The problem is that the failure *implies* other internal damage. Metal fragments from the cracked case could be inside, potentially damaging gears or bearings. Even if visually inspecting the internals looks okay, microscopic damage could lead to premature failure.
Therefore, while you *can* replace the transfer case without touching the internals *initially*, it's a risky approach. You'd be better served by:
1. Professional Inspection: Take the transfer case to a transmission shop or qualified mechanic for a thorough inspection. They can assess the extent of the damage, both visible and hidden.
2. Repair or Replacement: Based on their inspection, they'll recommend repair (if feasible and cost-effective) or a replacement transfer case. Repair might involve welding the crack (though this is not always advisable on a cast-aluminum case), but it requires significant expertise. Replacing the entire unit is usually more reliable and often less expensive in the long run.
3. Addressing the Root Cause: The bad U-joints caused the failure. This needs fixing *before* installing the new or repaired transfer case. Replacing only the U-joints is insufficient; thoroughly inspect the driveshafts for damage as well. Bent or damaged driveshafts will quickly wreck another transfer case.
In short: While physically removing and replacing the transfer case is possible without disassembling it *initially*, doing so without a proper inspection is foolish and could cost you more in the long run due to internal damage. Get it professionally evaluated first.
