REPAIR INSTRUCTIONS Replace shift rails if they are cracked in either the poppet or setscrew holes. If the clearance between the shift rail and housing (cover) bore exceeds 0.254 mm (0.010 inch) maximum, determine which part is worn before replacing. Shaft wear can be checked by measuring the shaft at an unworn location. Then measure the shaft at the worn area and compare measurements. When measuring a shift rail, the reading should be an average of diameter measurements taken at four locations. Compare one side of the shaft to the other, AB–CD as shown in Figure 302.
Be careful when installing a shaft through a new seal (or seal over shaft). Lubricate the shaft before inserting it through the seal. Splines, keyways and holes in a shaft can damage seals unless care is taken. Lubricate the seal to prevent damage during the initial start-up period, before normal lubrication begins. Keep anti-seize and sealing compounds away from oil seals.
302
Lip-type oil seals are precision elements that require close attention and care during installation.
If an oil seal does not have a preapplied sealant on its outer diameter, apply an appropriate sealer around the outside diameter to prevent leaks.
The quality of the installation method and tools used has a direct influence on the life of the seal. Do not use a block of wood or discarded bearing as a substitute for the proper seal driver. However, with some seal applications, a seal driver may not be available. In these situations, light tapping in a circular motion using a light, broad-faced hammer is acceptable. Figure 302 — Measuring Shift Rail
Oil Seals [321] When an overhaul is required, replace all oil seals. Be careful to ensure that the sealing surface of any seal is not damaged, turned back or cut. A nick on a shaft sealing surface can cut the seal. Remove sharp edges that can damage the seal (chamfer edges if possible). Press seals into housings, using smooth, even pressure to prevent cocking the seal.
For the seal to function properly, install it squarely with respect to the shaft center line. The seal should be kept square within 0.254 mm (0.010 inch) Total Indicated Runout (TIR). Squareness of the seal to the shaft is controlled by using the proper seal installation tools, as shown in Figure 303 and Figure 304.
Be careful when using any abrasive polishing methods, such as emery or crocus cloth, on a sealing surface. It is possible to leave microgrooves on the sealing surface. This can cause oil to leak past the sealing lip(s) of the oil seal. With this condition, a new seal will not stop the oil leak.
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