Here's a general outline, but I strongly advise against attempting this yourself unless you have significant experience with automotive repair, specifically transfer case work:
1. Vehicle Preparation: Disconnect the battery, safely support the vehicle, and drain the transfer case fluid.
2. Transfer Case Removal: This usually involves removing the driveshafts, disconnecting linkage, and unbolting the transfer case from the transmission. The exact process varies depending on the specific transfer case (NP246, NP261, etc.) installed in your Silverado. Consult a repair manual specific to your truck's model and transfer case.
3. Transfer Case Disassembly: Once the transfer case is removed, you'll need to disassemble it. This typically involves removing the chain case, separating the front and rear output sections, and then carefully removing the various components, including the planetary gear set (which contains the spider gears). You'll need various sockets, wrenches, and potentially specialized transfer case tools (like a chain case separator).
4. Spider Gear Removal: The spider gears are usually held in place by pressure and sometimes retaining clips or pins. Precise removal is crucial to avoid damage. You'll need to carefully separate these components.
5. Reassembly: Reassembly is the reverse of disassembly. Pay close attention to the correct orientation and positioning of all parts. Use new gaskets and seals to prevent leaks.
Crucial Considerations:
* Repair Manual: A factory service manual or a reputable aftermarket repair manual for your specific 1999 Chevrolet Silverado is absolutely essential. It will provide detailed instructions, torque specifications, and diagrams.
* Specialized Tools: You'll likely need specialized tools for transfer case disassembly and reassembly, including possibly a transfer case holding fixture.
* Experience: This is not a job for a novice mechanic. Improper disassembly can cause serious damage to the transfer case, rendering it unusable.
* Safety: Always prioritize safety. Use jack stands, work in a well-ventilated area, and wear appropriate safety gear.
Recommendation: If you're not comfortable performing this repair yourself, take your Silverado to a qualified mechanic specializing in transmissions and transfer cases. The cost of repair will likely be less than the cost of damaging the transfer case during an attempted DIY repair.
