Hi guys, I'm new to gear swapping and had a question that I haven really found the answer to after searching. So, I have a tapered D44 with 5.38 gears under my Jeep now and I just picked up a 1971 flanged D44 with 3.73 gears. I was wondering if it was possible to swap gear sets between the housings. I want to put the flanged rear under my Jeep with the 5.38s and I have a friend who said he would buy the tapered one if I could put the 3.73s in it, so win/win, but aside from having someone proprely set up the gears, what else would I need to do? Thank you!

Won't the splines on the side gears be the show stopper? I should add that there will be more involved than just a straight swap since the axle splines are different.

Your tapered axle has a series IV differential case with either 10 or more likely 19 splines. Your flanged offset axle has a series III differential either Trac Loc or open with 30 splines. So you need to get that sorted out. 5.38 must use a series IV differential 3.73 must use a series III differential Side gears (spline count) can possibly be swapped as required. But you cannot swap Trac Lok side gears with open differential side gears. I can sell you an open differential for cheap if you are interested. I can also supply you with " case set up bearings".

Thank you for your detailed reply. They are both open diffs. So if I understand correctly, I can't just swap the differential, gears and all from housing to housing? If that is possible, would I then just have to get new side gears to match the axle splines?

Maybe I can help ... there is a "case break" separating 3.73 and down numerically vs. 3.92 and up numerically for the 44. This is the series III and series IV that oldtime describes. So you need to use the case that is compatible with the gear ratio. You also have to match the spline count of the side gears to the axle shafts. So at a minimum, you would have to exchange the side gears from one case to the other for the "differential, gears and all" to go into the new housing. In addition to the usual setup...

Because they are both open it will be a much easier thing to comprehend. You can leave the ring gears on their respective differential cases. If you set the cases on end next to one another you will clearly be able to see the different case offsets. You must pull the side gears (AKA spiders) out and swap them from one case to the other. Side gear end play upon refitting must be within specification. Then simply refit differential case with its original ring gear into the other axle carrier housing. Note: the simple refit of case is actually a very complicated procedure.

You will also have to swap the Pinion gear and reset it up as well on both as the Ring and Pinion go together as a set.

Thank you for all the replies. I think I have a good grasp on what needs to be done now. I also just picked up a series IV Powr Loc, so I'm going to throw that into the mix while I'm at it.

Great find ! I wish I could find another one. Have not seen any of those available.... going on 3 years now.