Worm gearboxon altec boom

Buchanantreeservice

New Member
Location
Johnstown
The other day a piece of tooth broke off my boom gearbox I called altec and 2 days of nightmares and sleepless nights later it wasn't as bad as the first guy told me but the gearbox is around 4000. My bucket is a gmc c7500 topkick with an LRV 50' boom. Altec wants around 20k to come put it in and I do all my own mechanical work on everything but this is a first. My truck didn't come with any kind of manual and I can't really find anything online. I was wondering if anyone has ever replaced one on their own or even had the gearbox rebuilt? Altec doesn't have any refurbished ones that of course would be half that price and worst case I'll buy the part but am not sure what I'm getting into as far as replacing it myself. We really don't have anyone around here that works on buckets we live in a very small area and doesn't seem like it would be a big issue but I don't want to rip it out and get in over my head. If anyone has an info I'd greatly appriciate thank u
 

Jehinten

Well-Known Member
Location
Evansville
The other day a piece of tooth broke off my boom gearbox I called altec and 2 days of nightmares and sleepless nights later it wasn't as bad as the first guy told me but the gearbox is around 4000. My bucket is a gmc c7500 topkick with an LRV 50' boom. Altec wants around 20k to come put it in and I do all my own mechanical work on everything but this is a first. My truck didn't come with any kind of manual and I can't really find anything online. I was wondering if anyone has ever replaced one on their own or even had the gearbox rebuilt? Altec doesn't have any refurbished ones that of course would be half that price and worst case I'll buy the part but am not sure what I'm getting into as far as replacing it myself. We really don't have anyone around here that works on buckets we live in a very small area and doesn't seem like it would be a big issue but I don't want to rip it out and get in over my head. If anyone has an info I'd greatly appriciate thank u
Completely different boom, but I had the rotation gearbox rebuilt on a hi-ranger. Honestly at $4,000 for a new one, your getting a bargain, I was quoted $11,000 for a new gearbox. At that price quote I decided it was worth it for me to remove it myself and crack it open to see what was going on.

Removal wasn't bad, it's just a very heavy part in an awkward position (yours may be completely different) but removing it consisted of taking the hydraulic motor off and 4 mounting bolts. Turns out my bearing were shot and I couldn't get them off so I took it to a local shop who specialize in rebuilding axles and transfer cases. They pressed it apart, did a little machining work, replaced all the bearings and even gave it a coat of paint for $1,100
 

Buchanantreeservice

New Member
Location
Johnstown
Thank you for the reply. Mine isn't the bearings or anything a tooth just broke off on the gear. I think I found one refurbished for half the price or a friend stopped by and knows a guy who can rebuild things like that so I'm going to try both before I make a decision but my concern was taking it off and getting it back on myself I read a post about a main tooth on thr gears and lining them up right ? Like I said my truck didnt come with a manual and altec was supposed to send me one and never did and u can't find anything on line about it so I wasnt sure if it was as simple as getting it off and back on or if it was something more complex lining up gears in a certain pattern or whatnot. But u did take it off and get it back in yourself ?
 

Jehinten

Well-Known Member
Location
Evansville
Thank you for the reply. Mine isn't the bearings or anything a tooth just broke off on the gear. I think I found one refurbished for half the price or a friend stopped by and knows a guy who can rebuild things like that so I'm going to try both before I make a decision but my concern was taking it off and getting it back on myself I read a post about a main tooth on thr gears and lining them up right ? Like I said my truck didnt come with a manual and altec was supposed to send me one and never did and u can't find anything on line about it so I wasnt sure if it was as simple as getting it off and back on or if it was something more complex lining up gears in a certain pattern or whatnot. But u did take it off and get it back in yourself ?
Yes I got mine off and back on. As I mentioned, different makes and models, but my truck was set up as a continuous rotation but has a hydraulic stop switch that stops at a certain point to prevent hoses from kinking.

The switch is independent of the rotation, so for the gearbox it's basically a continuous rotation meaning it didn't matter which tooth of the gearbox interacted with a certain tooth on the boom.

The biggest issue I had, was the weight if the gearbox. I made sure to prop it up with a block of wood and a bottle jack to ensure that it didn't fall onto hydraulic hoses and cause more damage.
 

Winchman

Well-Known Member
How did you find out that the tooth is broken?

Worm gearboxes are built so several teeth on the wheel are always in contact with the worm.
1615052936941.png
You might be able to just keep using it if you take it apart, clean out all the debris, and remove the sharp edges around the break before putting it back together. It may be worthwhile to check/replace the bearings while you've got it apart, though. Chances are good that wear in the bearings let the parts move around, and that put unusual loads on the teeth.

Maybe you could reposition the wheel (if it's bolted in place) so the bad tooth is in a position that's hardly ever or never used.
 

Buchanantreeservice

New Member
Location
Johnstown
How did you find out that the tooth is broken?

Worm gearboxes are built so several teeth on the wheel are always in contact with the worm.
View attachment 74137
You might be able to just keep using it if you take it apart, clean out all the debris, and remove the sharp edges around the break before putting it back together. It may be worthwhile to check/replace the bearings while you've got it apart, though. Chances are good that wear in the bearings let the parts move around, and that put unusual loads on the teeth.

Maybe you could reposition the wheel (if it's bolted in place) so the bad tooth is in a position that's hardly ever or never used.
We were dumping the truck its a forestry model and a piece fell out. Got it back home and looked at it and u can see where a piece of tooth broke off I have the piece that came out its off the little gear on the gearbox the bull gear is ok its just the one tooth I can try to get a picture when I get back
 

Buchanantreeservice

New Member
Location
Johnstown
How did you find out that the tooth is broken?

Worm gearboxes are built so several teeth on the wheel are always in contact with the worm.
View attachment 74137
You might be able to just keep using it if you take it apart, clean out all the debris, and remove the sharp edges around the break before putting it back together. It may be worthwhile to check/replace the bearings while you've got it apart, though. Chances are good that wear in the bearings let the parts move around, and that put unusual loads on the teeth.

Maybe you could reposition the wheel (if it's bolted in place) so the bad tooth is in a position that's hardly ever or never used.
 

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Buchanantreeservice

New Member
Location
Johnstown
He can't get a pic of the inside but that's the outside. Obviously it will need changed but we are a small family owned business and its winter so its slow and thats alot of money for a small company. You can't get the part anywhere but altec we even called the company that makes the gearbox and they said they only have a contract with altec we looked on eBay and none on there that will work but found one on altecs refurbished site thats about half price but they are saying they don't have any in stock. Monday I'm going to make some more calls to see what I can find out. There's an Amish guy that supposidly can redo them not far from us but I was thinking the same just want it to be safe and maybe can get by until the part at least gets here. Worst case he can climb but we use the bed as our dump truck at the moment. We were in the process of buying one until this happened
 

Jehinten

Well-Known Member
Location
Evansville
He can't get a pic of the inside but that's the outside. Obviously it will need changed but we are a small family owned business and its winter so its slow and thats alot of money for a small company. You can't get the part anywhere but altec we even called the company that makes the gearbox and they said they only have a contract with altec we looked on eBay and none on there that will work but found one on altecs refurbished site thats about half price but they are saying they don't have any in stock. Monday I'm going to make some more calls to see what I can find out. There's an Amish guy that supposidly can redo them not far from us but I was thinking the same just want it to be safe and maybe can get by until the part at least gets here. Worst case he can climb but we use the bed as our dump truck at the moment. We were in the process of buying one until this happened
I'd pull it and see about getting the parts made. A machine shop should be able to make it.

Looking at the pics, yours is much easier to get to than mind was. Mine was inside the turret and bolted underneath the ring gear that spun the boom. Yours is mounted ontop, so no risk of dropping it when it gets unbolted. Looks like a fairly easy job to remove and reinstall.

As for using it as is, assuming it will work, it will put extra strain on the other teeth. Eventually those teeth will break as well and will create a dead spot in the rotation.
 

Fivepoints

Well-Known Member
Don't keep using it or you'll be replacing the bull gear as well. You don't need a machine shop, you need a gear shop. They are extremely specialized vs a regular machine shop. Rush gears inc in PA is one that I'm familiar with. Dora gear in dora Alabama is another one that I've used. You'll have to let them quote it but I would expect it to be $1200 to $1800 depending on how complex the rest of it is. Obviously you need to really inspect the bull gear. Be aware there may be shims setting the back lash. Dont loose them.
 

Winchman

Well-Known Member
Oh, I see now. The problem isn't inside the gearbox. It's a tooth on the output gear that drives the bull gear. Jehinten is correct about continuing to use it in this condition.

Any chance of getting a picture of the broken tooth or the piece that fell? Can you get into a position to inspect the both gears? Are you absolutely certain about where the piece came from?
 

Buchanantreeservice

New Member
Location
Johnstown
Pressured washed it and looked in at it you can see where it broke off the gearbox I haven't attempted to pull the part off yet until I get a direct answer or part that I can get for it because if I take it off I can't use the truck period with the boom being swung over and at least I can climb and chip into the truck without using the boom at the moment. We were in the process of getting a new dump truck when this happened so I'm trying to hold off until Monday when I can make some more calls before I go spending a bunch of money on a truck then something unexpected happens with this truck.
 

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Reach

Well-Known Member
Location
Atglen, PA
Pressured washed it and looked in at it you can see where it broke off the gearbox I haven't attempted to pull the part off yet until I get a direct answer or part that I can get for it because if I take it off I can't use the truck period with the boom being swung over and at least I can climb and chip into the truck without using the boom at the moment. We were in the process of getting a new dump truck when this happened so I'm trying to hold off until Monday when I can make some more calls before I go spending a bunch of money on a truck then something unexpected happens with this truck.
I’m sorry to be the bearer of bad news, but that tooth is not part of a worm gear. It’s straight, and a worm gear tooth would be curved. It looks to me like it is a tooth off the ring gear/bull gear on the boom.
 

Buchanantreeservice

New Member
Location
Johnstown
Its the gear at the bottom of the gearbox that turns the bull gear altec told me its a worm gearbox and thats about all they want to tell you but u can see where it broke off I'm going to go out later and try to take it off enough to get other pictures
 

Buchanantreeservice

New Member
Location
Johnstown
I’m sorry to be the bearer of bad news, but that tooth is not part of a worm gear. It’s straight, and a worm gear tooth would be curved. It looks to me like it is a tooth off the ring gear/bull gear on the boom.
Posted it in the wrong spot but its the big gear on the gearbox that turns the bull gear idk the technical name for it all altec would tell me is its a worm gearbox
 

Jehinten

Well-Known Member
Location
Evansville
Sounds like you've seen the break, but just can't get a pic while it's assembled? I'm hoping the gear it matches to is in good shape and it'll be an easy repair. Attached is the picture of my gear box. This truck is out of commission and I still have the gear box. It's highly unlikely that it'll be the same gear, but I have one available if it is.
 

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