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11.25 AAM Rotating on tubes

DavidB

DavidB

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Truck : Uncle Sam's '01 2500 HD gas engine 4x4 Xcab Shortbed. Metal uh, camper shell in bed.

Overload leaf removed for travel. Hyd bumpstops added along with airbags inboard of frame/leaves. Bags and bumps look dead. Limit straps - OK. ORD shackle flip, zero rate, stock leaves sagged a bit.

14FF center section is rotated up about 5-6" at the pinion, maybe 35*. Plug welds are mostly spit out. No traction bar. Driveshaft gone.

Current theory is the constant vertical beating loosens the tubes' press fit in the center section and weakens the plug welds. The airbags putting pressure on the axle so far inboard increses their leverage and probably doesn't help. Trucks get used in sand all the time and they have 25 PSI Off Road on the fender. I suspect they're getting axle wrap/chatter which shock loads the center section and it rotates up.

Anyone got any more ideas? Think we can rotate the housing back down, preload it, weld it, and call it good?
 
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Buddy tried this with his 12 bolt, twice, both times the re-welds started leaking, obviously because it cracked again. Part of the problem is going to be the cast iron housing. He welded the tubes to the housing as best he could as well, didn't help.

There might be a right way to do it, (wait for our welders and industry experts :)) but I would think the dissimilar metals just won't hold a weld well, and the plug welds are present just to keep the press fit tubes from walking out.
 
Tough to save if the casting is fubar. Probably better to find a new axle. Not saying it can't be done but it will continue to be a problematic area. Getting it straight on the repair will be difficult as well.
 
DavidB said:
Truck : Uncle Sam's '01 2500 HD gas engine 4x4 Xcab Shortbed. Metal uh, camper shell in bed.

Overload leaf removed for travel. Hyd bumpstops added along with airbags inboard of frame/leaves. Bags and bumps look dead. Limit straps - OK. ORD shackle flip, zero rate, stock leaves sagged a bit.

14FF center section is rotated up about 5-6" at the pinion, maybe 35*. Plug welds are mostly spit out. No traction bar. Driveshaft gone.

Current theory is the constant vertical beating loosens the tubes' press fit in the center section and weakens the plug welds. The airbags putting pressure on the axle so far inboard increses their leverage and probably doesn't help. Trucks get used in sand all the time and they have 25 PSI Off Road on the fender. I suspect they're getting axle wrap/chatter which shock loads the center section and it rotates up.

Anyone got any more ideas? Think we can rotate the housing back down, preload it, weld it, and call it good?
Click to expand...

So one of the border trucks is having issues and you get to fix it.:D

I would say that given the trouble we had rotating Fox's rotated 14 bolt you will be better off to find a housing and fill it with the guts. I don't think your going to get to hold for long.
 
Get a new housing, swap the guts, then do something like this:

IMG_2291.jpg
 
the beaming load is what causes the problems, the housing is junk if the tubes rotated, becasue the press fit is what carries the load the plug welds don't carry load normaly, even if you weld it the welds will break again. If you are lookign for an upgrade find a 11.5 axle that should be able to take the loading better
 
1979jimmy350 said:
the beaming load is what causes the problems, the housing is junk if the tubes rotated, becasue the press fit is what carries the load the plug welds don't carry load normaly, even if you weld it the welds will break again. If you are lookign for an upgrade find a 11.5 axle that should be able to take the loading better
Click to expand...

It is. :haha:

They said to twist it back around, weld it, and call it good. OK, guys, it's your truck...
 
Got it out, looked at it. It's an AAM. Looks kinda like a Dana 70 or 80 axle. No bolt circle at the pinion like the old 14FF. Mechanic across the street pulled the diff, shafts, hubs, we threw it in the lathe, indicated it, looks pretty straight.
The tubes are loose in the center section though. Twisted them right around with a bar in the spring pad without heating the center section. Aren't the tubes supposed to have 3-5 thou press?
Something else interesting, it wasn't plug welded, it was stud welded. Studs 3/4" with about 3/8" dia. area of penetration - not too good. I think they used the stud welder because the tubes and housing are too dissimilar in makeup. Nickel rod welds to the housing, but not the tube.
They still want us to just plug weld it and put it back, so here it goes. I'm thinking a truss/girdle to fight vertical load and rotation would be a good idea, but it's not my truck.

Well, kinda, since my taxes pay for it, but whatever. :doah:
 
DavidB said:
Got it out, looked at it. It's an AAM. Looks kinda like a Dana 70 or 80 axle. No bolt circle at the pinion like the old 14FF. Mechanic across the street pulled the diff, shafts, hubs, we threw it in the lathe, indicated it, looks pretty straight.
The tubes are loose in the center section though. Twisted them right around with a bar in the spring pad without heating the center section. Aren't the tubes supposed to have 3-5 thou press?
Something else interesting, it wasn't plug welded, it was stud welded. Studs 3/4" with about 3/8" dia. area of penetration - not too good. I think they used the stud welder because the tubes and housing are too dissimilar in makeup. Nickel rod welds to the housing, but not the tube.
They still want us to just plug weld it and put it back, so here it goes. I'm thinking a truss/girdle to fight vertical load and rotation would be a good idea, but it's not my truck.

Well, kinda, since my taxes pay for it, but whatever. :doah:
Click to expand...



well that would be a 11.5 AAM axle, I know the tube bore on the carrier issue all to well. The welds only act as a pin they do not adhere to the carrier its self. That axle came from the plant i was at for this past summer, I have spent many hours getting to the bottom of this problem, we see some of this show up as axle tube leaks through warranty. I would not go through the trouble of welding it, the housing is junk if you have pulled the tubes out, a service axle is only about $800 brand new from the factory. And could you maby get me the codes off the axle tube and PM that info to me, i am kind of interested to see the manufacturing info for the axle, to add to my study of the axle tube bore issue
 
1979jimmy350 said:
well that would be a 11.5 AAM axle, I know the tube bore on the carrier issue all to well. The welds only act as a pin they do not adhere to the carrier its self. That axle came from the plant i was at for this past summer, I have spent many hours getting to the bottom of this problem, we see some of this show up as axle tube leaks through warranty. I would not go through the trouble of welding it, the housing is junk if you have pulled the tubes out, a service axle is only about $800 brand new from the factory. And could you maby get me the codes off the axle tube and PM that info to me, i am kind of interested to see the manufacturing info for the axle, to add to my study of the axle tube bore issue
Click to expand...

Will do. I'd like to know. It's supposedly something special. Ha!

Sure seems like a piece. If we get another housing, is it gonna break?

BTW, we didn't pull the tubes...only rotated them back into position. I think a part of the problem is the studs did not penetrate/stick to the tube like they should have. We are going to drill a small recess in the tube and fill from there to make sure the weld gets a good "bite". Probably run a pass around the tube with nickel too. Supposedly they had this done on the last one and it held up. I think it needs a girdle...
 
Yeah it does sound like you need a truss of some sort. We have broken two 10.5" FF housings in this same matter. I'm honestly surprised it doesn't happen more. I know on a friend of mines truck we are going to run a blue torch fab truss to transfer the rotational torque the pinion sees to the axle tubes, and basically eliminate the stress that the plug welds see on the axle.

I'm curious also to see if the Ni-rod will work on that axle, we welded one up here and it broke again, but i think that may have had something to do with welding it prior to that out on the trail, and then coming home, grinding the weld out and rewelding it with the Ni-Rod.
 
If you get a service housing you should be fine, if you are worried about applying the load closer to the diff its fine, you actually create less of a moment when you apply the forces closer to the center of the axle
 
zcarczar said:
Yeah it does sound like you need a truss of some sort. We have broken two 10.5" FF housings in this same matter. I'm honestly surprised it doesn't happen more. I know on a friend of mines truck we are going to run a blue torch fab truss to transfer the rotational torque the pinion sees to the axle tubes, and basically eliminate the stress that the plug welds see on the axle.

I'm curious also to see if the Ni-rod will work on that axle, we welded one up here and it broke again, but i think that may have had something to do with welding it prior to that out on the trail, and then coming home, grinding the weld out and rewelding it with the Ni-Rod.
Click to expand...

Danny tried welding a piece of mild to the housing with a couple different rods. Some stick to the mild, some stick to the housing. None stick to both well. Will use the nickel as it stuck to the housing well and kinda to the mild. The plug welds will be to the mild so that even if they don't stick to the housing, it can't rotate because the weld is in the way.
 
No luck finding a build code. Where should it be?

It has AXM in a circle stamped all over it.
 
Thanks, I'll look again. I found a website that said later axles just have a tag? I'll look for it too.
 
DavidB said:
Bah, no numbers stamped, guy that pulled the cover is sick, can't find the tag.
Click to expand...

huh thats weird thats theres no numbers, the new axles do not have tags on them when they leave three rivers where they are made only a stamping on the drivers side tube
 
1979jimmy350 said:
huh thats weird thats theres no numbers, the new axles do not have tags on them when they leave three rivers where they are made only a stamping on the drivers side tube
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I cleaned up pretty much the whole thing with wire brush on an air cutoff tool. Maybe under one of the shock mounts? I looked in and around them, nothing.

Maybe my guy has the tag stashed somewhere.
 
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