R380 jumping out of 5th gear

[DEF95]

Hello everyone
I have 1995 defender and when I was driving home today if jump out of 5th gear i pushed the clutch in put it back in 5th it stayed there for about another 10 km then it jumped out again but this time when I went to put it back in ,it when in for a few seconds then jumped straight back out I tried a couple of more times same thing kept happening so I left it in 4th and drove home. I was wondering what you think could be wrong with it.
Thanks

[landy]

Sounds like the 5th gear bulking rings/teeth are worn.
Does it jump out as you back off the throttle or on over run?

[DEF95]

Thanks for the reply Landy
It 1st jumped out when I was going up a small hill. All the other times it was pretty flat and I was just changing from 4th to 5th like normal