Many – too numerous to list, covering a vast range of designs, sizes, and materials suitable for a never-ending range of applications. Some designs conform to International Standards such as BS1399 and DIN 3760 for metric sizes and seal types, but the majority have been manufactured to suit particular applications – hence the enormous selection available. This blog is intended to assist in this selection and will consider seal type, materials, and sizes.
If this is not possible, you may be able to fit the lower retaining bolt into the upper mounting support, to hold the engine level. Or the gearbox may have to be jacked up and supported.
Shaft Hardness

Prepare the shaft and prevent damage
Figure 5 explains the JTEKT seal numbering system.
Seal numbers consist of
(1) the seal type code,
(2) the spring code,
(3) the lip type code,
(4) the dimensional numbers, and
(5) the special type code,
and Table 6 shows examples of each of these codes/numbers.