transmission problem?

twice in the past 3 months or so, when I put my 89 Cherokee in gear, it did not move. Once in reverse and once in drive. It felt like it was locked up or whatever. When I gave it a little more gas, it broke loose (?) and operated normally. It made a fairly loud mechanical clank when this happened. Any ideas?

start simple - check for leaks and maybe change the tranny fluid?

Sounds like you may have a brake that isn't releasing.

One question I have is where is this mechanical clunk coming from?
That will help us in finding you a solution.

So far, I agree with Old Man. One of your brakes is siezing and not releasing. Do you use you emergency brake??

Let us know.

I am not using the emergency brake. Tlhe noise sounds like it is in the transmission.