40C popping out of gear

krusty · Post by **krusty** » Sun Mar 23, 2014 8:41 am

Hi gang,

Hope all is well. Late last fall my crawler started to pop out of gear and with winter approaching I parked it not wanting to spend any effort on it till spring. Well hopefully another week will bring warmer temps and I wanted to address the issue. Not sure what to consider on it other then pulling the tranny out and stripping it down for an inspection and rebuild. Any guidance would be appreciated!

krusty,

JimAnderson · Post by **JimAnderson** » Sun Mar 23, 2014 9:17 am

You can get some idea of the problem just by pulling the shifter cover.
You didn't say what gear your'e in when it pops out but I suspect second.
These old crawlers get shifted between 2nd and reverse constantly and
the operater doesnt wait for the machine to stop.This results in the
grinding away of the teeth.If you look at which set of mating teeth are
chewed you might see that there very little left to mesh.If bad enough
then they ramp out of mesh under load.If this is your problem then it can only fixed by replacing the input shaft and the second gear.
It might also be caused by a sloppy shifter fork but I would supect gear damage is more likely the cause.Luck,JimAnderson

krusty · Post by **krusty** » Sun Mar 23, 2014 10:15 am

Jim,

Thx for the input. Ironically I am one of those guys who waits for the gears to stop during a shift! Though as you say popping the shift cover would be quick to see what is in there. I do not recall what gear it is popping out of but can find out pretty quick once I take it for a little spin.

K,

JimAnderson · Post by **JimAnderson** » Sun Mar 23, 2014 11:22 am

K,
If you find significant internal gear damage don't waste time looking
for 40c internals.Most old crawler transmissions will likely have the same
damaged parts.Look instead for transmision internals from a wheel tractor.They tend not to be shuttle shifted unless equiped with a loader.
They also are more plentiful and except for the ring carrier have the same internal parts. Luck ,JimAnderson

Post by **Lavoy** » Sun Mar 23, 2014 2:09 pm

Not all of them, crawlers have some different gears, learned that one the hard way once. Took a long time to stuff that input shaft in, and once in, locked up solid. THEN I read the parts book, DOH!

Lavoy

JimAnderson · Post by **JimAnderson** » Sun Mar 23, 2014 5:12 pm

Lavoy,
You are correct about crawler specific trans parts.As much as I push
using the parts manuals I missed some of the info.With that said I still
think that wheel tractor transmissions make good donors when the different model and serial breaks show cross use to crawlers.I usually
use all of the parts that come out of a donor and I hope that is what has kept me from having the surprise you found.Man I hate taking anything
apart that I just put together.Luck,JimAnderson

krusty · Post by **krusty** » Thu Apr 03, 2014 12:41 pm

The sun is shining so I popped the shifter off the tranny. The forks are fine but noticed the top right shaft has a bearing at the front that is toast. Oh well I pretty much knew I was going to have to tear the darn rear end out to fix it and might as well start this weekend.

Thanks gang!

krusty · Post by **krusty** » Thu Apr 10, 2014 12:15 pm

Could not find my CDROM manual for the life of me and realized I copied the PDF file to a backup hard drive thankfully.

Since it is the front bearing on the output shaft that is toast....I plan to take the engine out, then the clutch housing and change the bearing with the back ass still intact. Having never gone into the tranny is this a reasonable approach?

Post by **Lavoy** » Thu Apr 10, 2014 1:28 pm

Should work, but I would look at the input shaft bearing and seal while I was there too. Also thoroughly clean out the oil galley that runs down the LH side of the tranny case, and both passages in the front of the tranny case. This is where the lube comes from that lubes both the input and output shaft bearings. If the gears have even been ground in the tranny, it throws metal filings into the galley and washed them into the front bearings. This might be the reason for your failure.
Lavoy

krusty · Post by **krusty** » Tue Jul 22, 2014 6:44 pm

How is that for procrastination! Finally got around to getting at this. Took the engine out, then the bellhousing assembly and the bearing or what was left of it was easy to remove. Looks like there was no cotter pin in the nut and the nut eventually loosened allowing the bearing to play. The bearing cover was shot and will get another but hope to be moving dirt again by this weekend!

The small yard projects are piling up

krusty · Post by **krusty** » Mon May 25, 2015 10:38 am

Well that was depressing. I spent the weekend finally tearing apart my crawler to replace the chipped gears. Imagine the surprise when I opened up the back of the tranny to see the ring and pinion shredded.

*sigh*

What can you do? At least it was easy enough to get all apart.

The manual says the ring has 32 and pinion has 7 teeth. Mine has 41 and 9. Other 40 tractors have an option for 41 and 8 teeth. Any wisdom on whether the carrier for the ring is the same between all of these permutations? Do I just need to look for a matched pair?

The good news I guess is that this will be the only part of the machine I have left to tinker with. There are a couple serious JD collectors local to me who are always asking to buy it from me, and after seeing that ring shredded I almost called them to come get it

Krusty,

Post by **Lavoy** » Mon May 25, 2015 7:42 pm

Don't use 41 and 8, that is for wheel tractors.
Lavoy

krusty · Post by **krusty** » Thu Jul 28, 2016 9:12 pm

Wow maybe I should be ashamed but I finally found a local to me donor tranny at a reasonable price. Got it all back together with some new bearings and it is running smooth! Talk about a long term project and the neighbors were wondering if it would ever run again.

I find now that the gears grind when I want to put it into gear. I press in the clutch, wait 20 seconds and still try and the darn insides of the tranny are still spinning. I reused the same clutch, throwout bearing and pilot bearing. Did not think I had any need to inspect them before putting it back together.

Fortunately I have spent enough hours on this little project to be able to pop the engine off pretty darn quick!

What should I be looking for? I am going to guess it is the pilot bearing that is toast and stiff which is driving the input shaft to the tranny.

2nd guess would be the throwout bearing but I dont physically see how that could drive the shaft. As they are really not connected.

3rd would be the clutch not adjusted properly but think that is the least of the potential items since when I stop in gear, with clutch pressed in, there is plenty of travel once the clutch has disengaged and the pedal is not bottoming out.

Any wisdom appreciated.

Post by **Lavoy** » Fri Jul 29, 2016 9:00 am

Pilot bearing is one possibility, other is if the clutch disc is in backwards. On some discs, the hub will run against the flywheel and keep the disc spinning no matter what you do with the clutch pedal.
Lavoy

krusty · Post by **krusty** » Mon Aug 01, 2016 6:03 pm

Tore it all apart today.

Throwout bearing is fine. Pilot bearing is fine. Has to adjust the clutch fingers as they were high, but I would have expected low. At least they were all high at the same level.

Clutch disc is in good shape. The plates has a slight oxidation to them in the pattern of the clutch disk for sitting so long I guess so I removed the oxide layer on the plate. That is the only thing I could see making it stick but would have thought with the significant clutch travel the disc would have cleared any friction on the pressure plate.

Oh and one more noticeable tidbit....the splines between the shaft and the clutch disc has slight oxidation too but now it is all lubed up and able to move freely if needed. Will put the engine back in tomorrow and find out!

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