Poorly AX15?

Chancer · Jun 10, 2005

Right. I've searched through, but haven't come across anything that really covers this, so I shall list the symptoms.

1: Ages back I noticed a sharp, distinct 'clack' sound when I was taking my foot off the clutch, particularly from a standstill. The problem's worse if I pull away hard, and it seems to occur halfway through the bite (possibly at the bite point itself), rather than when you release the clutch fully. It's never really gone away.

2: Shifting is OK - it goes into gear pretty much fine, except for 2nd, first thing in the morning, but it is really clunky, and appears to be progressively getting worse. It is also quite hard to change gear smoothly, and there seems to be takeup in the drivetrain as well, so it made me wonder about driveshaft UJ's or something that have worn because of the heavy shifting.

3: At about 2500rpm it sounds like somebody's dropped a bag of marbles into the gearbox casing, especially in 5th and under load. I also get the same noise if I'm pulling hard, say, if I'm overtaking.

I know that at 160k the tranny's getting on a bit, but is there clutch adjustment that can be done, or should I be looking at getting it out for a refurb/ full overhaul?

RichP · Jun 10, 2005

My AX 15 in my 98 has 260,000mi plus on it, when I first got it in dec of 97 that first winter 2nd gear was very cold blooded in the mornings, especially in cold weather [10f-40f]. Before all the GL3 issues and the ax15 came out I switched to mobil-1 gear oil, smoothed 2nd right out and made shifting alot easier, I have had mobil-1 in there ever since, changed it twice but I'm running out of the case of gear oil I bought back then and have ordered a few quarts of Redline MTS to replace the mobil-1 with. Don't know about the noises, I'd suggest you drain your gear oil and use a clean container, maybe with a filter like for automotive paints, look for any bits of metal or bronze in there.

bajacalal · Jun 10, 2005

Chancer said:
Right. I've searched through, but haven't come across anything that really covers this, so I shall list the symptoms.

1.) Have you checked the u joints, splined slip yoke and axle for free play?
Also, could the clutch cylinder have air/water it, causing the rough shifting and jerky engagement? Check for complete disengagement. Can you go from 1st to R after a few seconds with the clutch pushed down, no grinding? Do you know what slave cyl. you have, the external (self adjusting) or internal thats part of the throwout bearing? What year? The external on mine wants pumped a few times if the jeep hasn't been driven recently. The clutch system is hydraulic, no adjustment but sometimes can be bleed, the cylinder can also fail.
2) Change the fluid. The full synthetic Redline MT-90 isbe a good idea, it seems to be made for problem trannys. You order it for $8/qt here, takes 3.3 quarts, I don't know where you could get it. I also put 1/2 pt. of the Lubeguard manual transmission additive, apparently one of the few additives recommended my auto makers (don't know about jeep though). The AX15 wont be happy with gl5 axle grease containing sulphur. With the MT90/Lubeguard I run in mine, its pretty smooth. Check the fluid contents for particles, a little fine dust is ok, lots of it or large bits, not so ok. Don't neglet the t-case either, put some synthetic (automatic) transmission fluid in. I double clutch the tranny when downshifting with load. Makes it much smoother, remember its not a sportscar.
3) The noise could be driveline vibrations from work u joints or could be mistaken trans noise for engine knock/ping? When it does the noise, lightly tap the shifter upwards. Would a worn bushing cause the incomplete engagement of 5th? If the all the gears whine or the synchros start failing it might need rebuilt.

Just some ideas.

Dobbs · Jun 10, 2005

I would say its the front input bearing. Mine went bad and sound just like what you have . The tran is easy to pull and disamble the front bearing is another thing there is two bearings the only way you can tell what one you need is to disamble it .mine cost about 50.00 for the bearing or a kit for about 190.00 >but you still have to take it apart to know wich bearing to use one is about a 1/4 in thicker than the other.If you need any more info on this let me know done mine last mo

Chancer · Jun 12, 2005

I'm sure a change to synthetic would make a difference. I changed all the fluids back in the winter, and have only done about 3000 miles since, but just changed to bog standard GL5 (since I got it cheap...).

It's a 1993, and I have no idea about the slave cylinder. It's always been a bit clunky going into reverse, but today I noticed a new sound: I was reversing a big trailer and there was a continuous groan/ moan. I guess it was compaling about the load. Can't blame it really!

I know this is a stupid question, but what does pinging sound like? The engine's a bit tappity, and there's a funny gurgling sound, almost like water down a plughole, when cruising in 5th, but since I've never known pinging, I don't know what to listen for.

Worn UJs are a possibility - I'll have a look underneath. Should there be takeup or slack in the drivetrain if it's not in gear? I can rotate the drive shaft a little when underneath, but never thought much about that.

If it is anything like input bearings, worn shifter forks or the like, is there any easy test for it, apart from getting a gearbox specialist to diagnose it for me?

TIA

RichP · Jun 12, 2005

If you are using GL5 lube that might be a problem, all the asins use GL3 because of the sintered bearings, the GL5 lubes have a high sulphur content which eats bronze, gl3 does not.

Poorly AX15?

Chancer

NAXJA Forum User

RichP

NAXJA Forum User

bajacalal

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Dobbs

NAXJA Forum User

Chancer

NAXJA Forum User

RichP

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