Interesting..... my '91 I just sold did that same thing before I put a new clutch kit into it...it would also pop out of first gear. After the complete clutch rebuild all symptoms went away.
On my current 86 4Runner I have the opposite problem two of you guys have....I get noise when the clutch IS NOT depressed <img src="/forums/images/graemlins/confused.gif" alt="" />....push in the clutch and all is quiet.

Good Luck,
shaggy <img src="/forums/images/graemlins/smile.gif" alt="" />