Gearbox help please

[rathgar]

I developed a grinding noise last night whilst driving and with further testing have established that; it seems to be coming from the gearbox, it is evident in third gear only, not all the time but happens frequently (to frequently), doesn't matter whether its high or low range or if centre diff is locked, doesn't seem to be jumping out of gear or losing drive but does sound like the gear is not properly engaged, can happen under power or on overrun, keeping pressure on the lever doesn't prevent it.

What might be going on? I've removed the foam block around the lever and it made no diffidence. Just about to pull the top cover for a look and check the springs and balls.

Help Please!!

[Bearman]

Hard to diagnose from those symptoms but it could be any of the following
1............................3/4 synchro unit
2............................mainshaft front needle roller bearing failure possibly with journal surface erosion.
3............................input shaft bearing retaining tabs.
My guess would be the mainshaft front needle roller - afraid it's a box out job to find out/fix

[rathgar]

Thanks Brian, not what I wanted to hear. Is there any more to be seen through the top cover before removing the box?

[rathgar]

Can it be driven while I sort something out (avoiding 3rd) or am I risking more damage?

[Bearman]

Probably not but you could take the top off and have a look - never know you might find something.

[Bearman]

Can it be driven while I sort something out (avoiding 3rd) or am I risking more damage?

Depends what it is as to whether you do more damage.

[rathgar]

Hard to diagnose from those symptoms but it could be any of the following
1............................3/4 synchro unit
2............................mainshaft front needle roller bearing failure possibly with journal surface erosion.
3............................input shaft bearing retaining tabs.
My guess would be the mainshaft front needle roller - afraid it's a box out job to find out/fix

Haven't had a chance to look much more at this but did a bit more testing today and the noise is not just in third but in all gears and I can know get it to do it stationary (with transfer case in neutral).

I'm thinking it might be clutch related. Release bearing? spigot bearing? when its making the noise and you depress the clutch it feels "different" to normal.

Either way looks like the box is coming out.

[DAMINK]

Thrust bearing?
If so let it squeak. No biggy.
Replace when you can.

[rathgar]

Finally got a chance to have a look at the 110.

I am now sure that the noise is coming from clutch release mechanism but not the bearing. The Sleeve extension (Part # R571738) has been rubbing on the front cover (Part # R576340), there are visible rubbing marks, this has been caused by the release arm pivot point coming apart allowing excess movement, hence the loose feel in the clutch when the noise was evident. The sleeve extension has previously been tack welded to the front cover these welds have broken. Is this a known cure to prevent movement of the extension or some army mechanics bodge? Should the extension be free to move?

Are there any improvements to had to the retaining system for the release arm pivot point. Doesn't seem like the best system of retaining to me. Not to mention the plastic "staple"to retain the release bearing to the arm.

Thanks

Ian

[Bearman]

That is a problem with some of the mods the army did to the box. The extension sleeve is better off being peened and loctited instead of welded on. The stresses involved with tacking it are not what you want on an input shaft unless set up precisely in a jig. The pivot post is a known weak spot with the rattling the Suzi gives it. Again loctite is a good remedy if the hole is still normal but if there is any looseness the answer is to fit a pivot pin with a threaded extension and nyloc locknut to go right through the bellhosing where it is mounted. If the extension sleeve is rattling around loose in there the next thing it is going to stuff is the diaphragm on the pressure plate. If this is what it is you are going to have to pull the box unfortunately.