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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
In the process of rebuilding my ax-15 5spd 2wd transmission after suddenly going out on the side of the road. Have taken off the gear case and upon inspection of everything, I see that the main gear on the input shaft drive is shredded and grinded nearly flat, as well as the large gear at the end of the cluster gear is beat up pretty bad. Looks like these were the 2 gears that were together when it grinded to a hault. Also, when taking off the bellhousing, the clutch release fork just fell out and was not connected on one side with the spring or anything.
My question is, what could of caused the issue with the gears being shredded, the clutch not disengaging when I changed gears (which is right when the transmission blew?)
Was already planning on getting rebuild kit and new clutch kit, but now looks like I need a new input shaft & cluster gear assembly?
I was in 3rd gear, switched to 4th gear, and as soon as I did it all of a sudden made a horrible grinding sound and when would try to give it gas it would just shake violently. Thinking it is the sound of that flat input gear just rubbing against the cluster. Granted the transmission had been making a bad whining sound and was kicking out of 4th gear, I knew it needed to be rebuilt. 290K miles and all original. Just didn't expect to have to replace 2 gears along with the rebuild kit. I feel pretty confident in rebuilding it, just the part measuring tolerances with feeler gauges and such seems to have to be exactly precise. Will def keep thread updated. This is my 1st experience with a transmission but just taking it slow and have the rebuild manual for the ax-15 which helps....
I was in 3rd gear, switched to 4th gear, and as soon as I did it all of a sudden made a horrible grinding sound and when would try to give it gas it would just shake violently. Thinking it is the sound of that flat input gear just rubbing against the cluster. Granted the transmission had been making a bad whining sound and was kicking out of 4th gear, I knew it needed to be rebuilt. 290K miles and all original. Just didn't expect to have to replace 2 gears along with the rebuild kit. I feel pretty confident in rebuilding it, just the part measuring tolerances with feeler gauges and such seems to have to be exactly precise. Will def keep thread updated. This is my 1st experience with a transmission but just taking it slow and have the rebuild manual for the ax-15 which helps....
Yeah, I'll be following this thread closely and will ask that you document and post as you go. I love the AX15, my Dad put 400k on his (in a 94 XJ) and it worked flawlessly throughout the life of the vehicle and was in perfect shape when he retired the Jeep. I've got over 300k on the one in my 95 and it has run flawlessly in the year I've had the Jeep.
My last Jeep had the NV3550 and after about 300k it started making a pretty nasty bearing noise - I pulled it and the pilot bearing pretty much fell out of the flywheel, so I figured it was probably a bad input shaft bearing or something to that effect. Of course, that tranny failure was the last straw for the TJ as a daily driver (at the time it failed gas was at $4/gallon). It still drove, but I have no doubt that if I had kept on driving it eventually it would have had a more catastrophic failure such as the one you had. I ended up just putting the tranny back in as pulling the tranny apart myself was (and still pretty much is) a bit above my pay grade as a non-professional with no formal auto mechanic training and having nobody to advise/assist in-person.
I'm hoping I never have to consider a rebuild on my AX15, but as a manual tranny lover, I'm always interested in learning more about the inner workings.
To me it seems like the bearings may have been worn and had excessive movement allowing the gears to spread apart and wear the very edges of the teeth.
I would think that a bearing must have seized or something in the synchronization failed - the only way those gears would be ground down that much would be them both having forces that wanted them to spin at different speeds, right?
Looked at all the bearings and they seem to spin freely, not saying that they were out though. Also, on my clutch fork, when taking off the bellhousing, it just fell off. there was no spring. Am ordering the rebuild kit and replacing all the bearings and syncros etc......Amalso going to install a new clutch kit as well as obviously a new input shaft and cluster gear. Yeah, the grinding on those 2 gears looks horrible...
Engine: 4.3L with headers and full 3" exhaust system
Just a suggestion on this. You have undoubtedly gotten fillings in everything. What I would do is get any AX15, switch out your tail shaft and tail housing if needed for your 2WD application and call it good. You have so much damage there that it would be really expensive to make it like new. I think this is your best option, and if you want replace the synchros while you are at it
Not sure if I am understanding what you are saying 4.3. I still have my 2wd tail housing, and yes, there are filings all over, but all the other gears look fine except for the input shaft and a new cluster gear. In addition, was going to buy the master rebuild kit with new bearings, syncros, seals and pins etc.......So are you saying it still won't perform correctly after doing the rebuild kit, and getting a new input shaft and cluster gear? I have found a brand new input shaft for $79 and a new cluster gear for $149. Then of course the cost of the rebuild kit which I have found for $249. Should work like new after doing that I see no reason why not. But this is my 1st transmission experience. Thanks for all the help!
So basically just get a new AX-15 from the junkyard or such, and just do the rebuild/syncros on the new one, instead of replacing the cluster gear and input shaft on mine with the new syncros etc..?
So basically just get a new AX-15 from the junkyard or such, and just do the rebuild/syncros on the new one, instead of replacing the cluster gear and input shaft on mine with the new syncros etc..?
He's saying this may be a more cost effective solution. In the end it's your transmission and your jeep though. Do what would make you most comfortable in the end.
Oh ok gotcha! I see what he is saying. Just really hating the thought of having to pull another transmission out and disassemble...lol. Not the best of days, especially not having a lift :/
Will probably just take the $100-$200 hit and just get the parts needed for mine. Plus, piece of mind knowing the shape mine is in and having it rebuilt. I greatly appreciate all the input!
Oh ok gotcha! I see what he is saying. Just really hating the thought of having to pull another transmission out and disassemble...lol. Not the best of days, especially not having a lift :/
Will probably just take the $100-$200 hit and just get the parts needed for mine. Plus, piece of mind knowing the shape mine is in and having it rebuilt. I greatly appreciate all the input!
I think another key point was that the remnants of the gear teeth are now spread through the all the nooks and crannies in your current transmission. You will probably have to take your transmission down to unit parts (basically a complete disassembly) and clean everything to get rid of the filings.
As you mentioned, the tolerances are extremely tight on those parts and filings floating around could cause a quick failure and then you've gone to all that work (and cost of parts) and be right back where you are now.
12-04-2018, 12:40 PM
AX-15 Rebuild Question
