JCB 3CX Will not move forward?

My 86 3cx 2wd will work in reverse fine. When I need forward it will select it ok when cold but once warm it needs 2/3 movements of selector back and forward to get it. Also when it meets an incline it looses a lot of power. I've noticed an oil drip from between engine/torque-con and it seems to be milky?! Is the trans oil cooler gone?
Also my machine no. is 318*** black cab, can any one tell me what project no. this is and where I could get an operator/service manual?

Thanks for any help.