Shifting issues -- clutch?
 

I've got a '91 XJ, 5-speed, 4.0, with 217k on it. Seems to work fine when the weather is warm, but last winter it shifted hard when it was cold. Once it got warm -- 20 minutes of driving or so -- it shifted much easier. When summer came around, it was fine again. Now that cold weather is back, it's acting funny. It started with some odd chattering sound that I only got in 3rd gear, usually only when I had downshifted into third after having been in 4th, and only when the clutch was engaged (pedal up). When I pushed the clutch pedal in, it went away. No problems or noises with other gears. Went to drive it on Wednesday evening (a little colder than it has been), and it was much worse, and I was having trouble with other gears, as well. It was very difficult to get it into second when upshifting (it was grinding, even with the clutch all the way in), and there was worse chatter in both first and third. First in particular was a little scary when I took off from a stop light, before I had completely let the clutch pedal up.

When I shift through the gears with the engine off, it shifts fine. I wouldn't say "smooth," but reasonably easy, with no real differences between gears. If I am sitting with the engine running and clutch released (pedal down), then start to engage the pedal (lift the pedal slightly) without giving it gas, the jeep will start creeping forward, as it should, but it's not smooth -- it jerks forward slightly every half-second or so, like the clutch may be catching intermittently. Same thing happens when in reverse. The fluid level is fine, and I haven't noticed any leaks.

I've searched around the forum some, and seen people with similar problems that turned out to be incorrect or bad fluid in the transmission, but this seems more clutch related. Any help?

Also -- how do I know whether I've got the internal or external slave cylinder (it is snowing like hell out there, so I don't feel like crawling around right now).

Sounds like you may have a slave cylinder issue, but with 217k on the clock it may be time fore a whole new clutch. If you have the problematic internal slave/throw out bearing combo you gotta pull the transmission, so do the whole clutch at the same time. If you have the external slave it will be a lot easier and cheaper to do the slave cylinder.

THanks for the input. My understanding is that it should be the internal type. I have owned it for 2 years (only put 7,000 miles on during that time since I use it mostly for hunting/camping/fishing or for around town when it's really snowy). Don't know about the previous owner, but the owner before him tracked every dime he spent on it in a mileage log, and at 136,000 miles (in 2002), he shelled out $615 for "Hyd. Cyl. for clutch." Then in 2006, at 171k, the book says "oil changed, clutch fixed" for $317. Hard to know what that means, but I'm sure the clutch has been replaced at least once, right..?

I do some of the maintenance and repairs on my vehicles (have diagnosed and replaced several sensors and other parts on this thing), but have never done a clutch. I'm not sure I have the tools (transmission jack, impact wrench) or time to do the job. With that many miles and some engine noise, I don't know how much I want to sink into this thing to have someone else do it. If I could get by with it for another 6 mos., I'd be in a better position to buy a replacement or shell out for a new clutch. If I could get 500-1000 more miles out of it in that time, that would be good enough. Seems like it got much worse pretty quickly, so not sure I can make it that long...?

Fluid level?
 

One other thing -- the master cylinder has the non-transparent type reservoir. Where should the fluid level be on this?

I had the same problem you are experiencing, with my 96 Cherokee, and it turned out to be a worn out clutch. I kept driving it, and it wore out the second and third gear syncros, so I now have that AX15 transmission in pieces in my living room that Im trying to get back together with new syncros. Clutch kits can be had pretty cheap, $100 and up, and if you can replace the clutch yourself, I would recommend doing so, cause the AX15 isnt so easy to rebuild in my opinion.

I thought I would add a little clarification, in case it makes a difference... The noise I was getting originally with third gear was kind of a whirring chatter that was related to vehicle speed, not engine speed, if that makes sense, and I was getting the noise when I was in third and was decelerating (not necessarily braking, just letting the vehicle slow, if I was approaching a red light a ways off, for instance). I'm wondering now whether this indicates a problem in the transmission, rather than the clutch...? The last time I had it in, they looked at the transmission fluid and said it was due for replacement, as it was looking funky.

I looked at the fluid in the master clutch cylinder. It appears to be slightly (maybe 1/8" to 1/4") below the line in the reservoir. Is that enough to cause the problem?