2 Big Broncos Rocky Mountain Site
Differential Work
Parts used:
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US Gear 4.56:1 gears in both ends
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Complete overhaul kit for front Dana 44
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New carrier for front Dana 44
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Lock Right locker for front Dana 44
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Parts from Randy’s Ring and Pinion
Again, with my attempt to do as much of this work as I could myself, I decided to tackle the differentials. Many thanks go out to Jeremy Little and the others at Randy's Ring and Pinion for providing so much help. They never suggested that I just send the diffs to them and let them do it. Even when I called to order tools, Jeremy told me what to do to avoid the expense.
I chose the rear 9-inch differential to start with. Since I had already had the diff rebuilt and a Detroit installed, I knew that it would be a lot less work to complete. After removing the diff from the rear housing, I completely disassembled the case. I pressed on the new pinion bearings with a new seal and set the pinion preload. This was pretty tough to do. I eventually ended up with two 6-foot breaker bars to collapse the sleeve and get the preload right. Once the pinion was in, I installed the Detroit with the new ring gear installed and tried to set the backlash. As the backlash got close to being right, the sharp click of the gears hitting each other turned into a thud. It turns out that the 4.56 ring gear hits the pilot bearing support in the case. I stripped the entire case apart again and ground the support slightly to clear the gear. After a thorough cleaning, I reinstalled the gears and proceeded with the setup. Pinion depth only required three tear downs to get right. Once the backlash was set, I cranked the adjusters tight and gave everything a final torquing. The final step was to recheck backlash and check the gear pattern around the entire ring gear. It all looked good, so back in the truck it went.
So far, the front Dana 44 has me pretty worried. It requires that the bearings be removed to change all of the adjusting shims. I get nervous pulling bearings over and over, it's an invitaion to disaster. I'll finish that write-up when I get it done.
Turns out the D44 was very time consuming, but not as difficult as I had feared. Here's a few pics to hold you over until I can get the story finished.
My
bearing removal setup. I used a bearing separator from Harbor Freight tools
along with a two-jaw puller. I used an old socket and a chunk of iron as a
load-bearing surface. The puller was digging into the iron pretty bad, so I
picked up a brass 3/8 pipe plug, drilled a dimple in the end of it, and used it
as a bearing between the puller and the iron. This setup was the nut for doing
this work.
The tricky part of pulling these bearings was not tearing up the shims under the bushings. With a little practice it got pretty easy. I used my hydraulic press to reinstall the bearings. In total, I had to remove and replace the bearings about eight times. The old bearings were used for all checks. The new bearings were installed after all clearances and preloads were checked. A final check of all measurements verified that nothing changed with the new bearings.
The
new pinion installed in the case.
The
completed differential.
A
close up of the pattern. I believe this pattern is still a bit high (towards the
face of the teeth), but it does not touch the edge of the tooth. Since this is
the front differential, and I would have to destroy a large oil blocker under
the inner bearing race to change to change the pinion depth, I decided to leave
it alone.
The completed carrier assembly.
There
can be a LOT of shims under the carrier bearings. The shims come in .0025",
.004", .009", .014" and .023" sizes. You have to mix and
match to get the right thickness.
This is a pretty poor picture, but it shows the Lock Right installed in the
carrier.