Hard to shift when engine is hot

[96Cherokee]

Hi all!  I have a '96 Cherokee 4.0L with about 345,000km on it.  I've had it since new.  I'm finding now that when I'm off-roading especially, it seems like it gets hard to shift.  I have a feeling that it's temperature related.  I like taking things slow and technical, but also go through some decent mud puddles which one may find oneself rocking back and forth to get out of.  It's then that I notice the biggest problem between switching gears.  It gets REALLY stiff, and even grinds here and there.

I'm still on my original clutch, even though the jeep stealarships recommended I get a new one at 100,000 back when I used to go to them.  Everyday driving is fine with it still, and my mechanic says it's fine.  I have a feeling that this problem may be clutch fluid related, in that there might be air, or water, or maybe even I need to try DOT 4 not DOT 3.

Any ideas?

[jkrubi]

When was the last time that the fluid in the transimision was changed? As well as the clutch fluid?  As well what gears does it grind into? ie 1and rev.  Does it only grind when you are rocking it, and at high eng rpm.
           
 If its grinding into all forward gears when trying to rock out I'd say you need a new clutch.  When driving around town around town you are not as agressive on it and it wont grind.   Try shifting and high rpms and shift fast like you do when rocking out.

If it only does it in certain gears the the syncros are worn out and it will need to be replaced, you can get around it for awhile by doouble clutching but I'd start thinking about doing a tranny.

If it only grinds going into reverse, it should.  Rev does not have any syncro

With 300000+ kms on an orignal clutch I'd say change it, it owes you nothing.

If you think that there is air in the fluid bleed the system, if there is water in the system change the fluid. 

[mike s]

300+KM? And it grinds some times when being abused? 40 000 KM around the equator so it's been around the world how many times?  Change the tranny fluid to something decent and keep beating on it. Won't be. Clutch issue if it doesn't slip, but mud makes the clutch splines rust up making it drag when the clutch is held down, so it won't shift very nice. You SHOULD wait a few seconds with the clutch down before changing directions IE. Forward gears to reverse, to let the gears slow down inside the box and mesh better...but this is 4whln any we tend to abuse parts when we have to...

[SwampSinger]

Change your fluids in your tranny... do it yourself. Buy some good synthetic 75w90 (get a gallon of Lucas Synthetic 75W90 for $50 at Part source) and let the oil do its thing... you should notice a smoother shifting within a couple of weeks. I did that in my AX15 and it worked great for me. My syncros are hurting but now it shifts pretty good and it's been a few years since I did the switch.

[JackstandJohnny]

Change your fluids in your tranny... do it yourself. Buy some good synthetic 75w90 (get a gallon of Lucas Synthetic 75W90 for $50 at Part source) and let the oil do its thing... you should notice a smoother shifting within a couple of weeks. I did that in my AX15 and it worked great for me. My syncros are hurting but now it shifts pretty good and it's been a few years since I did the switch.

dom will that work better than ATF?  or should ATF NOT be run in an ax 15. gotta change mine. but havn't even checked whats in it 

[SwampSinger]

dom will that work better than ATF?  or should ATF NOT be run in an ax 15. gotta change mine. but havn't even checked whats in it 

Nope... some tranny runs with 80W90 but the Lucas stuff has additives that (what I have experienced) helps quite a bit. I used good synthetic 75W90 before (like mobile 1) and it also made a difference in shifting.

ATF is real thin oil...I used it in my T-case. I had a hard time shifting on 4 and 2 low with regular ATF. Since I put in royal purple synthetic ATF my issue is gone. Red Line , Lucas, Royal purple are all good oils. Some say it's BS and it's snake oil.  I know what I have tried and it work like a damn for me... so I'm sticking to it. The only down fall is the R.P. Synt. ATF is it's wicked thin and leaks a bit out of your fill and trail plug.

I think ATF might be too thin for manual trannies... Bill would know better