Intermittent hard shift AX-15 (long)

So this seems to be a common issue but this is the first time I have run into it. My 90 with an 4.0/ AX-15 has never had any trouble shifting. Yesterday I drove it to NW Fest which is a little further than I drive it normally (150 Freeway miles) When I got there I noticed that I could not get the Jeep into reverse easily, Also shifting into other gears was "hard" (engine running at jeep stationary ) So most logical thing to do was to look at the hydraulic fluid for the clutch. (it was lowish but not low enough to admit any air). The thing that pointed away from this is that once in gear, the clutch engages at the same pedal position that it always has.
So when I got home I pulled the fill plug on the tranny and nasty looking fluid came out (overfilled?) Once the transmission cooled down it seemed to shift fine.

For giggles I bled the slave cylinder. I jumped online and ordered some Redline MT 90
which I will put in next.

Question are what the heck could this be? Seems to happen when the transmission is hot only, I am wondering if I am having a problem with the clutch disc sticking on the input shaft (that is what it feels like) Is it possible when transmission fluid gets old that it is less functional at high temps? I am wondering if a previous owner overfilled the tranny from the shifter hole but can't imagine that it would cause this problem.

Will post when I have redone the fluid with results but any ideas welcome. Have read most of the posts recommending Redline.

IF I remember correctly, the reverse gear doesn't have a synchro. So sometimes it will resist going into gear. Try bumping it in first (ie: putting it into first gear and letting the clutch out a little so it will spin the tranny a little bit) then going to reverse.

MY AX-5 does that all the time.

Recently, my clutch master cylinder took a dump. The shifting got progressively more difficult as the cylinder would leak while it was on its way out. It finally went on thursday (fluid all over the carpet and fuse box). I replaced it, and my shifting problems are gone now. I bought the Wagner one. Its cast iron rather then aluminum. Retails for about $70.

Luckily, the clutch/slave cylinder were replaced on mine shortly before I bought it.

I have had the same issue recently. Once the engine/tranny warm up, the shifts felt sloppy, esp from stop... Really sucks for 20 min of bumper to bumper traffic every day... but I digress.... DONT jump right in and buy a new master cylinder.. I did and it did nothing for my problems. I would first recomend buying a new thing of brake/clutch fluid and completely bleeding out the system with new fluid, like a freshly open thing of it. How long has the bottle of fluid you now have been open in your rig or garage? I know that a few times now since I had my issue my fluid was lowish so i topped it off with new fluid rahter than the older stuff I had, and after a few top offs it has been much better. I just havent had the time to get a full bleed. I went out and bought the new master cylinder with the EXACT same issues, and when I installed it... bled fluid through... felt confident... and same problem. I am unsure what kind I got but it was the expensive one at autozone, cast iron.. may be the Wagner one... but I gotta say.. the cap sucks, doesnt like to thread on nicely.

Long story short... completely bleed the system with a new thing of fluid (not that stuff off your shelf). There may be moisture in the fluid. I know just topping it off w/ new fluid has helped a TON for mine. Its fine through traffic now and only feels weak once in a while, but still goes into gear fine.