gearbox trouble

Recently my standard Jimny developed trouble shifting into reverse. It would grind as I put it in reverse even though the clutch was fully compressed. I would put it in first and try again and it usually shifts ok. I noticed that it doesn't shift all that smoothly through 1st to 5th. I must be used to it. Do you think it is a gearbox or linkage issue. Do any other Suzuki's use the same gearbox as my 2004 Jimny?

Sounds similar to problem with my 2004. Required new bearings, some of which were only scalable from Suzuki. Local gearbox repairer dismantled it and told me what I needed. Hope this helps.