Front Differential Service
Servicing the front differential on a four wheel drive vehicle is an easy job the do it yourself mechanic can perform in the driveway with very little effort and simple hand tools.
Some newer style four wheel drive vehicles have a very simple to service front differential, all that is required is the removal of a drain plug to drain the old oil and the removal of the fill plug to add new fluid. However the ones we will discuss here are the older style slightly harder to service front differentials.
Draining the fluid on an older style front differential requires the removal of the front differential cover.
For this job you will need the following tools:
1. Socket set
2. Short extension
3. Ratchet
4. Single edge razor or gasket scraper
5. large catch pan for old oil
6. Black high temperature RTV
Loosen all the bolts around the perimeter of the differential cover, removing the bolts from the bottom and left and right sides. leave the top bolts in for now to minimize the mess. using a flat bladed screwdriver or gasket scraper pry thecover from the differential body to break the RTV seal.
After allowing the differential to drain remove the top bolts and differential cover. Using the gasket scraper or single edge razor blade remove all the old RTV from the differential housing. Minor nicks or gouges in the gasket surface of the differential body as the new RTV will seal them.
Next you need to remove the old RTV from the differential cover, the easiest way I have found to do this is with an electric wire wheel but lacking this you can use the gasket scraper or razor, it just takes a little longer to clean the cover.
While cleaning the cover check for any areas of severe rust, as these can cause problems in the future if they have not already. If severe rust is present now is the time to replace the differential cover.
Now is also the time to do a quick visual inspection of the gear set up within the differential , just to make sure you can see no obvious damage.
Apply a quarter inch bead of RTV around the differential cover, smooth it all the way around the perimeter with your finger making sure it coats evenly.
Gently place the cover back on the differential body and re insert bolts. Moving around the perimeter tighten all the bolts evenly until they bottom out. This may take as many as three times around the perimeter of the cover.
Now is the time to fill the differential with new fluid. The capacity can usually be found in the owners manual.
