pg1 gearbox

hi all have an 02 1.8 freelander with a small prob, she keeps jumping out of reverse gear when you put a bit bo load on the gearbox eg.. turning on full lock or trying to push her up a small hill in reverse, it will jump out of gear and grind all, other gears are fine, is there any ajustment on the box or is it a rebuld or new box

just need rev idler i would think,but means box out

i dont mind pulling the box out the clutch could do with changing soon so was going to do the box and clutch together

if just reverse gear worth looking at if other gears are poor another box perhaps ,idle will either be worn on edges or some part of linkage wont be pushing it far enough into mesh,box would need sealing with silcone sealant rtv after

ye it feels like its not going fully into gear,

time to get the tools out me thinks