Gearbox oil?

[Southern75]

What sort of oil do the sud racer types use in their gearboxes?

I need to do a change and haven't really looked into it other than using run of the mill standard type mineral oils of the appropriate spec's

Any suggestions?

[colcol]

I used to use Penrite full synthetic 80-90, the gearbox use to crunch less when it was cold, and when coming off the track you could always put it in reverse and back up into the pit bay, and it is easily available at Repco, no special orders or that kind of thing, it made quite a noticeable difference compared to mineral oil 80-90, Colin.

[meizhak]

I have a sud box with lsd and are using castrol syntrax 75/90 full synthetic, freekin expensive but really good gear shift.

[colcol]

Some V-8 supercar teams use that oil, Castrol Syntrax, and it depends to if you are running a LSD or not, Colin.

[meizhak]

colin, really good oil but over $100 for a oil change

[colcol]

Its that old compromise, do i put Penrite synthetic in at half the price of Castrol Syntrax, and change it twice as much or do i put the potentially better Castrol Syntrax in and change it half as much, put the cheapest oil in that will do the job and change it more often, then when you drain it, you can see how dirty your oil is and how worn your gearbox is, Colin.

[hammer]

I use the Castrol Syntrax 75/90 in the Giulietta's transaxle and find it to be good stuff. Am about to pull the box out after this weekend's sprint so will be hit in the back pocket yet again, but it seems worth it to safeguard an expensive set of cogs.

Cheers,

Brent

[Evan Bottcher]

How do you tell if a gearbox oil is good? (serious question)

[colcol]

If your gearbox oil has gone black or metalic then it has been contaminated with rubbish, thats why it is important to drain your gearbox oil on a regular basis to keep a check on wear, my 33 is off the road at the moment and i recently drained the gearbox oil and it was as clean as the day i put it in, so i filtered it and it will go back in, good question Evan!, Colin.

[Evan Bottcher]

My question was slightly different.  How do you tell if a particular brand / grade of gearbox oil is good? 

I hear a lot of people give advice, always wondered how you would tell the difference?  If it's just the quality of the gearshift, it seems to me a better shift might be provided by a lighter gear oil but sacrifice wear on the gears themselves?

[colcol]

When we used to run the 33 on the track in the olden days, and you had mineral oil, the gears would crunch, the shift would be difficult, you couldn't select reverse to back up in the pits, with Penrite Synthetic oil, you have none of these problems, there may be better oils to suit your particular needs, but Penrite was the oil for me, and it didn't cost the earth, so you could change on a regular basis, Colin.

[Southern75]

Definitely some interesting discussions ...

I'm just using my old box but as the car hasn't been running for a while i need to change the oil before if start getting too enthusiastic ...

I think I'll try the Penrite that being the case ... but  Castrol is always up there with my choice of oils... Penrite too for that Matter.

Hey i know its a little off topic ... but i have heard Castrol Oils stuff up the engines in the new alfas 156 and onwards ... is it just because people are strtching them to 15k service intervals or is a a lot of BS?

[colcol]

Castrol gearbox oils may be as good as Penrite, but i have never seen them for sale, with Penrite synthetic gearbox oils, they are available off the shelf at Repco for a reasonable price, as for the Castrol oils stuffing up 156 engines, i was told by an engine builder years before i got my 156, that the best oil for low wear on race engines was Castrol fully synthetic 10-60, but i am not an engine builder so i don't know how true this is, if you are stretching your engine oil to 15,000 ks, you are an idiot, try using a cheaper oil, with the same specs and change it more often, Colin.

[Southern75]

Well in my 147 i use castrol edge fully synthetic 0W-40 and change it at 5k. (It's a diesel btw)

Yes it may cost $70 a bottle but its cheaper than a new engine.

I don't like the idea of 10K changes.

Hell my 75 usually gets its oil changed at 3k -4k.

Am a bit slack on gearboxes though 

[colcol]

Hey southern, make sure the oil you use in your 147 has a diesel rating, as petrol and diesel and LPG oils are all different, although sometimes they will interchange, but i don't know what the code is for diesels, but i am sure its on the web, oil changes distances and times, how longs a bit of string, engines used in the city for short trips and never warmed up, lots of crankcase dilution, change it more often, engines used for long drives and on freeways, when the oil is warmed up and the contaminants are burnt off, change less frequent, i changed the oil in my 156 JTS gearbox after 80,000 k, was as clean as the day it went in, no discoloring, filtered it and will keep it for a rainy day, gearbox oil in 33, always dirty after about 5 years, fling it and put some Penrite synthetic in, Colin.