Rebuilt the AX-15 - still grinds???

So get this. About 3 weeks ago my third gear started grinding on me. It wouldn't always keep you out but it was definitely audible if you did get it in there. The shitty thing is that once ya did get in there, man you were good; cruise in it all day, no problem. So I decide to try the little stuff first. I dumped the fluids and topped her off with some Amsoil 75w-90 GL-4. No change. So I went a little further, shifter bushing; it could be cracked or damaged? Nope. Same symptoms.

What did I do after that? Bought some new syncros, some seals, some bearings, some more fluids and rebuilt that sucker. After a long weekend of degreasing, hunching over a press, heating bearings, pulling gears, etc... I finally get that puppy back together; quite proud of myself too. Anyways, I "bench" shifted it before I got everything back together and it worked great, so back in everything went. Then I set out for the all telling test drive.....

SAME SH*T! 3rd is STILL GRINDING!!!:banghead: WTF....

Can anyone suggest a next step for me? My next thought I guess is to replace the bushing the shifter actually sits on, not the one at the very bottom inside the shift arm (already replaced that one), but the one that supports the pivoting action of the shifter its self. My thought is that since I can throw it up there, with some grinds of course, that possibly its just not pushing the rail far enough... I don't know.. I just want my third gear back :tears:

So it only grinds when you shift into or out of it, but if you can magically get 3rd gear engaged, it's fine? And there are no signs of this in other gears?

What was the condition of the coupling rings? (The ring that goes over the syncros)

It only grinds as I release the clutch in 3rd. If I don't hold it up there with some force it'll pop it back at me. If I do hold it up there with some force, it'll grind and engage. It does not make any noise, nor does it feel rough, disengaging from 3rd. Every other gear shifts perfectly.

I noted no damage to any of the coupling rings, inserts, or spring clips. The syncro sleeve assemblies looked undamaged and there was no visible damage to the syncros I removed. The only thing I noted was the new syncros seem to fit slightly tighter on those journal surfaces they ride on (forgot what that part is called).

Hmmm... Have you ever power shifted before? (not using the clutch) I wonder what would happen if you tried power shifting into and out of 3rd.

When you were shifting it on the bench, did you have the whole handle mechanism on the top or did you just have something stuck in the shifter?

Also, did you measure to see if the shaft's end play was to spec? This one is a long shot...

The syncros fitting tighter makes sense.

Does it feel like it's engaging or does it feel sloppy? I know you're already on board with this idea, but just because the handle is where you think it should be doesn't mean everything inside is moving accordingly. Replacing the bushing you're talking about sounds logical and is easier and cheaper than tearing into the trans again...

Never tried power shifting as I'm too worried I'll destroy something past repair; these things don't exactly plague the junk yards...

When I was bench shifting it, I used a 1/2" socket wrench extension and could definitely tell it was engaging as you can note the change in ratio as you rotate the input shaft. Felt normal and crisp.

I did not measure the shaft end play but as you may know, the retaining clips for the main bearings will just barely go into place once you get it secured to the forward housing and the intermediate plate. Things don't really tighten up until you get it mostly back together...

When I push it up into third it feels as though it hasn't crested the hill, if that makes any sense. When you push it into any other gear you can feel at the end it has engaged. when I do it to third, I don't feel that last bite.

You don't think I could have put the shift tower on backwards, right? The breather is towards the rear as I have it right now. The shifter looks right in the cabin.

So I spoke with a buddy of mine that has rebuilt a few AX-15's and a few more AX-5's. He said it was pretty common that the larger 1-and-some-odd inch bushing that the shifter pivots on to wear out in the AX-5 and cause the shifter to drop further into the transmission.

Has anyone heard of that?

I called Jeep and apparently for the AX15 you must buy the entire shifter assembly and it costs around $260 and isn't available; so that's helpful.

I could buy that as the reason.

Id' probably find a friendly machine shop, have them hog out the shift tower to a standard size, then replace the bushing with a tapered brass unit. I'd get a tall tapered unit so you could cut it down and make it fit where the taper fit the ball on the shifter tight and in the proper position. Short of going yard diving you'll never find one, mines been damaged from day one and I've been on the lookout for years. They simply don't exist.

I wouldn't call my self a machinist by any means but I'm efficient enough with a lathe that I think I can handle the job. I've got some 2" solid stock of this material called Nylatron GSM; it's an oil impregnation plastic bearing material often used to cut down on cable wear with heavy lifting crane equipment. I'm going to pull my shifter tower and look at the one that is there. I'll remake it and lift it a little and just see if that helps.

I'll let you know how that goes...