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AX15 6yl, wont go into 1st or 2nd

O

Oizarod115

NAXJA Forum User
Location
Atlanta, GA
i have a stock 89 4.0, 4x4, mj with the AX15 tranny.

the last couple times ive started it up to leave ive noticed getting it into gear was a complete #&$^%. today i started it up and it wouldnt go in gear at all, i managed to pop it in reverse but then when i needed to go forwards the only gear that it would run was 3rd or 5th.

any help? anyone know whats up?
 
mine had this exact same problem. It was a bad slave cylinder.
 
alright, now i have new information.
the truck no longer goes in gear at all but will go in gear when the engine is cut off.
also i can put it in gear then start it up but when the clutch is on the floor it still acts like its halfway out, and the engine took forever to start.. and thats not like my jeep.

slave cylinder still?
 
Yup slave cylinder. When mine was off, I could shift to all gears, but the first time I shifted into 1st, you could feel the bind, then after that, every gear smooth. Start up, and you cannot shift, the clutch feels like it is still engaged (cause it is), and no shifty..
 
Your synchros may be sticking. When did you change trans oil in it last? (what kind of oil? They seem pretty fussy!) Check the master cyl for the fluid? It could be the pilot bearing in the back of the motor going bad (seizing onto the input shaft) or bellhousing bolts come loose, allowing the bell to twist a bit and bind the input shaft.
 
i just bought this MJ about 2 weeks ago and i always thought it had the AX15, but it may have the BA 10. from pics on the internet i think it looks more like a BA10.

would the culprit still be the slave cylinder?

thanks
-nick
 
It's a problem in the hydraulic system in general. My 87 MJ has a replaceable rubber hose in between the Master and slave. mine had gotten cooked by the exhaust. Something else to think about. You need to go over the whole clutch system. Make sure it's not losing fluid. It could be the Master cylider, hose or slave. Hose is easy, MC is a pain but doable in a few hours including bleeding. Slave cylinder requires removal of the bellhousing, so pray it's something else.
 
Oizarod115 said:
alright, now i have new information.
the truck no longer goes in gear at all but will go in gear when the engine is cut off.
also i can put it in gear then start it up but when the clutch is on the floor it still acts like its halfway out, and the engine took forever to start.. and thats not like my jeep.

slave cylinder still?
Click to expand...

Sounds like a clutch problem and not a synchro problem since it's not fully releasing. Has the XJ moved forward when cranking with the clutch in? Check that you have fluid in the clutch master cylinder and that the line leading down to the tranny isn't leaking (btdt). You could try bleeding the clutch line to see if it's air, but that's not too likely unless you ran out of hyd fluid.

Unfortunately, the next things to check require pulling the tranny to inspect the clutch, internal throwout slave/bearing, and the pilot bearing. I had the same symptoms except I kept getting an intermittent rumble with the clutch pushed in. I had rebuilt the tranny about 30k miles earlier and I think I damaged the throwout bearing during installation. It was disintegrated and tore up the end of the tranny input shaft. Not having the front of the shaft supported also took out the tranny input bearing.

Also keep in mind that the AX15 like high quality, non-sulfur additive gear oil. Cheap GL5 oil has sulfurs which attacks brass synchros when it gets above about 200* and tends to have hard shifting in cold weather. RedLine MTL worked great and the Napa GL5 stuff would hardly shift into 1st when it was below freezing until the ttranny warmed up.
 
--------------------------------------------------------------------------------

alright, now i have new information.
the truck no longer goes in gear at all but will go in gear when the engine is cut off.
also i can put it in gear then start it up but when the clutch is on the floor it still acts like its halfway out, and the engine took forever to start.. and thats not like my jeep.

slave cylinder still?
------------------------------------------------------------------------
I'm on my way to pick up my 1989 form the shop today.
My Jeep was doing exactly what yours is doing. EXACTLY!

I was SURE it was the syncro's and since I'm not skilled enough for that I bit the bullet and took it to a local shop expecting a rebuild.

Turns out it was the slave. While they had it out I had them install a new clutch kit and a MC too.

All for $800.00
 
I had the same issue in my 89 w/ the Puegot trans back in 97. I am much happier now w/ the 96 ax-15 w/ the slave external on the housing
 
i called the man who sold it to me and he says brand new clutch and slave (pretty much a complete rebuild) less than a year ago.

i beleive i have the peugot (which sucks :( ) but im not quite sure.

is there any possibility that its air in the lines? and i could just bleed it?

THANKS for all the help.
-nick
 
sure that's a possibility. Then you have to wonder how it got air in the system to begin with, since it worked ok previously. If the slave is indeed new, I woud suspect the master cylinder. When my master failed I didn't have any fluid loss, but I would have to "pump" the pedal to get the clutch to disengage. You really need to go and inspect the whole system.
 
Oizarod115 said:
i called the man who sold it to me and he says brand new clutch and slave (pretty much a complete rebuild) less than a year ago.
Click to expand...

Sounds like my case of messing up the pilot bearing during the install (I'm assuming based on the carnage I found). I'm still thinking you're going to have to pull the tranny.


-Chris
 
87manche said:
sure that's a possibility. Then you have to wonder how it got air in the system to begin with, since it worked ok previously. If the slave is indeed new, I woud suspect the master cylinder. When my master failed I didn't have any fluid loss, but I would have to "pump" the pedal to get the clutch to disengage. You really need to go and inspect the whole system.
Click to expand...

I'm REALLY hoping that no dissasembly of my tranny is required (and no trips to the mechanic) so i guess tonight ill try bleeding the system hopefully that will work. like you said though it could be the master cylinder cause i have no fluid loss.

appreciate the help guys.
-nick
 
Oizarod115 said:
I'm REALLY hoping that no dissasembly of my tranny is required (and no trips to the mechanic) so i guess tonight ill try bleeding the system hopefully that will work. like you said though it could be the master cylinder cause i have no fluid loss.

appreciate the help guys.

that you can see!......pull the carpet and liner back under tthe dash next to the fusebox.........if fluid is there you have a master cylinder leak.........If the resivor is still 100% full then bleead the system......In my old 4 speed MJ I had a small lead and a few drops of dextron III and the leak stopped for several years
-nick
Click to expand...
 
thanks for all the help but its gonna need a trip to the mechanic this time.
can't bleed it, and dont know how to tell if the other things are working right.
so off to the shop for a quick diagnosis.

thanks again
-nick
 
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