Tonight I split the transfer cases apart with the goal of swapping the 23 spline input gear from the Dodge case to the Jeep case because it came with a 21 spline gear and I need 23 spline for the 46RH transplant. Here's a little writeup on what I did. If anyone sees any omissions or has any questions, please let me know.
There are a few differences between the Dodge and Jeep cases, but they are mostly the same. I took pics as I disassembled the Dodge case because I did that one first.
Drain the case first. You'll still end up with fluid on your bench, hands, lap, tools, whatever. Make sure you loosen the fill plug before the drain so you know you can get fluid back in it. As I disassemble each piece, I clean it with some brake cleaner.
First, I removed the front yoke. I used my impact. If you don't have an impact, take the front yoke off before removing the t-case from the vehicle so the wheels/engine keep the yoke from spinning. I put some vise grips on the flange to help keep it from spinning.
After that, I took the 4 10mm bolts off the bearing retainer.
The bearing retainer is sealed with RTV, so it needs to broken off gently. Remember, the case is aluminum. There's a little notch on each side, 180º from each other. I just pried gently with a screwdriver and it popped off.
This is the input shaft that needs to be removed.
The case needs to be split to remove this. There are 15mm bolts around the outside of the case that all need to come out. On the Jeep case, there was one 12-point 10mm bolt on the top in the middle. I have no idea why.
A few of the bolts are different from the others. The little smudge of yellow paint is what I used to mark where the different bolts went. After the bolts are out, split the case halves. Again, it's sealed with RTV. There are two openings you can carefully pry with a screwdriver.
Once you break the seal, you can wiggle and slide the two halves apart. Be careful not to drop anything.
Remove the mode fork and rail, mode sleeve, range fork and range hub. Don't loose the spring. Make note of how it all goes together. The mode sleeve has two different sides. It should all just slide out from it's home. The range hub and the mode sleeve that live in their respective forks pop out pretty easy, so be careful.
The input shaft is in the planetary gearset. To free the planetary gearset, you have to remove this lockring on the outside of the case. This is under the bearing retainer removed in a prior step. Now, a good set of lock ring (NOT snap ring) pliers does come in handy here, and some would say absolutely necessary, but I did it without them. That being said, I did order a new pair to speed up this job because there are 3 lock rings I needed to remove and reinstall. Because they are reused, you can't mangle them.
They can be a pain to remove. There it is.
After that, the planetary assembly is removed from the inside of the case half. I tapped it a little with my deadblow hammer to loosen it and it came right out.
Now that the planetary is removed from the case, there's another lockring to remove. This one holds the input shaft in the planetary assembly.
Under the lockring, there is a retainer and a tabbed washer. The tabbed washer has little detents in it. Make note of the order they come out.
After that the input gear is freed!
At this point, all that needs to happen is install the new input gear and assemble the case in reverse order of removal. Clean of all the old RTV, being careful not to gouge the mating surfaces. I used a wire cup on my die grinder after I picked off the big stuff. There are a few special notes below about the input bearing
and oil passage
near the end of this write up. If I was using a Jeep 23 spline input gear, I probably wouldn't have an issue with the bearing.
Here are the differences between the two gears. Dodge on left, Jeep on right.
Again, Dodge on left, Jeep on right
I measured the retainer and tabbed washer to make sure there was no difference in the thickness because it would have affected where the gear ended up. They were identical.
I reassembled the input gear into the planetary assembly, then installed the planetary assembly into the case half. I turned the shaft by hand and felt a little binding every half turn. If I spun it fast, it sort of went tick-tick-tick as it spun. If I spun it slow, it had a little resistance when it hit that point. It was so slight I almost left it, but it was bothering me so I pulled it apart and inserted the assembly into the Dodge case half and the noise was gone. I looked at the bearing that the input shaft sits in, and the Dodge case was flush on the inside, while the Jeep bearing was recessed. The case thickness is the same; the Jeep bearing is smaller. Because the bearing was smaller, the input gear was set in the case too far and was hitting a rib on the case.
So I set out to swap the bearing too. Again, I don't think this would have been an issue with a Jeep input gear.
There's another lockring on the outside that holds this in. Needs to be removed.
I grabbed my race driver and popped out the bearing.
Did the same on the Dodge case and installed the Dodge bearing into the Jeep case. Noise was gone.
While I had everything apart, I noted that that the Dodge chain is 1/4" wider than the Jeep. 1 1/4 inch vs. 1 inch.
I did a little research an seen others have done different Jeep/Dodge/Chevy t-case mash ups before, although I didn't see anything exactly like this. So I set off to see what it would take to get the Dodge chain in the Jeep case. I thought it would be a nice little upgrade.
The mode ring and gear are bigger as well.
So there's another lockring to undo which allows the mode hub and drive sprocket to slide off the mainshaft. Then I simply slid the larger Dodge sprockets, chain and front output in place of the Jeep stuff I just pulled out. This part is just like a regular SYE install, except the sprockets get replaced instead of the mainshaft, but the steps are the same so I didn't take any pictures.
There's one thing to point out when reassembling. There is an oil passage that must be aligned when the bearing retainer is reinstalled. You can see the passage in the cover and the extra hole in the case. It is at the bottom of the bolt pattern. Don't forget RTV on the cover.