1984 atc250r transmission Help

[dirtmaster]

My 1984 250r has 4th gear blown, 4th is there but it makes like a swirling noise but does nothing, I have to skip past it straight to 5th. My question is do I have to split the crankcase to repair or could I just remove the 2nd cover in and remove the gearset? I bought the trike and had to do a topend now that I've ridden it I found this , i do not want to split the crankcase until it needs a crank.
Any experience with this would be awesome
Thanks

[yaegerb]

if its a gear or shift fork you have to split the cases.

[dirtmaster]

So the main case, the two halves that the crank is between? Thanks Yaegerb

[atc300r]

Yes the 2 center cases have to be split. Your problem could be as simple as a worn thrush washer to a bent or broken shift fork.