yes that is true that it could be the gearbox however its fine if i go to 3rd then back to 4th. i have heard the splines in the axel sometimes can spin even in nutral and cause this issue. its just finding the time to check it. plus i have seriously hurt my back so i cant really do it at the moment. but the info is good guys. ill get my mate to pull it out and then ill crack it open and have a look but to be on the safe side im getting 4 new tyres 4 new wheel bearings and new g/b oil and diff oil.

ill try this and if it is no better ill have to see what else it could be.