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.

[Bearman]

Forgot to mention, don't worry about the plastic staple, it does it's job in holding the release bearing off the pressure plate. That's all it does but it is a necessary part - nothing to worry about.

[rathgar]

.... pivot pin with a threaded extension and nyloc locknut to go right through the bellhosing where it is mounted. .....
Its not the mounting of the post that was the problem but the ball end of the pivot. The retaining of the ball end of the joint by the spring steel clip is not the most best set up.

The box is out now that's how I can see the issues with the input sleeve.

Thanks for your advice Bearman. Your expertise in these gearboxes is one of the most valuable resources of this forum.

[rathgar]

.... 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. .....

What Loctite product would you recommend? My research would make me think Loctite 660.

LOCTITE 660


http://hybris.cms.henkel.com/medias/sys_master/root/8814354399262/unbenannt-294678-.jpg
Retaining Compound - high strength. Gap filling. For repair of worn-out seats, keys, splines, bearings or tapers without remachining.
LOCTITE® 660 is designed for the bonding of cylindrical fitting parts, particularly where bond gaps occurs such with worn parts, without the need for remachining. The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration. This product exhibits excellent gap cure characteristics and is also suitable for retaining shims.

Your benefits


Ideal for repairing worn parts without remachining
Enables re-use of worn bearing seats, keys, splines or tapers
Suitable for retaining shims
P1 NSF Reg. No.: 123704

[Bearman]

That will be fine by the spec sheet. I just use 609 which I have a supply of for things like the distance sleeve on the mainshaft and the reverse idler shaft. Liberally coat the inside of the extension sleeve after you have cleaned it up and preferably prime it before you apply the loctite, then tap it home and leave it for a while

[rathgar]

Everything is now back together and running well. No nasty noises. It seems that that movement between the extension sleeve and front cover was the cause of the problem.

[Bearman]

Well done!

[DazzaTD5]

No nasty noises

wooooo woooo !! something is wrong!! ..... ohhh the engine is not running and its stationary......

[thomson]

Well done!
Did you just remove the box or take the engine /box out together ?

[rathgar]

Did you just remove the box or take the engine /box out together ?

Split the box from the engine and moved the box back and lowered it enough to work on it under the car