I strongly recommend seeking professional help from a qualified mechanic or transmission shop. They have the proper tools, experience, and knowledge to perform this repair correctly and safely.
However, if you're determined to attempt this yourself, here's a *general* outline of the steps involved. Remember, this is a simplified overview and details will vary based on your specific axle type:
1. Preparation:
* Safety First: Disconnect the battery's negative terminal. Use jack stands to securely support the truck after lifting it. Wear safety glasses and gloves.
* Gather Tools and Parts: You'll need a variety of specialized tools including a bearing puller, a pinion nut socket (often a large, deep-well socket), a torque wrench capable of high torque settings, a dial indicator, a shim kit, a new pinion bearing and seal, possibly a new pinion seal retainer, and other common automotive tools.
* Consult a Repair Manual: Obtain a factory service manual or a reputable aftermarket repair manual specific to your 1999 Dodge Ram 1500 4x4. This manual will provide detailed instructions, torque specifications, and diagrams crucial for successful completion.
2. Axle Removal (or Partial Disassembly):
* Remove the driveshaft: Disconnect the driveshaft at the differential and the axle.
* Remove the axle: This might involve removing the brakes, axle shafts, and possibly the entire axle housing depending on the design. Consult your repair manual. You may be able to leave the axle housing in place, but many will require removal.
3. Pinion Bearing Removal and Installation:
* Remove the pinion nut: This requires a significant amount of torque. Use a breaker bar and appropriate socket. Mark the nut and shaft for reinstallation in the exact same position.
* Remove the pinion seal: Carefully remove the pinion seal using a seal puller.
* Remove the pinion bearing: Use a bearing puller to remove the pinion bearing from the pinion shaft.
* Install the new pinion bearing: Carefully install the new bearing onto the pinion shaft using appropriate tools and techniques to avoid damage.
* Install the new pinion seal: Install the new pinion seal, ensuring it's properly seated.
4. Reassembly:
* Install the pinion nut: Tighten the pinion nut to the torque specified in your repair manual.
* Set pinion depth: Use a dial indicator to accurately measure and adjust pinion depth (shimming) according to your repair manual's specifications. This is crucial for proper gear mesh and bearing life. Incorrectly setting the pinion depth can ruin your gears.
* Reassemble the axle: Reassemble all components in the reverse order of removal, following your repair manual's instructions meticulously.
* Torque specifications: Ensure all bolts and nuts are tightened to the manufacturer's recommended torque specifications.
5. Testing:
* Fluid refill: Fill the differential with the correct type and amount of gear oil.
* Road test: After the repair, perform a thorough road test, paying close attention to any unusual noises or vibrations.
Again, I strongly advise against attempting this repair unless you have extensive mechanical experience and access to the necessary specialized tools and a repair manual. The risk of causing further damage and incurring significant repair costs far outweighs the potential savings of DIY. It's far better to invest in professional help and ensure the job is done correctly.
