I've also had hammered into me for ever to not use GL5 in volksies, but again not sure why). And yeah, that article is some interesting reading Mike.

Be interested to see how the ACE oils go in your hands Dangerous - might be worth the switch down the road.

Appreciate all the advice guys - definitely a lot happier than if I'd just gone with what the labels say.

I think I am running full synthetic in my box dave. Only did it after a full rebuild though.

jsut a thought, will the grade of oil affect the LSD in any way?

not so much with quaife.
ZF may be a different story being a clutch type.

I didn't really want to get involved, as there are more opinions and 1/2 truths around than there are products!
The question of which gear oil to use seems to be as difficult as "which engine oil"!
There are so many articles on the Net about oils. I think they mostly should be treated with CAUTION as many are hearsay & contain regurgitated info.
You should consider:
1. What the manufacturer recommended.
2. What you know about the condition of the transaxle. ie. Is it noisy/hard to change gear/older/sloppy/new etc.
3. What your mechanic/installer/rebuilder recommends or requires, eg for his guarantee.
4. What your usage/habits dictate in terms of longevity-protection-quality properties. If you want to leave it in & 'never' have to change it (as the late Manuals say you can), you couldl benefit from a top quality, dearer "Brand Name" GL-5 Full Synthetic. If you change it often (as per earlier VW Manuals), a lower spec., cheaper GL-4 mineral might do. It is a very good idea to change the oil regualry every 2 years, reagardless of milage or usage, or the fact that later manuals say you don't need to. The additives will decompose with use, time, temperature. If you do great distances, change it as per the earlier manuals distance requirments (eg. 15 000 or 20 000mi) if that comes up first. For racing you may want to change it much sooner, either for the best protection or to check for wear/damage.
5. What your usage dicates in tems of performance. The prime consideration here is viscosity characteristics. eg. For heavy loads, slow speeds, higher temperatures, a thicker oil may be better. For racing/high speeds you maust go as thin as possible. Low viscosity means less friction & more efficiency, which is why formula vees often use ATF. (I would not use ATF in a heavier or full-bodied car, or for drag racing. It isn't hypoid oil, & doesn't have any signifcant EP properties.)
I've done some testing & collection of data on a few products lately, and have changed my mind a bit. We were thinking of making a fully protected (ie heavy duty) GL-5 "racing grade" low-visc. mineral oil based trans oil. Thsi is becasue there are only GL-4's available in the thinner viscs, which are desirable for racing. We decided that better performance will be obtained from a full synthetic GL-5 than from a thinner mineral based one. The synthetic is significantly thinner at low to moderate temperatures.
If you look up oil makers' websites you can find viscosity data, look at the visc's at 40C & 100C. If anyone would like some viscosity data I could send them a table with some in due course, but i haven't finished compiling it. For short events the visc at 40C should be more relevant but for long road races or rallies, go by the 100C figure.
QPL, the maker of ACEoils, currently has a conventional mineral GL-5/GL-4 80W-90 (ACE 90) which passes ASTM D130 for Cu corrosion; and a full synthetic GL-5 75W-90 (ACE 75). We recommend the ACE90 for road/general use, and now recommend the ACE 75 for rally/hillclimb/drag use.. I always have used 80W-90 GL5 gear oil in all our VWs. All the syncros have worked perfectly, though I've noticed the difficult shifting when cold that is supposed to reduce with a synthetic. I am now progressively changing to ACE 75 (full synth.) for performance reasons for Brutus and better fuel economy for the work/shopping cars.
Sorry I'm not familiar with Quaife. LSD's with cones or clutches must use LSD oil, not normal hypoid. Conventional diffs can use LSD oil though.
SAE 90 and 80W-90 are the same as far as I know. SAE 90 mineral will also meet 80w. 80W-90 is not a multigrade in that it doesn't have viscosity modifier in it.

Appreciate all your info Brutus - I'm already trying to consider most of those angles (I think), but wanted to see what other's experience was saying.

So far in the decision mix I have:
- Quaife (diff) recommend a full synth 75W/90 GL5 for their diffs (Silkolene SilkTran). They also strongly recommend against using ATF.
- Albins (gears) don't have a definite recommendation other than synthetic GL4/5 (they promote RedLine oils)
- Berg (syncros) recommend 75W/90 synthetic.
- it's a near new box (ex JVL), not really run in enough to be sure of shifting even tho feels OK at moment
- longevity wise it definitely won't stay in more than 2 years, probably change out each year (call it paranoia on my part)
- usage is mainly hillclimbs, but also sprints and some longer road/nav events

Guess I'll do some more research and see where it leads, and then post back.

Oh and Craig - yeah, I know - each time I've seen Stan he's telling me to get up it more. I'm trying to - bit of a mind thing with me still, but with the stronger drive-train maybe it'll be 4k launches this year...