Coventry West is one of the largest rebuilders of Jaguar differentials in North America. We like to point out that these units are not particularly easy to rebuild without special fixtures, such as a case spreader. And while we can supply all the bearings, seals, and spacers necessary to rebuild Jaguar diffs, in general we do not recommend field-rebuilding these units due to the special tools needed. Below is an overview of the process your differential goes through.
1. The differential core is stripped and checked for any obvious damage to the gears, spiders, shafts, case, etc. The case is then hand and steam cleaned. If rust is present, it is either wire-brushed or glass-bead blasted. If the case is glass-beaded, it is steamed cleaned again. Then the case is painted black.
2. The gears are checked for rust, pits, scoring, bluing (a sign of overheating from lack of oil), and any other damage. The gears are the strongest part of the differential and if they are bad, the diff is destroyed and is not rebuildable. On posi-traction differentials, the clutches are removed and examined. Any damaged or broken clutches are replaced along with any other damaged parts.
3. The stub axle procedure varies depending on the type of differential. Overall, the axles are taken apart, cleaned, and glass-bead blasted. The bolts are replaced if bent. The threads are chased and the axle is painted. The axle has its sealing surface polished to a mirror finish. The seal is installed with silicone sealer. Then the axle is assembled.
4. The front flange is cleaned, bead-blasted, polished, and painted. If the flange is bent or damaged, it is scrapped.
5. The differential receives all new bearings and seals. It is assembled to specs and the gear mesh is checked for proper gear contact pattern. If it is not correct, the diff is taken back apart and readjusted, as an incorrect gear contact pattern will cause noise on an otherwise nice diff.
6. The rear cover is cleaned and burnished, and the breather tube is resealed. The rear cover is then installed on the diff with either a gasket and sealer, or just sealer depending on the year of the unit.
7. A magnetic drain plug is installed on all Coventry West differentials. The stub axles are installed and the bolts either wire-laced or Loctited, depending again on the year of the diff. The completed unit is then carefully boxed in a double cardboard box with a custom foam surround to insure that it is not damaged during shipping. All Coventry West differentials carry a 12-month unlimited mileage warranty!