Hi guys I'm putting a new box in my car and refitting the diff etc can someone simply tell me what oil and how much to put in it? Also diff oil. I know to fill the diff until it flows out of the top plug hole (about 1.7 litres I think)
I'm only asking because I know that enthusiasts prefer to run different oil to manufacturers recommendations etc and I want optimum performance and lubrication. Thanks guys

Well I was told to use high grade ATF in the gearbox but I've always run 10W40 and it's been fine. Normally I get mineral oil because it's slightly cheaper. Same as the diff, make sure it's horizontal and fill it up until it starts pouring out the side plug

I use normal diff oil in the diff, and same as speedy, 10W40 in the box itself.

Ok cheers. How much box oil do I need to buy? And what type of viscosity diff oil do you recommend?

Can't remember diff oil, went to halfords and it was what their system quoted. Gearbox I'd say 3 litres (guessing). I bought an oil change (5 litre) can and used that. The spare stuff I kept for the engine.

I think gearbox is 3 or 4 litres, diff is 1.7 litres I think. You'll need 80w90 or something close to that. Rather than going to halfords, go to GSF if there's one near you as they sell 80W90 at £15 for 4 litres.

Also go on ebay and get yourself a haynes manual, plenty of info like this in there (although it doesn't note using 10w40 in the gearbox).

pretty sure it says in the handbook too

is 10w40 fine for the box? I've just gone and bourght 3L of expensive ATF stuff

I've had a really good chat with Mac re box oil as the green book changes over time. Orig ATF, from memory, was found to be slightly noisy so changed to 10/40. However, that gives a notchy feel to the box. Horses for courses, I know which I'd prefer

Originally the M45R was specified for use with 10w40 engine oil with an alternative of ATF for Nordic markets
(as engine oil at low temperatures was found to give "agricultural" gear change quality.)

In service however 10w40 resulted in notchy gear shifting even at "summer" temperatures so the recommendation
was changed to ATF for all markets. Ho hum - this cured the shift quality complaints but introduced moans about
gear noise (more so with the alloy cased M47R/R2).

You takes yer choice notchy or noisy - but either oil is fine lubrication wise with ATF giving the synchros a slightly
easier life. In real life, if a box is in good order, neither the "notchy" nor "noise" was real problem.

Macs choice - engine oil (but I tend to DDC anyway so synchro stick isn't an issue for me)

Mac

Thankyou very much