However, if you are experienced and determined to do it yourself, here's a general overview. This is not a complete, step-by-step guide, but a summary of the major steps:
1. Preparation:
* Safety First: Disconnect the battery negative terminal. Use jack stands, not just a jack, to support the truck safely. Wear safety glasses and gloves.
* Gather Tools and Parts: You'll need a variety of specialized tools including axle stands, a gear installation tool, a torque wrench, a bearing press, a differential carrier bearing separator, ring gear installer, and shims. You'll also need the correct replacement rear gear set (ring and pinion) for your specific axle ratio. Consult your owner's manual or a parts catalog to determine the correct ratio.
* Drain Fluids: Drain the differential fluid completely.
2. Removal:
* Remove the Driveshafts: Disconnect the driveshafts from the differential.
* Remove the Axle Flanges: Remove the axle flange bolts and nuts.
* Remove the Differential Cover: Remove the differential cover bolts and carefully remove the cover.
* Remove the Pinion Nut: This requires a very large socket and possibly a breaker bar. Mark the pinion nut's position relative to the pinion gear before loosening it. This is crucial for reinstallation.
* Remove the Ring Gear: This usually requires a ring gear puller.
* Remove the Carrier: This may require separating the carrier bearings.
3. Installation:
* Inspect Components: Carefully inspect all components for wear and tear. Replace any damaged or worn parts.
* Install the New Gear Set: This is the most critical step and requires precision. You'll need to use shims to set the correct backlash and pinion depth. Incorrect setup will lead to premature gear wear and failure. Consult a detailed repair manual for precise instructions on setting backlash and pinion depth. Improperly setting this will ruin your gears.
* Install the Carrier: Carefully install the carrier and bearings.
* Install the Axle Flanges and Driveshafts: Reinstall the axle flanges and driveshafts, ensuring proper alignment.
* Reinstall the Differential Cover: Reinstall the differential cover, using a new gasket.
* Refill with Fluid: Refill the differential with the correct type and amount of gear oil.
4. Verification:
* Check for Leaks: Check for any leaks around the differential cover and axle seals.
* Test Drive: Take the truck for a short test drive to check for noises, vibrations, or other issues.
Important Resources:
* A Detailed Repair Manual: A factory service manual or a reputable aftermarket repair manual specific to your 1994 F-150 is absolutely essential. These manuals will provide detailed instructions, diagrams, and torque specifications.
* YouTube Videos: While videos can be helpful for visualizing certain steps, they should not replace the instructions in a professional repair manual.
Again, this is a complex repair. If you are not comfortable with the level of mechanical expertise required, take your truck to a professional mechanic. The cost of repair will be far less than the cost of replacing a damaged axle or transmission due to a faulty rear gear installation.
