Welding rear end of jd 4300

[CliffordK]

I was surprised to hear cast aluminum too, as the differential would seem to be a good place to have a little extra weight, especially the lower half of the differential.

I was initially thinking differentiating between cast steel and cast iron when I asked about grinding.

Different aluminum alloys weld differently. I believe that cast aluminum is considered to make poor welds. However, in this case it certainly is worth a try.

I'm trying to think how you could strengthen the joint, or perhaps improve it. You could tap some bolts into the aluminum, but they would likely work themselves out.

I assume the thicker region in your photo is rearward. You might be able to drill through that area, and bolt on some plates to build up the joint, although it appears to have much less material near the rear.

Otherwise, I might look at cutting off the 3pt on both sides, then building a custom mounting bracket that would go around the rear axles. Or, rather than cutting good parts, at least changing it to utilize any solid mount point that one could for the new bracket, but plan to remount both sides of the hitch.

If this is a common failure point on a relatively new tractor, then used parts will be a pain to get.

 

[arkvet]

I was surprised to hear cast aluminum too, as the differential would seem to be a good place to have a little extra weight, especially the lower half of the differential.

I was initially thinking differentiating between cast steel and cast iron when I asked about grinding.

Different aluminum alloys weld differently. I believe that cast aluminum is considered to make poor welds. However, in this case it certainly is worth a try.

I'm trying to think how you could strengthen the joint, or perhaps improve it. You could tap some bolts into the aluminum, but they would likely work themselves out.

I assume the thicker region in your photo is rearward. You might be able to drill through that area, and bolt on some plates to build up the joint, although it appears to have much less material near the rear.

Otherwise, I might look at cutting off the 3pt on both sides, then building a custom mounting bracket that would go around the rear axles. Or, rather than cutting good parts, at least changing it to utilize any solid mount point that one could for the new bracket, but plan to remount both sides of the hitch.

If this is a common failure point on a relatively new tractor, then used parts will be a pain to get.

I like your suggestions that seem somewhat "outside the box". I'll let you know what I end up with. I am not going to buy a $1,000 rear end though!

 

[Shield Arc]

I have an idea of using some 1-inch thick plate welded to the hitch, and arms that would go back to the bolted plates that sandwich the axle. Not sure if it would be a good idea to cut the other ears off, or us them to help hold the plate with a single padeye and pin through all three.
I tried drawing my idea with Auto-Cad, and even MS paint on this picture, just can't get my idea on paper!

 

[dfkrug]

And I'm guessing an experienced welder can't even fix this aluminum?

I paid an old retired weldor to do the housings on my 1st 4300 project. He was $400 (TIG) and it is still
holding. (A friend now has this CUT.)

On my second 4300, one housing had already been replaced. They ran a bit over $600 several years ago,
and you get the thicker 4310 housing. Getting the housings off is a Big Job. Both threads are posted.

Note that the housings are aluminum, but the center gear case is cast steel. On the current JD 3x20s,
both the axle housings AND the center case is Al.

 

[Kernopelli]

Well, I see Dave already chimed in. I remember his 4300 adventures and was going to recommend searching his posts for the fix.....HE'S the MAN!!

 

[dfkrug]

Well, I see Dave already chimed in. I remember his 4300 adventures and was
going to recommend searching his posts for the fix.....HE'S the MAN!!

And fun adventures they were!

The aluminum debate continues.....

 

[TCJatko]

And fun adventures they were!

The aluminum debate continues.....

Can I assume the housings had to be removed to be welded, or was the guy somehow able to get it done in the field ?

 

[arkvet]

Can I assume the housings had to be removed to be welded, or was the guy somehow able to get it done in the field ?

If it has to be removed to be welded then I'd lean more towards replacing it.. Looks like the labor $ to remove the housing would be very high (or lots of time if DIY)

I've been doing a lot of brainstorming on the back end of this thing and to me it looks like I could build an entirely different hookup by stemming off the huge bolts that already exist on both sides of the rear axle. I could incorporate bolts that actually thread into the housing but am kinda hesitant to utilize the bolts that are set in aluminum... Could turn one problem into many.

Right now I've got the tractor dropped off at a guy that specializes in welding aluminum. I've been told if anyone can fix it... he can. If he can't or if it fails again I'll begin my work on a complete remodel. Since the pto shaft sits well above them (horizontally). I don't see why I couldn't use a large steel bar to span the width and implement it into the long bolts around the narrow part of the axle. Then bridge off an entirely new mount. Might have to cut off the old mount to allow room... or implement it into the fix?

I will post pics when resolved.

Thanks for the advice guys! Love this site!

 

[LD1]

Excellent repairs on that housing. Personally, I wouldnt be afraid to attempt a repair either given the $$$ of replacement. So my vote is welding it.

I too hate cast aluminum in high stress areas. I just had a bad experience with cast AL this past week (well BIL did on his car). T5 manual trans drain plug. NTP threads and thin as heck around the drain itself. Yep...cracked like 1000's of others you can read about...

I was also unaware that the 3x20's were AL. I just though it was the 303x "economy" series. If the 3x20's are AL also, why soo much heavier??

 

[dfkrug]

If it has to be removed to be welded then I'd lean more towards replacing it..

I thought about that too, and looked at how JD tried to address this problem. On
the JD3x20s, the aluminum axle housing has some sort of rod welded on (photo). I
considered beefing up this area, too, but decided that rewelding the whole thing (both
sides) would likely be stronger than a replacement housing.

I don't see how this job could be done well without removing the housings.