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R/R welded diff?


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Once you weld your diff......and break a stub....

 

How do you remove your diff gears or do you just replace the whole thing....?

 

Just thinkin ahead to Moab.....:rolleyes:

 

Thanks,

Glenn

82 Summer, welded diff....

01 Forester, LSD......

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Originally posted by ShawnW

Does that mean there might be something useful to be taken out of the spare 3.7 and 3.9 rear diffs I have in my basement that are destined for the crusher?

 

Yes it does. We had 6 extras at the Rubicon and used all but one. Funny thing is, before that I'd only seen one break ever.

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I'm stupid,:eek: or just havn't spent any quality time with my diff thingy.

 

Having stated the obvious, The stub that sticks out can be unbolted and replaced leaving all the welded gears inside happy:) and inplace?

 

Glenn,

82 Summer, contemplating slickrock......:rolleyes:

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how do you weld them in the first place, just crack it open and weld the spiders, then put it back together. is there anything important to keep in mind while doing this, like pinion preload, or backlash?

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Thanks Zap! I think I'll get one.

 

Ok - as for welding the diff, I just did that, and my research sugested that welding the side gears together is the best approach. Some people have welded the side gears to the carrier, but this is less strong as the gears are tool-steel, and the carrier is cast I think. At any rate, it's best to weld similar metals for strength, and gear to gear will get you that. Basically, we (Bugaru and I) just decided to weld the thing at each place where the gears come together - so four welds on each side. We removed the diff from my car (20 minutes if that), and drained the gear oil. Inspected the diff to make sure we were welding something that was in good shape in the first place, and then gave it a good cleaning with brake cleaner. Brake cleaner leaves no residue, so that was our reasoning for using it - we wanted the metal as clean as possible. I didn't have my compressor up and running, but I would sugest using compressed air to get it all dry and ready for welding. We just let is sit overnight to make sure it was throughly dry. The welding process itself was pretty quick, and we found that we got great penetration on the welds, so I have no fear of my diff ever breaking. We used a Lincoln 220 volt Mig setup, with 100% CO2. I think the 100% CO2 mixture gave us more penetration, but a little bit more splatter to clean up. We conjectured that a mixture with more argon would result in less splatter, but after seeing the results, I think I would rather go with the 100% CO2, as the welds seem insanely strong. After that, I filled the diff with motor oil, and worked it around till I got all the splatter ground up, and drained out. Filled it with gear oil, and installed it in the car. I've taken it out on some rough stuff twice now, and it's been awesome so far.

 

I'm not a welder, so if anything I said was incorrect, please feel free to correct me. Bugaru did the actual welding - I just helped with the prep work, and such. Just reporting what I have experienced....

 

GD

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cool, i think i may do that to the suby 3 offroad version 2. thanks.

and i guess the draw back would be having a better chance of broken stub shafts and cv axles. of course the sqeaky tires on the dry stuff.

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If you don't remove a rear axle for pavement travel, a sharp turn can litterally blow the axle apart. At the very least, it will almost certainly break. The axles are not very strong. The stub axles can break too, and with the higher crawl ratios of the t-case modded folk out there, these seem to be a weak point. I think Jared said he has broken 4 now. It's not *as much* of a problem for us without the t-case, but they can still break. I saw one that Qman broke - twisted it right in half.

 

GD

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Hey Q man, how did U get the little busted pice of the stub out of the dif. after a snaped stub? I have one that Adam is working on that is stuck in BAD!

If it helps I welded the non ring gear side, side gear to the carier, and pin gears to that side gear. When I snaped the stub it also busted my welds:o

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