This was my second project with my HH140. After wheeling my S10 ZR2 with 32" mud terrains for a while I noticed that my G80 became very inconsistant with lockup and when it did, it would be very abrupt. After a lot of reading, I found out that the G80 is notorious for blowing up when the clutch packs start to wear out. So I decided to do a little "preventative" maintenance My truck is a DD and trail rig. The whole not spooling or welding anything that gets driven on the street is total bull. Although it will wear the tires a little faster. I've driven spooled and welded cars and trucks on the street with no problems. It just take some adjustments to your driving habbits.
I started by removing the carrier from the housing. Once that was done I removed the ring gear from the carrier so that I wouldn't get spatter or metal shavings on it. With the ring gear off I was now able to cut the 2 pins off on the front side of the carrier that held the centrifigal weights for the locking mechanism. This normally calls for a special tool, but since it was being welded I was not going to reinstall them.
Once the pins were cut out I was able to disassemble the the unit for cleaning. I used brake clean since it doesn't leave a residue( JUST INFORMED THAT THIS IS A BIG NO NO AND CAN BE VERY HARMFUL OR DEADLY. DO NOT USE BRAKE CLEAN FOR WELDING!!!!). With the unit clean I reinstalled the clutch pack so as to have the gears properly lined up with as few gaps as possible. Next came the side gears and spider gears. The cool part about welding a G80 is that it already has a steel center block for the cross pin to go through. The center block and cross pin were installed so that everything was ligned up for welding. I would periodically remove and install the cross pin to make sure that nothing had shifted after welding. With that done I was ready to weld.
I decided to use .030 flux cored wire for a few reasons. The first being that it burns a little hotter and will penetrate better. The second being that I won't have to rent a gas bottle. And third is that I can use a flux nozzle that will allow better access in tight spots( came in really handy). It was a serious pain to clean up. I would stop to clean every few welds because of the mass amounts of spatter. But with the settings on 4/50 and moving slowly, it did the job perfectly and was well worth the extra time.
I started by welding the spider gears to the carrier, side gears, and center block on the front side, periodically switch from side to side and front to back so that I wouldn't overheat the metal. Next was welding the side gears to the center block. I did not weld the side gears to the carrier because the clutch packs created to large of a gap. But that was taken care of later on.
Here is a pic of the spiders welded to the carrier, side gears, and center block. And the side gear to the center block.
Next I welded grade 8 bolts into all 4 corners in between the spider and side gears on the front and back as a filler for added strength. The bolts were also welded to the carrier.
Since I wasn't able to weld the side gears directly to the carrier, I decided to to bridge the gap with 1/4" plate on the front and back. This part was probably overkill, but I would rather waste my time doing it than take the chance of blowing the carrier.
Once the plates were in, I used a grinder to smooth out the welds in order to put the ring gear back on. A pic of the cleaned unit with the ring gear reinstalled at 60 lbs ft is in the next post.
I did run into a problem of the spider gear shifting slightly making it hard to remove and install the cross pin. Not a problem. Grinded the cross pin little by little until it fit nice and snug but still easy to remove. I did not have any problems with axle fitment.
Once that was done I cleaned the housing for installation. Torqued the bearing caps to 70 lbs ft, slid the axles in and dropped the C clips onto the axles through the rear of the center block( has precut openings, do not weld over them). Installed the cross pin and reassemble the rest of the differential.
I have yet to test this offroad yet, but considering I used 4 different ways of welding it, I would imagine that I would be snapping an axle long before even coming close to breaking the welds or carrier. I have however driven it on the street with no problems at all. It does give the typical chirping or chatter around tight turns and makes the steering a little more stiff. Other than that the street manners are unchanged. I found that it is better to let off the throttle while turning so as not to spin out. Getting used to both axles may take a while.
DISCLAIMER!!!!! I AM NOT RESPONSIBLE OR LIABLE FOR ANYONE WHO ATTEMPTS THIS MOD. YOU ARE DOING THIS UNDER YOUR OWN FREE WILL. I AM ONLY PROVIDING THE BEST WAY, TO MY KNOWLEDGE, TO WELD A DIFFERENTIAL CORRECTLY. I WILL NOT REPLACE OR REFUND YOU FOR ANYTHING YOU BREAK OR SCREW UP. I HAVE RESEARCHED THIS FOR A FEW WEEKS IN ORDER TO COME TO MY CONCLUSION OF TE BEST WAY TO WELD A DIFFERENTIAL. THIS IS THE FIRST TIME I'VE DONE THIS MYSELF.
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