92 4x4 problem

[Phil79886]

I have a 1992 Toyota SR5 V-6 5 speed 4x4 4runner. I have somewhat of a problem, the 4x4 will not engage most of the time, sometimes at random it will engage when shifted of course. I just checked the Tcase and it was indeed about a quart low. I just had the tranny replaced and a new clutch. It worked after that for awhile. Then it started giving me problems. It started working again, then I had the master and slave clutch pistons changed and now its a no go. Any ideas? Sorry if i am hard to understand english was not my first langauge (moms idea) hahaa well thanks guys