On the American market Daewoos' (GC25E-3) I've been very successful using straight hydraulic fluid. Change the fluid regularly why should there be a problem?

Most 10W agricultural transmission oils will be ok. Tractors mostly have oil immersed multi disc brakes and all these oils have the anti squeal and glazing additives.

thanks but what is the specs on the john deer 10w oil so that i can use the equivalant, the oil was replaced by someone else some time back and i inherited this problem, it seems they used 80w90, which is far too thick, the local agents hasnt got got a clue as the truck was previously maintained and serviced by them.

danny dont use 10w engine oil for fooks sake.

It contains things that will eventually glaze the brake system. The first thing you might notice is squealing brakes.

Use the proper John Deer 10w oil, this amongst other ingredients contains anti-glazing agents

The oil is thick because it should be changed after a while, I think its 1000 hours not sure exactly.

Hi Arnie,
It should be 10W engine oil.