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Transmission/Clutch issues. Grind, chatter, disengagement issues

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Hi Forum,

I'm at a loss with what to do next on my TJ and need some help. It is a 1999 4.0L with an AX15. 123,000 miles.

Sorry for the long post. This has been a year in the making. I've googled and read extensively and have exhausted every option/solution I know of short of replacing the transmission. I want to make sure that is my only next step before I pull the trigger.

A while back I drove it through high water, I didn't get stuck, but it was to the door handles and I got out very slowly. Shortly after, I started having a slight grind into 3rd only when the jeep was warm. If I let the RPMs come all of the way down before shifting into 3rd, it wouldn't grind most times.

I changed out the tranny fluid to 10w30, ran it for 1,000 miles, then switched to Syncromesh. Didn't fix the issue.

It started grinding into 5th too, every time. No amount of RPM matching, slow shifting, or double clutching will resolve this.

Then I noticed that it wouldn't roll backwards on an incline when in 1st with the clutch fully depressed. And wouldn't roll forward in reverse the same. It will roll backwards when in 3rd to 5th gear though. It won't shift into 1st or reverse when rolling the opposite direction even slightly. If I'm on a steep enough incline, it will roll, but with resistance and chatter. Here is a video of it.


So I began thinking it was a clutch disengagement issue. Replaced the master and slave cylinders. Bought as individual units and bench bled them. Didn't fix it.

I bought a Luk clutch kit. Replaced the pilot and throw out bearings, pressure plate, and clutch disk. The clip on the fork was broken, so I replaced that (it may have broken when I disassembled it). Sanded the flywheel. Put it all back together...no fix.

I though I may have bought a bad master or slave, or didn't do a good enough job bleeding it. So I bought a sealed master and slave unit from Napa. No fix.

When driving it, I noticed that when rolling in neutral at about 20mph WITHOUT pressing the clutch pedal and with the shifter centered in neutral, it chatters. While it is chattering, I can't shift into any gear. Once the chatter stops, I am able to press the clutch and shift. While it is chattering, if I pull the shifter towards a gear, without pressing the clutch still, the chatter stops. Since this has nothing to do with the clutch, I'm thinking that it isn't a clutch issue. Here is a video of it.

I'm at a loss for what to do next. I think it is the tranny (in light of the water) and probably needs to be rebuilt, but before I pull it and spend $700 on a rebuilt AX15, is there anything else I should look into based on these symptoms? Could it be a shifter problem, tranny mount issue (seems fine, but I may just not know what to look for), flywheel issue since I didn't replace it (seemed fine, no cracks)?

Sorry for the long post, and thanks in advance for the help.
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· Mostly old school..!
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12,152 Posts
Sounds like his clutch is not releasing

If it won't roll freely in a low gear with clutch all the way down the. That would be my guess

Find a flat parking lot away from everyone shut the jeep off and with transfer case in 2 hi and tranny in first and Park brake off and no foot on brake pedal now with clutch pedal all the way down still no brake and leave tranny in gear and crank the starter.
Does the jeep move forward when starter spins the engine?
I agree.
 

· Mostly old school..!
Joined
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12,152 Posts
If it isn't clutch related, there has to be something locking up/binding in some other part of the drive train. If different gears produce different amounts of resistance, my guess is that it would have to be an alignment issue between input and main shaft of the transmission.....possibly a transmission input shaft bearing that's toast?

You might want to pull the rear drive shaft, and have someone depress the clutch while you turn the t-case out put shaft by hand. If it still is binding up, start it up and use a mechanics stethoscope to see if you can pinpoint the noise.
 

· Mostly old school..!
Joined
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12,152 Posts
I'm thinking if the symptoms are exactly the same as they were before replacing all the clutch parts, and you're sure all the clutch parts were installed correctly, that leaves transmission. Since you have to pull the transmission to get to either one anyway, it seems to me the best option would be to pull it, recheck your clutch install and check the operation of the transmission out of the jeep.
 
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