L3750 Rear axle shaft Removal

[Bigtater91]

Hello All,

This is my first post so hopefully this is the right place to ask. I have a new to me L3750 4wd. I am trying to replace the rear axle seals. They are leaking hydraulic/transmission fluid when it is sitting.

To remove the rear axle shafts do you just pull the axle cover (I.e. cover with 4 bolts and the seal) and hammer the axle out? Or do you have to pull the gear case and undo a axle clip or re

 

[kubotafreak]

Remove the axle case, there is a bolt and carrier plate. Then the outer carrier bearing/axle seal nut.

 

[Bigtater91]

Kubotafreak, thanks for the help. Unfortunately, like an idiot, I already tried to beat the axle out a bit before this. Hopefully, no damage was done. Will post back once I get it off.

 

[rbargeron]

Hi Bigtater91 Here's a blow up of the seal area from a WSM.
The book says take the axle housing off the tractor. The planetary gear carrier comes with it, held on by a snap ring. Then the axle comes out

To avoid all this, sometimes a "string packing" works wonders on low-pressure, low speed shaft leaks. Wrap a couple dozen turns of twine around axle so it helps plug the gap. Once oil-soaked it may stop dripping.

 

[Bigtater91]

Rbargeron, i was looking at the WSM (albeit seems different from yours) prior to this and my copy says the same. I did get the outer bearing to pop out, but is there an inner bearing? At this point, I think I may have to pull the case to get at the backside of the axle to beat it out. Just because if there is no retainer it really does seem seized. Here is a picture of the outer bearing I’m referencing:

 

[rbargeron]

Rbargeron, i was looking at the WSM (albeit seems different from yours) prior to this and my copy says the same. I did get the outer bearing to pop out, but is there an inner bearing? At this point, I think I may have to pull the case to get at the backside of the axle to beat it out. Just because if there is no retainer it really does seem seized. Here is a picture of the outer bearing I’m referencing:

That inner snap ring holding the axle in the carrier is hard to see in the drawing but its there.
I'd shine up the axle and try the rope packing idea. Its a slow-turning seal so may last a long time.

 

[kubotafreak]

Is a 5450 the same part? When I looked up the parts diagram the axle has a bolt and star shaped washer internal against the inner carrier bearing.

 

[rbargeron]

Edit: Kubotafreak is right the L3750 has a different style carrier retainer - a 3-legged star bolted to the end of the axle.

Either way the retainer has to be removed to get the axle out of the carrier and housing.

I looked up the retainer's where-used - and the l48's carrier uses it too.

 

[kubotafreak]

Im always used to having the more involved setup... im never that lucky...

Bigtator, use brake clean & Loctite on that bolt. It is one you really don't want coming off.

 

[Bigtater91]

Thanks everyone for the help up to this point! So I did get the axle out. You do have to pull the case, and remove a three sided retainer.

It seems now that I have gone from the frying pan to the fire. So the enthusiastic beating I gave the axle the other day resulted in the inner bearing (no. 50) becoming unseated. Two small tabs that retain the bearing and that are part of the casting are broken off. Otherwise the case is okay. The bearing is now stuck in the internal cavity of the case. It seems that it will have to be pressed back into position. Anyone done this before?

My real concern now is if the bearing will become unseated during operation due to these tabs being broken. The inner bearing butts up against washer no. 40 which is seated on the axle below the splines. It seems this washer would compensate for the lack of those tabs. It seems like the washer will keep the bearing from pushing out, but I'd rather ask than break more stuff.

I will definitely try this string packing on the other side to avoid this headache.

 

[kubotafreak]

Pictures please

 

[rbargeron]

A new inner bearing for $31 is in order (once it has taken that much force) - but one tab will likely locate the inner bearing ok - the outer bearing takes the side loads. Clean and inspect the case well - be sure there are no cracks around the broken tabs. If the case is in doubt there's one on eBay and another at Wenger's - each around $200 (probably have good bearings in them). Best luck, Dick B

 

[Bigtater91]

I did in fact manage to break both tabs although the bearing looks ok from what I can tell with it being stuck in the axle tube portion. What an idiot I am. Will take some pictures tomorrow once I am off work. Thanks for the lead on the used cases. I will go that route if the pictures show it as unsalvageable to you guys.

 

[kubotafreak]

Everything is usually salvageable. If the casting bosses(tabs) broke of the inner half, degrease it real well and take it to someone who can tig two silicone bronze tabs on it. Grind it back flat and you should be good as new. Like rbargeron said, the outer cap is the main source of constraint for the axle from coming coming out.

Just had another idea, and this one is proven since I've seen them built this way. You can take a sleeve of tube just larger than the axle shaft. Cut it nice and flat so it mates between the two inner bearing races, or in your case the bearing nut and the inner bearing race.

You could also grind a groove for an external snap ring to restrain the inner race of the inner carrier bearing...

 

[rbargeron]

A piece of tubing as a spacer is a great idea. It can ride with the axle, taking the place of the tabs. Exhaust tubing cut square on a lathe. No need for tabs. Nice.

(typical axle pics here.)

 

[Bigtater91]

So here are some photos of the carnage. I like the tubing idea, though I am thinking the washer is already on the shaft for this reason. I still have to knock the bearing out of the case. I can’t push it back through the planetary side of the case or the axle tube side. It seems like I will have to use a press to get it out. Until that happens I won’t really know if the tubing would work, because I would need to get the bearing out of the case to test fit it.

 

[rbargeron]

I think the bearing should be sacrificed by cutting through the outside ring with an abrasive disk.

Jammed in where it is, its putting stress into the axle case - and the case is no longer supported by being bolted to its mating parts. It would be a shame to crack the case trying to get a $31 bearing out that's likely damaged anyway. I wouldn't use a torch - too much heat. I'd use an angle grinder with a cutoff wheel to chop it up.

 

[kubotafreak]

As long as the inner rides atop that spacer, you should be fine. That will be enough to hold that bearing, along with the tri-lobe retainer.(This was my other fix as a snap ring) That stuck bearing should be removed toward the brake side. It would be a shame to get it in the tube of the housing and it not come out the end because it is too big. I guess one positive about the receiving flange being marred up, is the friction fit will be tighter. Relief cutting the outer race to remove rollers would be a good method.

I just noticed all your chicken marks around the hub... You were determined...

 

[Bigtater91]

Well the book did say hammer it out... I did take that a little to literal haha. The sad thing is that I am not the first person to beat it like it owed me money. You probably can't see it in the pictures, but there is a bunch of dents that were there from the last guy hammering on it.

Anyways the bearing is already stuck in the tube. I will cut it out. A new bearing will definitely have to be put in via hydraulic press from the brake side. Once all that happens I will test fit it on the bench and report back.

When reassembling the rear axle nut my manual states to torque it between 289ft lbs and 506ft lbs. That seems like quite the range. I assume that they intend for you to torque it similar to a wheel bearing? Adjusting the torque in accordance with the feel/smoothness and of the bearing, whilst lining up the stake? Can someone offer advice on this before I break something else with my hammer?

Thanks again fellas!

 

[kubotafreak]

Well the book did say hammer it out... I did take that a little to literal haha. The sad thing is that I am not the first person to beat it like it owed me money. You probably can't see it in the pictures, but there is a bunch of dents that were there from the last guy hammering on it.

Anyways the bearing is already stuck in the tube. I will cut it out. A new bearing will definitely have to be put in via hydraulic press from the brake side. Once all that happens I will test fit it on the bench and report back.

When reassembling the rear axle nut my manual states to torque it between 289ft lbs and 506ft lbs. That seems like quite the range. I assume that they intend for you to torque it similar to a wheel bearing? Adjusting the torque in accordance with the feel/smoothness and of the bearing, whilst lining up the stake? Can someone offer advice on this before I break something else with my hammer?

Thanks again fellas!

Id gauge the nut torque of what it takes to get apart. Should take about 3/4 to put back which hopefully falls in that range(which seems really high). I do suggest bolting the axle to the rim so you have something to hold/stand on. The translation I assume means to seat the bearing then torque it. Since it is pressing the assembly together. Loctite is your friend

Also pay attention to that seal when you get it apart. I believe it is a unitized seal/wear ring.