ERROR FOUND IN FORD PARTS BOOK!!!
Ford parts book PA-8800-C on page 4-20, item
number# 8, lists part # D1NN-4N028-A for both
ends of the pinion shaft on the model (ALL
PURPOSE) 21201 and 600 LCG.
THIS IS INCORRECT!
Although the rear end will assemble with these
parts, the mesh of the ring and pinion will be
incorrect, resulting in short gear life.
The number indicated is correct for bearing for the
front end of the pinion, but the back end (gear-end)
is not correct.
The correct number for the back bearing is:NCA
4630-A. This is equivalent to Timken HM 804843.
The parts book listed the correct cup for the
bearing.(TBAA-4628-A) = (TIMKEN # HM 80410)
This error was discovered when I attemted to determine the cause of repeat ring-gear failures with all new parts. After weeks of trial and error, shimming and spacing the pinion, I finally obtained an acceptable contact pattern for the ring and pinion. I did not like having to shim an assembly tha the factory indicated should fit without shims, but at the time I had no choice.All indications from Ford indicated the proper parts were installed.
I cannot leave a bone buried, however, and I would often awake at 4 am wondering what was really wrong with the picture: Something about it didn't digest well. I finally decided to research the cup number on the TIMKEN BEARING website.
I searched by the shaft diameter (1.750) and the Cup Diameter. (3.750) WALLA! There it was :!!
The proper cone(HM804843) for the cup(HM804810).
The rear end has now being disassembled and the shims and spacers have been removed.The proper bearing was installed and everything fits properly with no shims.The only adjustment needed is preload on the ring carrier bearings, which BERN covers on this forum very throughly.
BERN has been a tremendous help to me
throughout this whole project, going the extra mile to assist. I wholeheartedly recommend his advice, and thank him for his support.