anyone got any ideas .... been on the 4x4 track at robin hoods bay today , up and down hills , through deepwater ect ect then the clutch felt like it was slipping , so when i drove out it was really struggling to get up a hill , got towed to the top of the bank dropping down to stokesley, took the motor off tow and drove it down and it was fine drove it all the way home , clutch seems fine now , any ideas ?????