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.
Oil seals normally consist of three basic components: the sealing element, the metal case, and garter spring.
There are a few options to remedy this situation:

metal cased oil seals. They can be used with a wide range of oils, greases, and other lubricants, making them suitable for various industrial applications. Additionally, these seals can withstand exposure to harsh chemicals, extreme temperatures, and abrasive materials without compromising their sealing capabilities.
Table 3: Requirements
In general, oil seals should be selected in the order of priority indicated in Table 1.
Metal O.D. wall
(with a reinforcing inner metal case)
Choosing the right oil seal
ERIKS also supplies the types GR and GRST. These are virtually identical to the types R and RST, except in this case the metal inner ring is also completely encased in rubber. ERIKS uses FKM rubber here as standard, so these seals are ideal for use in acidic environments.
When deciding on the best type of seal for a particular application, it is best to consider all aspects of the environment and its purpose. If the application requires a spring- loaded seal, that does not eliminate either the rotary shaft seal or the mechanical seal. If the equipment is operating in extreme temperatures, including situations where the rapid movement of the equipment creates extreme heat, a mechanical seal will hold up better than an oil seal.

Common lip materials available for use in our oil seals include:
Different Type Rotary Shaft Oil Seal
Most ERIKS oil seals, such as the types M, MST, R and RST, are made of NBR as standard.
Car Iridium Spark Plug: Advantages and Performance
Leather oil seals have great running properties and are mostly used for abrasive applications.