Well I was changing my oil this past Sunday and like always I crawl around under the truck checking everything. Well when I got to the rear driveshaft on the front yoke there was a 3inch crack going same way as the weld.. This crack isn't on the side of the weld like most cracks.. It is dead center of the weld.. I talked to the stealer yesterday and he knows that I've got a DPF delete and told me I would have to tIe my truck back to stock completely before he could fix it... So a buddy of mine owns a welding shop and I tig welding it balancing it for me..

The stealer said to put your DPF back on before he would fix the drive shaft?

WTF does the DPF have to do with the drive shaft. What a A$$!

Yeah we had a stealership one town over pretty much screw every GM coustomer/dealer last year... No matter what the year or milage or modifications to the vehichle they would do the work as warranty work so GM shut them down completely so now in central ky a GM rep goes to every dealership anytime there is a warranty claim and inspects the truck... So yeah it sucks pretty bad...

Well I was changing my oil this past Sunday and like always I crawl around under the truck checking everything. Well when I got to the rear driveshaft on the front yoke there was a 3inch crack going same way as the weld.. This crack isn't on the side of the weld like most cracks.. It is dead center of the weld.. I talked to the stealer yesterday and he knows that I've got a DPF delete and told me I would have to tIe my truck back to stock completely before he could fix it... So a buddy of mine owns a welding shop and I tig welding it balancing it for me..


Is it an aluminum driveshaft? Typically shafts that have been tig welded ( steel or aluminum) end up crooked, the much slower heating and filling process usually warps them. Not tryin to wiz in your corn flakes, just throwin it out there.

yes it's aluminum.. Everyone that I have talked to said with it not being a brand new shaft that the best way to weld it would be tig.. They said that if it was brand new then they would use a spool gun on it.. Well mig..

Is it an aluminum driveshaft? Typically shafts that have been tig welded ( steel or aluminum) end up crooked, the much slower heating and filling process usually warps them. Not tryin to wiz in your corn flakes, just throwin it out there.

In my experience TIG welding is a "cool" process and gives the least amount of warping. I guess if you only welded the area where the crack was, it could definitely warp.

Anyways, I would be MUCH more concerned about the strength of the aluminum now. Welding aluminum removes it's heat treating process that gives it strength. Weld a piece of 6061 with a T6 heat treat (say 61,000 psi strength), and it goes down to a T2 heat treat strength (31,000 psi) numbers from memory :o:. Only the area that was heated by the welding process will weaken like this. The ONLY way to get the strength back is to have it heat treated.

Now, I'm pretty damn sure your aluminum drive shaft is not made form 6061-T6, but my point is, whatever grade of aluminum it is made out of, that area has now completely lost it's strength.

Oh, and that is bull what the dealer told you... the welds should NEVER break or crack before the rest of the drive shaft, they are supposed to be the strongest point. IF the additional power did in fact cause the drive shaft to fail, the tubing would have failed, but it didn't, so the weld is a factory defect, end of story.

Take the shaft out and bring it to the stealer. Tell them that you are afraid to drive it as it sure looks like it will break. Maybe that would work?

jb

yes it's aluminum.. Everyone that I have talked to said with it not being a brand new shaft that the best way to weld it would be tig.. They said that if it was brand new then they would use a spool gun on it.. Well mig..

The best way to weld it would have been to cut the old weld out, make sure its trued up and re weld, in which case spool gun or alum mig would be the weapon of choice. But hey man, if your truck is alright and you didnt feel a vibration before im sure it will feel just fine after.

In my experience TIG welding is a "cool" process and gives the least amount of warping. I guess if you only welded the area where the crack was, it could definitely warp.

Normally i would agree with you, but its not necessarily going to warp because of excessive heat, but more because of the the slow travel and inability to quickly lay another pass 180* opposite to counteract the pull. By the time your done with your tig bead, the begining of the bead is probably already cooled considerably and thusly already started to shrink a bit and pull. Butt two pieces of plate togther, tig one side, then flip it over and tig the other side. Now take to more pieces and do the exact same thing with a mig welder. Now which piece has less signs of warping at the joint where you bonded the two pieces together?

Anyways, I would be MUCH more concerned about the strength of the aluminum now. Welding aluminum removes it's heat treating process that gives it strength. Weld a piece of 6061 with a T6 heat treat (say 61,000 psi strength), and it goes down to a T2 heat treat strength (31,000 psi) numbers from memory :o:. Only the area that was heated by the welding process will weaken like this. The ONLY way to get the strength back is to have it heat treated.



Now, I'm pretty damn sure your aluminum drive shaft is not made form 6061-T6, but my point is, whatever grade of aluminum it is made out of, that area has now completely lost it's strength.
Oh, and that is bull what the dealer told you... the welds should NEVER break or crack before the rest of the drive shaft, they are supposed to be the strongest point. IF the additional power did in fact cause the drive shaft to fail, the tubing would have failed, but it didn't, so the weld is a factory defect, end of story.

If i remember right, aluminum driveshaft tubing is T-3, which correct me if im wrong can be heated and cooled without losing any of its original strength. Having said that, i HIGHLY doubt it was heat treated after it was welded together at the factory, simply because heat treating has a tendency to shrink holes, so the holes in the weld yokes would have to either be re machined or not machined until after.

But the weld is still hands down a factory defect and i would have really rode the dealership hard to replace it.

If i remember right, aluminum driveshaft tubing is T-3, which correct me if im wrong can be heated and cooled without losing any of its original strength. Having said that, i HIGHLY doubt it was heat treated after it was welded together at the factory, simply because heat treating has a tendency to shrink holes, so the holes in the weld yokes would have to either be re machined or not machined until after.

But the weld is still hands down a factory defect and i would have really rode the dealership hard to replace it.

I'll jump onto your side of the fence about the warping issue. :D

I had NO IDEA what kind of aluminum factory drive shafts used. I worked in a factory (UBE) that makes wheels for high end cars like Bentley, BMW, ect. They heat treat the rims after all machine work is done. I don't know if they do this to drive shafts or not, I guess only way to know for sure is to ask someone who works/worked in one of GM's factories.

I really appreciate all the info guys... Well it only cost me $50 to get it fixed right.. Rewelded balanced and everything.. But it wasn't cheap work.. The guy that done it owed me a favor.. But he said it was a factory defect because in the center of the 3 inch crack he said there was an empty pocket which caused the weak spot.. But he grinded all of the weld out that had the crack and drilled a hole on each end to stop the crack then rewelded it.. Then he checked the balance on it...

Well come to find out this afternoon 2 of the 3 stealerships I called are 2 of 1200 GM stealerships being shut down and that's why they wouldn't work with me and the 3rd one I called I've never dealt with before and everyone I've talked to said that if you take your truck in to them it has to be BONE STOCK and if they notice any type of mod they void your warranty... But as far as the 2 being shut down... They were the 2 closest to me so now I'll have to drive at least 30-45mins to get to a GM stealer...

I'll jump onto your side of the fence about the warping issue. :D

I had NO IDEA what kind of aluminum factory drive shafts used. I worked in a factory (UBE) that makes wheels for high end cars like Bentley, BMW, ect. They heat treat the rims after all machine work is done. I don't know if they do this to drive shafts or not, I guess only way to know for sure is to ask someone who works/worked in one of GM's factories.

Im assuming since you can buy the weld yokes and parts to build aluminum driveshafts they are not heat treated after being welded, but im just speculating based on what i know.

I really appreciate all the info guys... Well it only cost me $50 to get it fixed right.. Rewelded balanced and everything.. But it wasn't cheap work.. The guy that done it owed me a favor.. But he said it was a factory defect because in the center of the 3 inch crack he said there was an empty pocket which caused the weak spot.. But he grinded all of the weld out that had the crack and drilled a hole on each end to stop the crack then rewelded it.. Then he checked the balance on it...

Well come to find out this afternoon 2 of the 3 stealerships I called are 2 of 1200 GM stealerships being shut down and that's why they wouldn't work with me and the 3rd one I called I've never dealt with before and everyone I've talked to said that if you take your truck in to them it has to be BONE STOCK and if they notice any type of mod they void your warranty... But as far as the 2 being shut down... They were the 2 closest to me so now I'll have to drive at least 30-45mins to get to a GM stealer...


Some times it pays to spend a couple bucks and avoid the dealer, i know the feeling. My family runs a local driveline and machine shop and we do quite a bit for different dealers in the area. My dads 05 2500hd needed a u-joint and it was still under warranty, but at that time the lube tech they had doing most of the u-joints was really good at beating a dent in the tube while changing joints. In fact i had straightened and balanced a couple of his jobs at the dealers expense. So we decided it would be easier to just grab a couple of joints off the shelf and do dads truck in house. We figured the little bit of time and minimal cost of two joints was worth having a dent free tube.

Im assuming since you can buy the weld yokes and parts to build aluminum driveshafts they are not heat treated after being welded, but im just speculating based on what i know.




Some times it pays to spend a couple bucks and avoid the dealer, i know the feeling. My family runs a local driveline and machine shop and we do quite a bit for different dealers in the area. My dads 05 2500hd needed a u-joint and it was still under warranty, but at that time the lube tech they had doing most of the u-joints was really good at beating a dent in the tube while changing joints. In fact i had straightened and balanced a couple of his jobs at the dealers expense. So we decided it would be easier to just grab a couple of joints off the shelf and do dads truck in house. We figured the little bit of time and minimal cost of two joints was worth having a dent free tube.

Yeah, I was thinking about the yokes you can buy too, so I think the question about heat treating is answered. :)

You know all the ins and outs already it seems... hehehe
Were you just testing to see if I was a BSer? :p:

Haha, it's all good. :beerchug:

Yeah, I was thinking about the yokes you can buy too, so I think the question about heat treating is answered. :)

You know all the ins and outs already it seems... hehehe
Were you just testing to see if I was a BSer? :p:

Haha, it's all good. :beerchug:


No need to test if you were a bs er, although i think i put my foot in my mouth seeing as how im starting to think aluminum driveshaft tubing is T6 series. :rolleyes:

my 06 2500 crewcab long box is a steel 2 peice shaft

5356 filler will work fine. You

5356 filler is fine. You must use 100% pure Argon purge/shield gas around 30 cfh. You will need around 170 amps AC with moderate high freq and a 2% Thoriated tungsten with the end balled to no more than 1/8 inch diameter. Excavate ahead and beyond the crack completely so the prepped area is smoothly polished so it can be cleaned to perfection. It is almost impossible to overclean Aluminum. CAREFULLY use acetone to clean the weld area and let evaporate COMPLETELY!!!! You can slowly preheat the workpiece before welding with a torch but only a few hundred degrees or the contaminants in the atmosphere will foul the weld zone. Begin welding in the middle of the excavation an inch at a time maximum. Take your time and polish all welds before the next bead as you work from the center weld toward the ends. At a point diametrically opposed to the repair you may need to excavate and clean and reweld to realign the shaft if your initial repair caused too much shrinkage. I know it sounds picky but this repair will not work if the parts are not 100% clean. A MIG repair will not have the penetration as the arc density is not high enough to achieve the strength.

5356 filler is fine. You must use 100% pure Argon purge/shield gas around 30 cfh. You will need around 170 amps AC with moderate high freq and a 2% Thoriated tungsten with the end balled to no more than 1/8 inch diameter. Excavate ahead and beyond the crack completely so the prepped area is smoothly polished so it can be cleaned to perfection. It is almost impossible to overclean Aluminum. CAREFULLY use acetone to clean the weld area and let evaporate COMPLETELY!!!! You can slowly preheat the workpiece before welding with a torch but only a few hundred degrees or the contaminants in the atmosphere will foul the weld zone. Begin welding in the middle of the excavation an inch at a time maximum. Take your time and polish all welds before the next bead as you work from the center weld toward the ends. At a point diametrically opposed to the repair you may need to excavate and clean and reweld to realign the shaft if your initial repair caused too much shrinkage. I know it sounds picky but this repair will not work if the parts are not 100% clean. A MIG repair will not have the penetration as the arc density is not high enough to achieve the strength.


Well, i guess i should have gotten an engineering degree or a welding/metallurgy degree, then i would have known a mig welder/spool gun would not be adequate for welding aluminum driveshafts together. I guess the dozen ive done and the countless ones my older co workers have done in the past couple decades are surely going to fail.

I don't understand the sarcasm. The MIG process is wonderful for many production welds on thinner materials where the two workpieces are within 25% of each other in thickness. Body work and general fabrication work benefit from this process. Many materials can be welded and look cosmetically great with the MIG process but the limited penetration makes it less suitable on material thicker than 3/16". The TIG

Sorry, I did not mean to send the previous post but my pc is touchy. What I started to say about TIG welding is that this process is chosen for critical welding of piping systems and is great for workpieces with dissimilar thickness and heat dissipation properties. It is also the process of choice for welding higher electrical and heat conductive materials such as aluminum and copper nickle alloys. The weld puddle size and shape can be manipulated independently of adding filler and the welder's view of the puddle is unobstructed so gaps and porosity are not covered over by the constant flow of filler material as is the case with MIG. TIG does tend to induce more shrinkage due to the increased pentration of the constant current arc and the ability of the tungsten to carry much higher current and voltage. The .025, .030, or .035 aluminum filler wire simply can not carry the amperage without atomizing and becoming essentially a top coat. Any underliing defects are locked into the weld and reduce strength. I am glad that none of the MIG welded repairs have failed. I would not use the MIG process on critical drivetrain, steering, or suspension components. GM did not use MIG for these welds. We all share the same roads and I just wanted to explain the safest weld repair process.

Sorry, I did not mean to send the previous post but my pc is touchy. What I started to say about TIG welding is that this process is chosen for critical welding of piping systems and is great for workpieces with dissimilar thickness and heat dissipation properties. It is also the process of choice for welding higher electrical and heat conductive materials such as aluminum and copper nickle alloys. The weld puddle size and shape can be manipulated independently of adding filler and the welder's view of the puddle is unobstructed so gaps and porosity are not covered over by the constant flow of filler material as is the case with MIG. TIG does tend to induce more shrinkage due to the increased pentration of the constant current arc and the ability of the tungsten to carry much higher current and voltage. The .025, .030, or .035 aluminum filler wire simply can not carry the amperage without atomizing and becoming essentially a top coat. Any underliing defects are locked into the weld and reduce strength. I am glad that none of the MIG welded repairs have failed. I would not use the MIG process on critical drivetrain, steering, or suspension components. GM did not use MIG for these welds. We all share the same roads and I just wanted to explain the safest weld repair process.

While i cannot argue with your facts, as they are %100 sound, you fail to take into account that the "top coat" is still in fact stronger than the .083 or .121 wall tubing. Its kind of like you and two buddies piss off a bear out in the woods, you don't have to be able to out run the bear, just your slowest buddy. And GM didnt use anything for these welds one of there contractors did, AAM or possibly spicer, and whatever they used im assuming its robotic, and having tooled many factory welds out, i can tell you whatever they are doing does not offer impressive penetration for any of the driveshafts they build, aluminum or steel. Now im just a lowly repair man, but i gotta believe if .030 alum wire can create an arc hot enough to burn a hole through the tubing in question if one is not careful, it will sufficiently penetrate a heavier piece well enough to fasten said tubing to it. Driveline failure is the pissed off bear, and despite the mig welds short comings, the tubing is the unfortunate asthmatic friend with weak ankles and a coincidentally empty inhaler. Leave it to the engineers to over engineer a driveline weld and put chincy wheel bearings and tie rod ends in trucks with a 9200lb gvw.

But at any rate, Dirtymax was happy with his repair, so there probably isnt any need to continue this hi-jack.

Good analogy. I've owned two 3/4 ton Chevy trucks for a span of 23 years and think they are the best but they still have a long way to go. Some of their specs and designs have actually gone backwards. My driveshaft is a one piece aluminum and I always wondered why they would use it versus steel as it amounts to virtually no weight change in a 6700 pound truck (empty). When I plow I am careful because just getting a pile of snow stuck under the truck could damage the driveshaft. What makes it even more prone is the increase in diameter to recover the strength sacrificed by reducing the wall thickness. The end yoke is a substantial piece of material creating an even larger mismatch in weld fit up. Again, poor design. If I ever do damage it I would consider finding a steel version from another 2500HD and replacing the tube to match the length of my aluminum shaft. Good luck with your repairs as you have maximized the MIG process and have a good track record.

My guess for the use of the aluminum shaft is because the increased diameter offers a high critical/safe operating speed for the driveshaft, and the longer the shaft, the lower the critical and safe operating speeds. Now i know that a number of guys have replaced there aluminum with single piece steel and had no problems, but the fact remains that there driveshaft has a lower critical speed than the original. But the catch to that is, a two piece driveshaft with a short front section and long rear section is prone to having balance issues, so the optimal choice was likely an aluminum shaft. But really thats a hip shot as an answer to why they went with an aluminum shaft. Ide like to believe there is an explanation, but then when you look at a 2wd s-10 with a 2 piece driveshaft in which the rear half has 2 double cardan (cv) joints, i have to question whether GM is drug screening there engineers. Also, unless you find a stock steel shaft for next to nothing, 1410 series weld yokes for 4x.083 tube are only like 30 bucks a piece, so you might be money ahead to just have someone bang together a new shaft using your slip yoke rather than retubing a stocker. Which could be done for about $300 bucks using spicer XL series joints and probably $10-$15 cheaper using spicer greasables.