Can I adjust downshift(kickdown)?

My 1997 jimmy will not downshift at highway speeds unless I put it to the boards and even then it only downshifts to 2800 rpms and is touchy as it graps the lower gear right away. The pedal will travel 9/10 of it travel ability before it kicks down or does anything. Is there anyway to adjust this to kickdown at less then to the boards?

You could adjust aclutch back when they were 100% mecanical; but I don't THINK you can adjust a more modern hydrolic clutch...

Has it always done this, or did it just start?
How many miles do you have on that clutch?

it could just be worn out, and in need of replacement.