Pinion chips, how to fix it?

sharksanddanger

sharksanddanger

Well-Known Member
Joined
Apr 18, 2005
Location
Reidsville
One of the pinions in my axles has 3 pretty decent chips in the gears, they are pretty hard to come by so finding another one thus far has not been an option unless I want to take a trip to germany or buy another axle.
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ai197.photobucket.com_albums_aa63_Frontier2k1_Frontier_DSC00909.jpg

ai197.photobucket.com_albums_aa63_Frontier2k1_Frontier_DSC00910.jpg


I was wondering if I TIG'd the spots up then sanded them down real smooth and got them heat/cryo treated if that would be a good idea. Anywhere know anyone that can cryo or heat treat the pinion gear or how expensive it would be?

Maybe one of ya'll has another option, let me know what you think.

Thanks!
 
I hate to say it man, but I think you're boned on that one. I understand the repair that you're proposing, but I just don't see any conceivable way that you could possibly machine it back down with a sufficient degree of precision to make it work. At a bare minimum it would be loud, and more probably it would grenade in short order. Good luck finding a replacement ring and pinion.
 
Is it a Mog axle? Their was some people on the board running those may they got a partial unit or something to part out? Anyways, what kind is it maysomebodies got the chunk of "Gold your needing. Good luck.
 
Roughshod said:
I hate to say it man, but I think you're boned on that one. I understand the repair that you're proposing, but I just don't see any conceivable way that you could possibly machine it back down with a sufficient degree of precision to make it work. At a bare minimum it would be loud, and more probably it would grenade in short order. Good luck finding a replacement ring and pinion.
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Well, the chips are on the inside of the teeth, I would think I can just tig up the low spots and sand it real smooth, I have the edge there to make sure there is no base metal reduction after I start sanding.

I know that a new r and p would be best but I can't find one and if I could I'm sure the price tag would be more than another axle.

Anyone know what may have caused the chips? It almost looks like something got inbetween the gears and chipped the pinion, the ring gear looks just fine. It doesn't look like poor setup would cause the chips in those locations.
 
WARRIORWELDING said:
Is it a Mog axle? Their was some people on the board running those may they got a partial unit or something to part out? Anyways, what kind is it maysomebodies got the chunk of "Gold your needing. Good luck.
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Yeah, its a mog 406. If I had the 404 I could have found it but the 406 is pretty tricky to find.
 
sharksanddanger said:
Well, the chips are on the inside of the teeth, I would think I can just tig up the low spots and sand it real smooth, I have the edge there to make sure there is no base metal reduction after I start sanding.
I know that a new r and p would be best but I can't find one and if I could I'm sure the price tag would be more than another axle.
Anyone know what may have caused the chips? It almost looks like something got inbetween the gears and chipped the pinion, the ring gear looks just fine. It doesn't look like poor setup would cause the chips in those locations.
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"Inside of the teeth"? I don't follow you. Which side of the tooth the damage is on is irrelevant, because one side of the tooth is under load when your on the gas, and the other side of the tooth is under load when your coasting, therefore there is no unimportant side of the tooth.

As for using the existing portion of the tooth as a sanding guide, I still don't think you could make the required curve without removing part of the good portion of the tooth, which would of course screw you over.

But don't let me talk you out of it, try it for yourself. Just try it first on a junk pinion to make sure that your methodology is sound. Trust me, I hope I'm wrong and that you can make it work, but you definitely don't want to screw up the real pinion while honing your technique. Surely someone has an old take out pinion they would give you to practice on? Good luck.
 
Roughshod said:
"Inside of the teeth"? I don't follow you. Which side of the tooth the damage is on is irrelevant, because one side of the tooth is under load when your on the gas, and the other side of the tooth is under load when your coasting, therefore there is no unimportant side of the tooth.

As for using the existing portion of the tooth as a sanding guide, I still don't think you could make the required curve without removing part of the good portion of the tooth, which would of course screw you over.

But don't let me talk you out of it, try it for yourself. Just try it first on a junk pinion to make sure that your methodology is sound. Trust me, I hope I'm wrong and that you can make it work, but you definitely don't want to screw up the real pinion while honing your technique. Surely someone has an old take out pinion they would give you to practice on? Good luck.
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I appreciate your advice and you're probably right but there is no spare pinion. The "real pinion" is the one in the picture so it would be screwed up one way or another, I only have two, one for the front that is in good shape and one for that back above in the pictures. I understand what you're saying and I am doubtful that it will be a sound way to do it but unless you have or know of somewhere to find a 406 r&p I don't have another option.
 
sharksanddanger said:
I appreciate your advice and you're probably right but there is no spare pinion. The "real pinion" is the one in the picture so it would be screwed up one way or another, I only have two, one for the front that is in good shape and one for that back above in the pictures. I understand what you're saying and I am doubtful that it will be a sound way to do it but unless you have or know of somewhere to find a 406 r&p I don't have another option.
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Nobody says that you have to practice on a mog pinion. ANY scrap pinion will do for practice. Like I said, you just don't want to destroy your only pinion with a repair that you don't know will work.
 
try this guy...
name is matthew
860-672-4273
hes a friend of a friend, up in new england but a few months ago he had 4 406s he was parting. I know my buddy was saying he was pissed because one rear had been fubared from some wreck, but maybe that R&P is good....no idea
 
If you decide to weld on it, make sure you anneal it first. This is best done in A temperature controlled furnace. It could however be done with A rosebud torch, & A small pile of fire-brick. After you weld it with the proper filler metal, be sure to have it re-heat treated. Also try to get it rockwell tested, so they'll know what hardness it needs. I would just take it to what ever heat treater, you will be using, & get them to normalize it.
 
SkyHiK5 said:
try this guy...
name is matthew
860-672-4273
hes a friend of a friend, up in new england but a few months ago he had 4 406s he was parting. I know my buddy was saying he was pissed because one rear had been fubared from some wreck, but maybe that R&P is good....no idea
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I just gave him a call but all the axle parts are long gone he said. Thanks for the heads up though.

Chris(snappy) gave me a link to a place I'm going to try to see if they have a r&p.
 
buckshot500 said:
If you decide to weld on it, make sure you anneal it first. This is best done in A temperature controlled furnace. It could however be done with A rosebud torch, & A small pile of fire-brick. After you weld it with the proper filler metal, be sure to have it re-heat treated. Also try to get it rockwell tested, so they'll know what hardness it needs. I would just take it to what ever heat treater, you will be using, & get them to normalize it.
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Thanks for the good info. Hopefully I won't have to weld it but we'll see.
 
sharksanddanger said:
I just gave him a call but all the axle parts are long gone he said. Thanks for the heads up though.
Chris(snappy) gave me a link to a place I'm going to try to see if they have a r&p.
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cool, sorry it didnt work out...
 
I havent set up gears in a Mog axle before but Im assuming it would be relatively the same procedure as an american axle. If there was no metal pieces in the oil when you drained the diff that could have caused the tooth damage, I would venture to say that the carrier preload wasnt set right. If it is too little the carrier can move away from the pinion under load (ie squirm or deflect) which increases backlash. This will cause insufficent tooth contact resulting in chipping and breaking of gear teeth. Full time gear heads chime in here if I'm wrong..........
 
thats not from deflection, why did you pull the gears apart.

I guess what is trying to be accomplished here, the chips will ultimatley eat the gears up. but if it is a strength concern due to the chips, i guess i would ask if by filling in the chips will it strengthen the pinion or will it actually weaken it. When filing it in you are not going to be able to get the same curveture of orginal so its going to cause a funky pattern/ wear int hose areas, I would sand file sand down the the rough edges on the chips and put it back together, it will probably be fine for offorad usage. If road noise and performance is your concern than i think you fubared any way you look at it. if the edges are filed down all that is going to happen is your giong to have lees contact surface but it will roll right into the ring gear and not cause any other additional damage.
 
snappy said:
Cperry be the man and find the man a set of gears.......
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X2, get me some! I'm going to call swiss army vehicles tomorrow and I may have a lead on one out west but we'll see. I'm keeping my fingers crossed.

I pulled the pinion out just have a look at it. The axles need some new seals and such and that was one of the first things I wanted to look at. I was thinking that something had to have gotten inbetween the ring gear and pinion, its just some weird chips, every single gear break I have ever seen have been actual teeth missing or at least missing at the edge, these are neither.

I'm not exactly sure how these gears go together for setup but the bearing races are in each axle tube and the tubes unbolt from the center but the carrier is only held in by the axle tubes. You can see the design of the outside from this picture if you're unfamiliar with a 406.
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It seems like it would be an awful lot of work to have to disassemble the whole axle each time you need to add a shim to the carrier, I read somewhere that the only adjustment was the pinion depth but that doesn't make a lot of sense, it seems like it'd be pretty hard to get that thing spot on with only being able to adjust the pinion depth.

Just for fun this is a picture of the mog pinion next to a d44 pinion.

ai197.photobucket.com_albums_aa63_Frontier2k1_Frontier_DSC00912.jpg
 
Your very last picture seems to show alittle blue color beside the damage. Hard to tell but if it is, I'd guess it was a heat issue and gauling was the culprit. Smoothing them a bit and running them is what I'd do. No loss of any heat treat or hardness and the damage doesn't appear deep enough to weeken them alot. If you really can't adjust preload how is backlash set. To little backlash and or to deep a mesh causes heat, I've seen gauling on gears and it looks alot like this instead of chips from sudden shocks or uneven loads.
 
WARRIORWELDING said:
Your very last picture seems to show alittle blue color beside the damage. Hard to tell but if it is, I'd guess it was a heat issue and gauling was the culprit. Smoothing them a bit and running them is what I'd do. No loss of any heat treat or hardness and the damage doesn't appear deep enough to weeken them alot. If you really can't adjust preload how is backlash set. To little backlash and or to deep a mesh causes heat, I've seen gauling on gears and it looks alot like this instead of chips from sudden shocks or uneven loads.
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If you talking about the picture of the comparison between the mog and the d44 that pinion is actually the one that is not chipped.

As goes for the gear setup I have no idea, I'll check it out as I get the axles tore down some more. They must be something I'm missing around the carrier.
 
Run it as is. Those are 4 ton axles. The pinion is ridiculous sized already and sees half the load of a non reduction axle pinion. I would put money on you breaking your portal boxes/gears long before having problems with that.
 
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