Guys, this is unrelated to hot rods but would appreciate the help.

A little history: 91 Jeep Wrangler 2.5 4cyl 5 speed manual
A lot of miles. Just hit 170,000.

I'm just not sure where to start and if I take her to a shop...well that'll delay the 36 quite a bit longer. So I'd like to try to do this myself.

This ole girl hasnt been abused....oil changed often...no oil leaks....no blow by. But the engine is starting to show its age with mileage. Tick tick tick...or is that a light knock. For a very long time now, 3 years, I have had the indicator of a clutch problem. If I don't give a decent hesitation between shifts it will have a slight grind when going into the next gear. I usually can drive it without a single grinding gear on a up shift. On a down shift it always grinds no matter how long I engage the clutch. Same old story....I've been very easy on her to make her last. She's probably due for some serious work.

Tonights scenario. I was on the way home after work....at about 10 miles I had to stop to make a turn....upshift from 1rst to 2nd....smooth....upshift from 2nd to 3rd....smooth...until about 1600 RPM's then it has a moderate vibration....upshift from 3rd to 4rth.....again at around 1600 Rpms it vibrates all the way up to 2500 when I shift into 5th.....and again at 1600 a vibration.
I can duplicate this each and every time and the transition from 1rst to 2nd and 2nd to 3rd is fine. When it is vibrating the most .....if I engage the clutch the vibration is gone....indicating to me that the transmission and u-joints would be fine. When I rev the motor to 3000 rpms I feel no noticable vibration in the engine. I know it probably wants a rebuild but I just dont thing its the engine.

I know nothing about manual transmissions. Had at least 4 350 tubos, a 400 turbo, and 2 700r4's that I did a shadetree rebuild on. But I know nothing about clutches. Could my clutch be missing a chunk out of it which would thow it off balance? And if so....wouldnt it vibrate in 1rst and 2nd also?

Moderators. I hope this is where it should be. If not I apologize.

Thanks. Any help will be appreciated.

Dave G