During the practice session for the Locost race at Oulton a nasty sounding noise started up from somewhere in my transmission. It didn't seem high-pitched enough to be gearbox but i'm not sure. My gearbox is on it's last legs, i know that, but it seemed to be coming more from the direction of the diff.

Emptying the oil out of the diff revealed it had gone black - which i took to be a sign of overheating since there shouldn't be any dirt in there. I checked it through with a magnet and there were no flakes or chunks of metal in there but the simple fact that it was black (after only a year of being in there) didn't seem good.

Changing the diff isn't really an option until the end of the season so i'm going to try stuffing some moly-slip and EP90 in there to see if that can extend its life a bit.

Does anyone have any advice?

Cheers

Rob

is your car just for race use only ?

if so i would'nt use EP90, id'e use much thinner engine oil, i know it would reduce life but in a race series with 1300 standard engines every bit counts, EP90 oil saps power, try it on a dyno, run up with normal diff oil then drop the oil and put some 0-30 engine oil in, you will be amazed how much power it release's,

diff life will be shorter though, yup molyslip, slick 50 any of those addatives would help.

All IMHO but if i was racing 1300 locosts thats what would be in my diff, and the gearbox too for that matter.

Disclaimer, diff and gearbox life WILL be reduced, power at wheels will go UP.

Does that apply to diff's of all types eg LSD or is it specific to this one only...?

Thanks guys. I've been running EP90 in the diff so far but used ATF in the gearbox. It's seemed ok but it does affect the workings of the synchromesh and so the gearchange itself is a lot rougher.

I thought about using a thinner oil in the diff too but they seem to be harder to get hold of and so i'm a bit protective of mine. Not enough though, it seems, since it's not doing so well.

After putting in a load of molyslip the diff seems to run quieter but i haven't been able to give it a proper thrashing to get it race-hot. Fingers crossed it will last for Snetterton & Mallory!

Thanks again.

Rob