I drive a 04 Musso 4x4 Sport and experienced difficulty when selecting 1st and reverse gears. By process of elimination I had the cluth pedal freeplay removed, problem persisted. Then I replaced the master cylinder and bled the system, problem persisted. Then I replaced the slave cylinder and bled the system hoping that my problems will now be something of the past, but my problem persists. Does anyone have further suggestions?

PROBLEM SOLVED !!!!
I also explained the above problem on another forum www.ssangyongclub.uk and the solution offered was to check the gearbox oil. The oil that is supposed to be in the gearbox is automatic transmission oil and not standard gear oil for manual transmission. I drained the oil (which happened to be standard gear oil) and replaced it with Dexron 2 , result "as good as new"!

Subsequent to this I traded this vehicle for another make and model. See my question elsewhere!

Changing the Oils in your vehicles; gear box, transfer case (low range box) and diffs is always a good exercise.

You'll need to buy a minimum of 10 litres to do all (an SFA Hilux requires 11.5ltrs) but the resultant smooth gear shifts and quiet operation is well worth the exercise.

A good buddy of mine was having the same issue with reverse gear and it all came right with a change of oil as you suggested.