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Unread 02-23-2013, 10:10 PM   #1
RenoF250
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Help! AX15 seems to be stuck in 4th

I just put my AX-15 back together and all appeared good. Followed the book, no parts missing or extra, pics together match pics before etc. Anyhow, it turns in 4th and neutral but in any other gear it is stuck like it is in 4th + whatever gear. I took pics before I put the case on and it sure appears that the 3-4 selector is in neutral but it is not behaving that way. Any ideas?

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Unread 02-23-2013, 10:16 PM   #2
Mean Max
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It sounds like you might have the syncro for 4th out of alignment. Specifically, the 3 hub key cutouts.

Max
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No one here knows what they are talking about. You should try Pirate 4x4 they will be happy to help you.

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Unread 02-23-2013, 11:26 PM   #3
RenoF250
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I pulled it apart before the RTV dried and the 4th synchro was jammed on. I pried it off with a screwdriver and now it works fine. Put it together with no RTV and it works fine. I made sure all of the synchros engaged the keys properly. Something apparently jammed it on. The thing that really concerns me is the reason I am rebuilding this transmission is the 3-4 keys were broken. This seems like just the sort of problem that would break the keys. Is there something wrong with the pilot shaft or is this just a coincidence?
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Unread 02-23-2013, 11:47 PM   #4
Mean Max
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I've had 4th gear syncros get jammed onto the input shaft before myself. It hasn't happened to me since I started loading the syncros grease while installing them.

As for the original condition regarding the broken 3-4 keys, I've never seen that before. Were they all broken? Was the hub shift sleeve on correctly, chamfered edge to the front?

Is the pilot bearing present/correct?

Max
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Quote:
Originally Posted by Benderff View Post
No one here knows what they are talking about. You should try Pirate 4x4 they will be happy to help you.

There is no situation that cannot be improved with a small but well-placed explosive.
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Unread 02-24-2013, 12:25 AM   #5
RenoF250
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Originally Posted by Mean Max View Post
I've had 4th gear syncros get jammed onto the input shaft before myself. It hasn't happened to me since I started loading the syncros grease while installing them.

As for the original condition regarding the broken 3-4 keys, I've never seen that before. Were they all broken? Was the hub shift sleeve on correctly, chamfered edge to the front?

Is the pilot bearing present/correct?

Max
Yes, all 3 were broken and both 3 and 4 synchros toast. Also front and rear sealed bearings had bubbled plastic other than that no damage that I saw. It appeared to be the factory build. I cannot comment on the pilot bearing, I bought if from a guy on CL already out. The synchros were all completely worn out so that they were bottoming out on the ramp.
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Unread 02-24-2013, 05:42 AM   #6
Mean Max
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The bubbling sealed bearing condition is typical.

Syncros in the AX-5 & AX-15 transmissions most commonly wear on the backside, where the keys engage, rather than on the cone side. This seems unusual.

I've never seen the keys broken, ever. I would really have liked to been in on the teardown & rebuild for this one.

Ensure that you have the correct pilot bearing installed, early AX-15 transmissions use a smaller 0.590" pilot tip, while later models use a 0.750" pilot tip dimension.

Max
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Quote:
Originally Posted by UltimatE View Post
Max has a picture of every Jeep part ever made.
Quote:
Originally Posted by Benderff View Post
No one here knows what they are talking about. You should try Pirate 4x4 they will be happy to help you.

There is no situation that cannot be improved with a small but well-placed explosive.
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Unread 02-24-2013, 12:04 PM   #7
RenoF250
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Quote:
Originally Posted by Mean Max View Post
The bubbling sealed bearing condition is typical.

Syncros in the AX-5 & AX-15 transmissions most commonly wear on the backside, where the keys engage, rather than on the cone side. This seems unusual.

I've never seen the keys broken, ever. I would really have liked to been in on the teardown & rebuild for this one.

Ensure that you have the correct pilot bearing installed, early AX-15 transmissions use a smaller 0.590" pilot tip, while later models use a 0.750" pilot tip dimension.

Max
I took quite a few pictures of it as I took it apart and still have all the pieces including the broken keys. PM an e-mail and I will send them to you. Too big for me to put all of them on here.

There was some light varnish on the synchro ramps of the gears, I cleaned it off with red scotchbrite.
ax15-before.jpg  
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Unread 02-24-2013, 12:44 PM   #8
RenoF250
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Here are some shots of the old synchros. You can see they had all worn to the point that their backs were touching. 3 and 4 are chewed up as well.
old-synchros-1-.jpg   old-synchros.jpg  
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Unread 02-24-2013, 12:48 PM   #9
RenoF250
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The new synchros for 3 and 4 are different, ramped on one edge and straight on the other. Have you seen this before?
new-synchro.jpg  
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Unread 02-27-2013, 10:00 PM   #10
RenoF250
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I was shifting it with the case off and got 3rd synchro jammed the same way. That is a bit concerning. I hope once it is bathed in oil it does not have that problem. It is all together now. Goes through all the gears and N but 5th is a bit of a pain to go in.
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