Clutch stopped disengaging
 

Hello all,

1999 XJ with the 4.0L and AX15

Ive had a few instances of partial clutch disengagement, where the vehicle could lurch forward upon shifting into first from a stop. It also has been difficult to shift into 1st or 2nd a few times when stopped (much easier when the vehicle is moving)

Today, the vehicle made a low growl when the clutch pedal was depressed, and a higher pitch chatter / “angry squirrel” sound when moving the vehicle from a stop.

After driving around for a bit, I now cannot shift into any gear (from stop or rolling).

What should be on my check list and the priority/order of item?

What I have on the list:
1. Fluid check in clutch master cyl (unit was replaced 1 year ago)
2. Piston operation of clutch external slave cyl
3. Dig into the clutch / transmission.

I have not worked on a clutch / transmission. What can be inspected without removing the transmission? Or should I just remove the unit to begin my inspection?

Sounds like a bad throwout bearing to me.

Les likely would be the pilot bearing in the end of the crankshaft. I had that seize and it chewed up end of the input shaft and took out the trans input bearing. The vehicle would try to move with the clutch pressed in and baulk going into gear, and I thought it was the throwout initially as well. If you replace the trans fluid, do a search on recommended fluids - MTL, Redline, synchromesh, 10W-30, etc - anything but off the shelf GL4 or GL5 gear oil which is not friendly to the brass synchros in the AX15 and doesn't shift well.

I have to concur with lawsoncl - throwout bearing is a prime suspect. It could also be an issue with the pressure plate. I once had a spring break on my TJ and it sounded a lot like what you're describing.

Either way, you're pulling the transmission to deal with it if it's one of those possibilities.

I'd put some good fluid in it, check that the slave cylinder is good - see if the fork seems to be swinging correctly (you can push on the fork through the mounting hole for the slave cylinder without removing the tranny - though this may require some "feel" for what's correct vs. bad.).

If that doesn't help (and I don't expect that it will) then you can get a usable transmission jack at Harbor Freight for like $130-ish and then enlist a helper and give yourself a good weekend and pull the tranny.
The hardest part is getting the top 2 Inverse Torx (E-something) bolts off the bell housing (lots of extensions and patience -- do them FIRST) and getting the transmission to line up upon re-installation. I've always done it with the transfer case attached, but I expect removing the transfer case would make this part easier. In my case, rusty bolts made removing the transfer case less appealing than struggling to mate the tranny to the block.

When looking at transmission jacks, the dedicated one that is like a floor jack with good wheels is helpful. The jacks that attach to a floor jack have 2 issues that make them less convenient - they generally require the vehicle be raised higher (in other words, less flexibility with up/down room) and the wheels make maneuverability more difficult.

The AX15 is something like 90lbs empty, so it's manageable by hand (if you have a legit lift in your garage) and the transfer case is like 70lbs empty. So you COULD remove these by hand (some folks suggest supporting it on your stomach - please don't do this!) but 160+ lbs of heavy parts is plenty enough to cause serious injury or death if not handled correctly - so please - for the love of god - be safe with whatever you do. A good jack with a safety chain should be used. It's awful hard to shift with a crushed hand.

Thanks for the replies. I really appreciate it. I’ve had MT90 fluid in the AX15 since 2012.

I got the vehicle to a shop (dealership, as it was the only shop within my 5 mile free tow). Mechanic feels like it’s in the clutch/pressure plate/ throw out bearing area. They want to drop the trans and install a new clutch kit. $1600 parts & labor.

Novak sells brand new AX15s directly from Aisin for $1600, but with a 5-7 day lead time to arrival.

Dealership said labor to swap the new trans and install new clutch kit would be $1000.

So, $1600 vs $2600 at dealership or I get it towed to another shop with lower labor cost but have to pay for the tow.

Or I go down one of the two DIY routes (clutch kit only vs kit + new ax15).

Sounds about right - 10 hours labor.. interesting that they want 600 for a clutch kit.. A clutch kit is like $100 retail..

It's almost certainly NOT the AX15 unit itself - so I would not replace the unit unless you're -certain- it's bad.

If you have 3 days you can dedicate to replace it, and someone to help (plus hand tools, jack stands, floor jack, etc), I'd buy a tranny jack, clutch kit and do it yourself. Nothing is terribly difficult with the job, it's just a lot of work to remove the tranny and put it back together. You'll spend > 500 on the jack and parts and probably 20+ hours of your time.

It blows my mind - they want 1600 to do the same job (actually LESS work if they don't separate the transfer case!) they quote you 1000 for!!!

I just wanted to give an update.

I ended up servicing the AX15 myself using OEM components. New clutch, pressure plate, throwout bearing, and pilot bearing. The pilot bearing was missing some of the needles and the throwout had definitely seen better days.

This work solved several problems I've been experiencing over the past ~20K miles:

1. As the vehicle heated up, the clutch pedal required more force to depress (really making it a chore to drive)
2. As the vehicle heated up, the clutch disengagement got worse (making shifts from a stop and into reverse very difficult)
3. As the vehicle heated up, the engine would drop to idle very fast between shifts and I would have to use the gas pedal to RPM match.

It feels great to drive again and now I know what shifting issues were caused by the lack of clutch disengagement vs. the shifting issues still present from the 1st/2nd gear synchros (only minor at this time).

Cool, glad to hear that part is done. For the shifting, what fluid do you have in the trans? Getting the right oil in there can make a world of difference in how well the synchros work. When I rebuilt my ax-15, I initially put in cheap GL4 intending to drain after a week and put in Redline MTL. It shifted so bad I thought I screwed up the rebuild. Drained and refilled with a 50/50 mix of Redline MTL and MTL90 and it shifted beautifully. I understand even the dealers are refilling the ax-15 with Mobil 10w30.

Minor tip from the BTDT department - make sure you can remove the oil fill plug before removing the drain plug.

Oh, man, that's great! As I was reading down this thread, I was formulating a response in my mind to the effect of, YOU CAN DO THIS!

I"m glad you did! Not only did you save a bunch of bucks, you learned some things about your car, and better yet, about yourself. You stretched yourself and won.

:thumbup1::thumbup1:

MT90 all the way! I’ve been using it since 2012.

Appreciate it man!

Damn it Marky! You beat me to it!

We knew you could do it. All you needed was a push. (and saving money, LOL!) Remember, we got your 6!