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Unread 06-16-2011, 03:08 PM   #1
plym49
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AX-15 Shifts No More

My AX-15 shifter locked. It happened as has been reported by others: no prior indication of a problem in the tranny, driving along normally on the highway in 5th, go to slow down for an exit, the shift lever moves out of fifth but could not engage fourth. Coast to a stop. Cannot engage any gear at all. Shift lever only moves side to side in neutral. Engine runs no problem (so no locking at the front). Car rolls (so no locking in the rear). No matter if engine is running or not, if clutch is engaged or not, or if vehicle is rolling or not, cannot engage any gear. Removed shift lever at the side of the road and could not see anything that would help - although - the seal under the shift lever was dried and cracked and a couple of large pieces were missing. maybe they went inside, and maybe they jammed something up. I kind of doubt that a piece of rubber could so thoroughly jam up a steel mechanism, though. We'll see.

Removed skid plate, transfer case, detent balls and springs. Still can't select a gear. Loosened intermediate plate - cannot see any problems inside, but intermediate plate did not come off. It is hung up on a shift rail or something.

That's where we are for now.

I will continue to report on what is found. In the mean time, I welcome any comments and also might be interested in a known good AX-15 replacement (hopefully, will not be needed but bets are off until I see what is going on inside).

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Unread 06-16-2011, 03:47 PM   #2
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Interesting--seems there is a sudden rash of stuck shifter/transmission inquiries. Nathanninja has one going just a few lines below yours with a similar problem, and I know there was another one this week with a "5th to 4th downshift and frozen" issue. It looks like you're soon going to pull the tranny. I'd get the rear case off of it and see if there is anything you can see back there, like the shifter synchro keys on the 5th reverse hub wedged out and ground into a synchro. Look thru Mean Max's major repair AX 15 thread that has all the photos of a tear down and rebuild. Please let us know what you find.
You can't pull the intermediate plate without getting the front bearing retainer off and removing the snaprings from the main and counter gear bearings from the front of the front case, then you can pull the intermediate plate with all the "guts".

Take a few moments to be thankful that it isn't winter and you're laying under it in the snow........

Let us all know what you find as there are about 3 threads active in the past 2 days on this topic alone and we haven't had a definitive find as of yet.

Here's Max's thread: http://www.jeepforum.com/forum/f12/m...build-1032480/
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We will be going Metric every inch of the way.
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Originally Posted by 40dog View Post
yes I'm a some guy and have always put gasket sealer on my surfaces before mating
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You should go to Pirate. I hear they are real smart over there. You'd fit right in.
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Unread 06-16-2011, 06:03 PM   #3
plym49
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Quote:
Originally Posted by Opihi59 View Post
Interesting--seems there is a sudden rash of stuck shifter/transmission inquiries. Nathanninja has one going just a few lines below yours with a similar problem, and I know there was another one this week with a "5th to 4th downshift and frozen" issue. It looks like you're soon going to pull the tranny. I'd get the rear case off of it and see if there is anything you can see back there, like the shifter synchro keys on the 5th reverse hub wedged out and ground into a synchro. Look thru Mean Max's major repair AX 15 thread that has all the photos of a tear down and rebuild. Please let us know what you find.
You can't pull the intermediate plate without getting the front bearing retainer off and removing the snaprings from the main and counter gear bearings from the front of the front case, then you can pull the intermediate plate with all the "guts".

Take a few moments to be thankful that it isn't winter and you're laying under it in the snow........

Let us all know what you find as there are about 3 threads active in the past 2 days on this topic alone and we haven't had a definitive find as of yet.

Here's Max's thread: http://www.jeepforum.com/forum/f12/m...build-1032480/
Thanks for the feedback. I've already looked at Mean Max's rebuild thread - I spotted it earlier from one of the threads you mention.

I am not with my Jeep or doing much of the repair myself, only because the failure occurred - unfortunately - on a road trip but - fortunately - within spitting distance of my best friend's shop - and he is good. So it is in good hands. I drove out to see it last night and they had gotten as far as (almost) getting the intermediate plate out, as described.

I returned with the skid plate so that I can attend to some PO buggering of the 6 places where it attaches to the frame.

We have already decided that this transmission is coming all the way apart as we want to do a good autopsy. It's funny what you mention about several of these coming up at the same time. When it happened, I googled the problem and found the same symptons/situation reported in old posts but with no definitive cause. It's about time that we shed more light on this seemingly common AX-15 failure mode. My bad luck (with the others) to have had it happen.

For what it is worth, while I do not know what kind of life my YJ lived before I got it (although it clearly spent some time as a highway commuter), the driveline had not been abused while I have had it, and also the failure occurred in the midst of completely normal driving. Also, it is significant that neither the input end or the output end is locked up. This leads me to believe that something comes loose inside that jams things up this way.

Film at 11: as we get into it, I will report all that we find.

In the mean time, again, would be happy to hear from anyone who has opened up an AX-15 that had this problem.
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Unread 06-16-2011, 06:50 PM   #4
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See my reply in this thread. I think you have the same issue.

http://www.jeepforum.com/forum/f12/a...oblem-1227479/

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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 06-16-2011, 07:22 PM   #5
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See my reply in this thread. I think you have the same issue.

http://www.jeepforum.com/forum/f12/a...oblem-1227479/

Max
Yes, that makes sense. It is as if the syncros/gears know that the tranny is in neutral, but that the shift rails think it is still in gear - and probably fifth, since that was the last gear engaged.

If this is it, how do you tell with the transfer case removed and the intermediate plate loose and back a half inch? Can this be repaired without taking it all down? At this point, from having removed the springs and balls, I believe that it is thought that the rails are not the culprit. (This is an important point that I may not be able to clarify for a day or two.)
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Unread 06-16-2011, 07:53 PM   #6
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I rebuild several AX5 & AX-15 transmissions a month now. Honestly, I would just pull down & fully disassemble it on the bench.

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Max has a picture of every Jeep part ever made.
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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 06-16-2011, 07:56 PM   #7
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I rebuild several AX5 & AX-15 transmissions a month now. Honestly, I would just pull down & fully disassemble it on the bench.

Max
What kind of charge if you get one of these UPS'd to you based on the symptoms we seem to have?
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Unread 06-16-2011, 08:23 PM   #8
Mean Max
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I'm the cheapest Jeep transmission guy in the world. I won't do anything but a full rebuild, and I get $300 for the parts & $350 for building one on the bench. That's $650 total for a carry-in/carry-out job. If somebody needs me to pull the old one & reinstall it, I add another $350 for my time & the fluids etc. For a total of $1000 I have the local shops beat by almost half.

If additional parts are needed once I open it up, the price goes up only by the cost of the required additional parts.

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Max has a picture of every Jeep part ever made.
Quote:
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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.

There is no situation that cannot be improved with a small but well-placed explosive.
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Unread 06-24-2011, 07:52 PM   #9
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OK, it looks like we found the problem. This afternoon I drove out to my friend's shop and together we looked things over as he had the guts of the tranny out.

img00586-20110624-1340.jpg

img00580-20110624-1338.jpg

img00594-20110624-1538.jpg

img00595-20110624-1539.jpg

Now, in one of the many threads on this topic, someone - maybe Max or Ophi - said that the problem would be a cracked fifth speed synchro ring (I might not be using the correct nomenclature).

Anyway, whoever said that had it dead on. Notice the crack.

The crack allowed this ring to slightly expand its diameter. That in turn prevented the synchro ring from cleanly moving back and forth. The brass synchro itself was fine. Look closely in the second two photos and you will see the crack.

So, when I shifted out of fifth and attempted to downshift into fourth, remeber that the shift lever went into neutral and would not catch another gear, but that the tranny itself was really in neutral (as the motor did not stall and the wheels turned).

So, obviously, the ring moved enough for the tranny to get itself into neutral, but not far enough for the pins in the intermediate plate to be happy enough to permit another gear to be engaged. This is a good design as this 'gap' permits this component to fail without locking the rear wheels by getting into two gears at once, which could be disastrous.

So now the question is: do I replace just this part? The rest of the tranny looks perfect. If so, where do I get one? Or, should I just get an entirely rebuilt unit shipped out?
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Unread 06-24-2011, 10:05 PM   #10
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Replace the broken part. If your synchros and the bearings are good, then use them. It is a great opportunity to do a total rebuild, but if you just replace what is damaged, and the associated synchro that mates with the broken part then you should be good.

Looking at the guts of that tranny, it's just a beautiful thing........I really enjoy tearing into trannies.

Look at the parts available on Morris Jeep, or at Quadratec you will find the individual parts you need.
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Quote:
Originally Posted by Brian4.2 View Post
We will be going Metric every inch of the way.
Quote:
Originally Posted by 40dog View Post
yes I'm a some guy and have always put gasket sealer on my surfaces before mating
Quote:
Originally Posted by Virjeep View Post
You should go to Pirate. I hear they are real smart over there. You'd fit right in.
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Unread 06-25-2011, 10:34 AM   #11
plym49
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Originally Posted by Opihi59 View Post
Replace the broken part. If your synchros and the bearings are good, then use them. It is a great opportunity to do a total rebuild, but if you just replace what is damaged, and the associated synchro that mates with the broken part then you should be good.

Looking at the guts of that tranny, it's just a beautiful thing........I really enjoy tearing into trannies.

Look at the parts available on Morris Jeep, or at Quadratec you will find the individual parts you need.
Thanks for the lead. I have also been PMing our good friend Max as I would really like one rebuilt by him.
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Unread 06-25-2011, 10:37 AM   #12
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I also wonder why this particular component fails. I expect it is not strong enough. Do these things break over time, due to metal fatigue? Or do they fail when they decide they are under too much stress? When mine went I was towing my M-416 trailer at low highway speeds on level roads. The trailer and the Jeep were lightly loaded. Maybe fifth gear is not even strong enough for that? What have others experienced?
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Unread 06-25-2011, 11:57 AM   #13
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Well.........you're going to get a flurry of opinions. Here's mine. Overdrive is not a gear for towing a load in these rigs. (now comes a series of "well, I towed a ________________ (insert enormous volume of something here) for ____________ (insert long distance or well-known hazardous mountain road) and never had an issue" contributions from other forum members.

On my 81 Yota, I chewed up the splines for 5th gear (wrung them right off the shaft) from the cluster gear assembly. Twice. That was when I started rebuilding transmissions instead of just taking them apart to see how they worked. I also never had towed in this rig, but had hauled some loads 1400-1600 lbs in the bed. I never used OD again when I had a load, and then sold it when the 86 model year came out. The trans in that truck was the equivalent of the AX 5.

Generally a failure like you see there is a shock load effect, not a sustained pull. It could also be the hammering effect of a trailer loading/unloading/loading/unloading your drivetrain as you alternate from coasting, to pulling, coasting, pulling, etc. Of course, always shift gently......

Then again, some gear parts or part lots just don't get hardened properly in the manufacturing process, it if was over hardened in that particular production lot, that would make it brittle.

Max is extremely busy working more than the equivalent of 2 jobs. When you don't see him posting regularly in his favorite subject, then you know he's swamped. He'll answer the PM eventually. He likes using Consolidated Transmission for parts, but he may even have some of the parts you want laying around in his shop that he may send your way for less than what it would cost new. I'll look for a link to Consolidated and post it in.

I'd just replace that part and it's associated synchros, put it back in the Jeep and then smile and go drink beer.



Consolidated Transmissions
2850 W Airport Blvd
Sanford, FL 32771-1610
(407) 321-2055
(800) 578-8726
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Quote:
Originally Posted by Brian4.2 View Post
We will be going Metric every inch of the way.
Quote:
Originally Posted by 40dog View Post
yes I'm a some guy and have always put gasket sealer on my surfaces before mating
Quote:
Originally Posted by Virjeep View Post
You should go to Pirate. I hear they are real smart over there. You'd fit right in.

Last edited by Opihi59; 06-25-2011 at 12:12 PM.. Reason: Address for Consolidated
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Unread 06-25-2011, 05:10 PM   #14
plym49
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Quote:
Originally Posted by Opihi59 View Post
Well.........you're going to get a flurry of opinions. Here's mine. Overdrive is not a gear for towing a load in these rigs. (now comes a series of "well, I towed a ________________ (insert enormous volume of something here) for ____________ (insert long distance or well-known hazardous mountain road) and never had an issue" contributions from other forum members.

On my 81 Yota, I chewed up the splines for 5th gear (wrung them right off the shaft) from the cluster gear assembly. Twice. That was when I started rebuilding transmissions instead of just taking them apart to see how they worked. I also never had towed in this rig, but had hauled some loads 1400-1600 lbs in the bed. I never used OD again when I had a load, and then sold it when the 86 model year came out. The trans in that truck was the equivalent of the AX 5.

Generally a failure like you see there is a shock load effect, not a sustained pull. It could also be the hammering effect of a trailer loading/unloading/loading/unloading your drivetrain as you alternate from coasting, to pulling, coasting, pulling, etc. Of course, always shift gently......

Then again, some gear parts or part lots just don't get hardened properly in the manufacturing process, it if was over hardened in that particular production lot, that would make it brittle.

Max is extremely busy working more than the equivalent of 2 jobs. When you don't see him posting regularly in his favorite subject, then you know he's swamped. He'll answer the PM eventually. He likes using Consolidated Transmission for parts, but he may even have some of the parts you want laying around in his shop that he may send your way for less than what it would cost new. I'll look for a link to Consolidated and post it in.

I'd just replace that part and it's associated synchros, put it back in the Jeep and then smile and go drink beer.



Consolidated Transmissions
2850 W Airport Blvd
Sanford, FL 32771-1610
(407) 321-2055
(800) 578-8726

I don't disagree. I do know I was pulling a light trailer that had a bulky yet light load, cruising was easy (no loading and unloading) and I shift as smoothly as a high-priced chauffeur. The gross weight of the entire rig was less than four adults and their gear.

I don't know what kind of abuse my Jeep had in prior lives nor whether the part that failed was part of a bad batch. I suspect, though, and failing any hard evidence to the contrary, that I will think long and hard before towing in fifth.

The balance between just fixing it and going all-out has other factors at play. Due to schedules, my friend (Jeep is at his shop a fair distance away) and I are both out-of-pocket for the next two weeks. If I decide to just fix it, there is a chance I could have the heep back before three weeks go by.

On the other hand, I am from the school of thought that when one thing fails, you rebuild or replace the upstream component or device. I keep my vehicles for a long time and I depend on them, so I practice this more 'aircraft' type of repair philosophy. This is to both reduce the chance of an subsequent breakage (whether related or not) and not having to take the vehicle out of service twice or take the same thing apart twice.

Max and I have been PMing and one just came in. Let me go see what he has to say.
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Unread 06-25-2011, 05:16 PM   #15
Opihi59
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I also have a tendency to "rig for silent running." Meaning I go overboard and fix everything in the system. When I bought my first Jeep and drained the tranny, I got choc. milk/mocha coffee out of it. I pulled it out and rebuilt the entire thing because I didn't know how long it had been that way.

Depending on budget, resources and time though I am sure you'll make the choice that works for you the best. It's good to have Max onboard though.
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Quote:
Originally Posted by Brian4.2 View Post
We will be going Metric every inch of the way.
Quote:
Originally Posted by 40dog View Post
yes I'm a some guy and have always put gasket sealer on my surfaces before mating
Quote:
Originally Posted by Virjeep View Post
You should go to Pirate. I hear they are real smart over there. You'd fit right in.

Last edited by Opihi59; 07-07-2012 at 03:38 PM.. Reason: spelling
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