Eaton CL-550 Transmission Service Manual

Eaton CL-550 Transmission Service Manual
Eaton CL-550 Transmission

The instructions contained herein cover the disassembly and reassembly of the transmission in a sequence that would normally be followed after the unit has been removed from the machine and is to be completely overhauled.

The CL550 is a 5-speed forward, 1-speed reverse transmission of advanced design offering you the most efficient torque capacity-to-weight ratio of any 5-speed transmission in its torque range. Two basic ratios are available as shown in the table below. The CL551 ratio is designed for use in trucks equipped with a 3 or 4-speed auxiliary transmission and the CL557 ration is designed for use with trucks equipped with a 2-speed rear axle.


Constant mesh in all gears, including low and reverse, is a CL550 feature as is helical gearing throughout, including low and reverse. The Clark split-pin synchronizer is used in 2nd, 3rd 4th and 5th gears. Greater bearing capacity in the CL550 is achieved by the use of numerous needle roller bearings, and two tapered roller bearings and one large straight roller bearing at the rear of the countershaft. Shift forks have replaceable bronze inserts. The shift pattern is of the standard progression type with all shifts having the same throw at the lever. Page B shows a cutaway drawing of the CL550. Page C shows a cutaway drawing of the 390V.

*Mil-L-2105C Extreme Pressure Lubricant (or API classification GL-5) of the SAE viscosity recommended in the chart at the right is preferred. All lubricants should be backed by the reputation of a well-know supplier. It is important to specify EP lubricants of the MIL-L-2105C type only, or of a API classification GL-5.

DRAINING ECONOMY - The object in draining the transmission oil periodically is to eliminate possible bearing surface abrasion and attendant wear. Minute particles of metal, the product of normal wear in service, are deposited in and circulate with the transmission oil. The oil changes chemically, due to its repeated heating and cooling, also the terrific churning it undergoes in the presence of air. It is desirable to drain out this used oil after the first 1,000 miles (1609,0 Km) of service (regardless of type of service). Subsequent drains should be made every 24,000 miles (38616,0 Km) or six (6) months (whichever comes first) for highway service, and every 8,000 to 10,000 miles [12872,0-16090,0 Km] or six (6) months (whichever comes first) “on-off” highway and “pick-up and delivery” types of service. Do this only when the transmission is thoroughly warm.

FLUSHING - After draining, flushing is desirable. Replace the drain plug and fill the transmission to the proper level with a light flushing oil. Drive the transmission for a short period at fast idle in such a manner that the gears in the transmission are rotating without load. This washes out the old oil clinging to the interior of the gear case, covers and shifter rails. BE SURE TO DRAIN OUT ALL of the flushing oil before attempting to refill with new oil. This flushing procedure is most important after first drain.


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