Cracked 38 diff housing

[Timmyb]

Hi guys. Ive been searching for either a 38 or 44 housing to complete my back end. Not having a lot of luck though. I did find a cracked 38,000 housing which I could basically have for nothing. It's cracked where the diff centre bolts in.

Are fabricated housing easier to repair than a cast housing? Or is it still a waste of time trying?

Ive also read that it's usually the back diff which cracks. So if it was repaired and ran in the front would this help any? Included is a pic of the crack. It's about 3 inches long. 

[Vladislav]

A fabricated housing should be weldable. I would do it as usual. Drill holes in the ends, cut out along the crack and weld. Better try to do it both sides.

Unfortunately I have almost nothing experience on how long it would last. Hope other folks will point you out on that.

Four years back a rear housing on International Harvester 9400 had a crack along the cenrtal hemisphere where it was welded into the banjo. A guy cut the crack on the outer side only since the axle was on the truck and filled with oil. He welded it and no troubles so far. I don't know the real milage the truck has done to the moment, nearly one tyre set is gone from that day. With the road conditions couldn't be described as smooth and easy.

I have an extra 44 cast housing laying in the yard. Come and get it! 

[fjh]

I've welded plenty of those go for it grind it out and pour some rod into it.

Edited November 5, 2016 by fjh

[Timmyb]

Thanks for your opinions guys. I guess it's worth a try as at the moment I don't have an alternative. Arc or mig a better way? I think with a short rod on the arc I could probably get both sides welded. 

Vlad, how about I meet you half way? 😜

[41chevy]

13 minutes ago, Timmyb said:

Thanks for your opinions guys. I guess it's worth a try as at the moment I don't have an alternative. Arc or mig a better way? I think with a short rod on the arc I could probably get both sides welded. 

Vlad, how about I meet you half way? 😜

I personally think a short stick is better. Drill stop holes at each end of the crack, Vee it out, weld it up. Peen  the weld with a hammer to stress relieve it and  run it.    Paul

[Timmyb]

3 hours ago, 41chevy said:

I personally think a short stick is better. Drill stop holes at each end of the crack, Vee it out, weld it up. Peen  the weld with a hammer to stress relieve it and  run it.    Paul

Thank you Paul. I appreciate the advice. 

[terry]

11 hours ago, 41chevy said:

I personally think a short stick is better. Drill stop holes at each end of the crack, Vee it out, weld it up. Peen  the weld with a hammer to stress relieve it and  run it.    Paul

Not trying to hyjack this thread, but what does peening the weld actually do?  Do have to do it after each pass of welding ?  terry

Edited November 6, 2016 by terry

[james j neiweem]

I believe peening makes the weld area less brittle. Also make sure you use the proper weld wire or rod. Good luck.

[eddeere]

I have been told by a numbers of good welders peening relives the stress.

[theakerstwo]

7018 rod

[41chevy]

4 hours ago, terry said:

Not trying to hyjack this thread, but what does peening the weld actually do?  Do have to do it after each pass of welding ?  terry

I do it each pass.  Peening relieves the stress like was said above.

When I got my U.S.Navy weld certification at Grumman Aircraft in 1972 we were showed the difference a peened weld on the F-14 Tail hook and a welded non peened tail hook weld worked.  The non peened weld fractured between the bead and the parent steel. Some use a ball peen hammer and some use a air scaling hammer. Either on works well.

Like Glenn said 7018 rod or 7018E low Hydrogen rod are the best ones to use, you'll get a strong good penetrating weld . A bit harder to strike an arc then drag rod, but the end results are worth it. 

  Do the weld in 1 inch or so passes from the ends and than fill the center bead in, that will stop the crack from heat induced traveling, peen it, grind it and run it.     Paul

Edited November 6, 2016 by 41chevy

[terry]

Thanks for that info, very interesting !     terry

[BillyT]

I agree with 41 on the peening, also the stop hole!( prevents the crack from continuing) grind the crack slightly wider than the electrode ( the wire,not the coating) and make it as smooth as possible.Lightly preheat the area to remove moisture,strike the arc ahead of the crack and and weld into the crack.I would weld half of the crack and let it cool til you can almost touch it.Peen the weld and slightly beyond it,I use a round tipped chipping hammer.Strike your next arc on the end of the last bead and weld to the hole. It looks like no more than two passes should do it.Definitely use 7018 low hydrogen dc electrode positive.I cannot emphasize enough the electrode should be dry! If the electrode is old or questionable buy a pound of new wire! I've never seen a diff. Crack at that location,could be a flawed casting.If so the weld will almost surely hold (no stress)! Good luck !😁 low hydrogen is more susceptible to moisture than most other popular electrodes!

[41chevy]

And the Low Hydrogen 7018E rod prevents embrittlement of the weld area.    Paul