I'm assuming this is about auto gearboxes, by the amounts of oil mentioned. So, excuse me if I'm wrong. The factory handbook says, for the Mk1 auto Disco: Ambient temperature should be 68F or 20C. Vehicle on the level. Gearbox cold. Start the engine. With both brakes applied, go from P to D1 and back to P. With the engine still running, check the gearbox dipstick levels. From the low mark to the full mark is 0.25 litre top-up.
I did this, and checked the next day with the engine off, and gearbox cold, and the fluid was one and a half inches above the dipstick full mark. Did the procedure as above, and it was spot on the full mark. The levels are very temperature dependent, and can't be done accurately if the box is warm.
I hope you got a few hundred quid off for an auto-box with black oil in it. A sign of severe mis-use, or even the wrong oil! Just because the manual box uses the same oil as the auto, some idiot garage hands think that means EP90 will do in either. My (95) Disco Mk1 auto has done 125k, the oil is still almost invisible pink, after topping up at 60k, and changes up and down as per the handbook.
The box holds almost 10litres, (17+ pints) but you can't get it all out, as some stays in the torque converter.
I thought the later Disco's auto-box was sealed for life, with no dipstick.
Don't see how excess oil can get "out" unless a seal gets blown-then you really are in the s***t, the normal pressures inside are high, anyway,so there won't be an overflow hole!
Hope this clarifies the levels queries.
