Gearbox oil change made things worse.

[sierragls]

Can anyone explain this. I changed the oil in my gearbox as occasionally it would pop out of reverse and whines a little when reversing, but now it pops out of reverse almost everytime now and it's a little stiffer to get into 1st when changing down. I know the eventual prognosis is a new gearbox, but most on here have seen improvements when they had done an oil change.

I used halfords 80/90 oil.

[Rmachines]

Use Castrol syntrans/syntrax fully synthetc it the gold bottle.   

[Leroy]

I did the same when the synchromesh was going so it was crunching into 2nd gear, put new gearbox oil in and was worse so ended up getting a new gearbox.