In-situ maintenance of the loader transmission

A ZL50C type loader experienced severe weakness in reverse gear during construction. It was determined that the oil seal of the reverse gear piston was damaged. The usual repair method is to remove the cab, engine, torque converter and transmission together. In this way, it is both laborious and labor-intensive, and it also affects the construction progress.

Based on our experience, in-situ maintenance can be carried out by:

First, drain all the hydraulic oil from the transmission. Then, remove the 10 (M10×30) fixing bolts on the transmission end cover and take off the end cover. Screw two M10 bolts into the lifting screw holes of the middle output gear and remove the direct stop assembly. Unscrew the 8 (M10×40) fixing bolts on the middle cover plate, and remove the I-stop cylinder assembly and the I-stop piston assembly. Remove 15 springs and spring pins; Remove the driving and driven friction plates of the I gear clutch (1 each), then take out the internal gear ring of the I gear and the remaining driven and driving plates (3 each). Remove the I-gear planetary gear carrier and the reverse gear internal gear ring assembly.

Remove the friction plate isolation frame assembly; Remove the driving and driven friction plates of the reverse clutch (3 pieces each). Screw two M10 lifting screws into the lifting screw holes of the reverse planetary gear carrier assembly to remove the reverse planetary gear carrier assembly, and then remove the remaining driving and driven friction plates (one each). Remove the reverse piston assembly.

After the oil seal is replaced, reassemble it in the reverse order of disassembly.

This in-situ maintenance method is very time-saving. The entire repair process only takes 2 hours and is safe and reliable. There is no need to use a crane, and the repair task can be completed by one person.

After assembly is completed, the "oil and gas" test is conducted. The method is: First, remove the variable speed distribution valve; Oil is injected into the piston cylinders of each gear through the oil passage on the housing until they are full. Align the air pipe with each oil passage opening and introduce compressed air at 0.6 to 0.8MPa. If you can hear a "pop" sound when the piston strikes the driven plate at the moment of ventilation, it is in good condition; otherwise, it should be reassembled.

During the repair process, it should also be noted that bolts, washers, tools and other parts must not fall into the bottom of the shell. After installation, the filter element should be removed to check if any bolts, tools, etc. have fallen into the bottom of the shell. When tightening the middle cover bolts, they must be tightened symmetrically. When disassembling, the spring must not be popped out. Remember the installation sequence and quantity of the friction plates. Do not install them in reverse or omit them. When installing each piston, the oil seal must not be damaged. When disassembling the variable speed distribution valve, the gasket must not be damaged. If the gasket needs to be reinstalled due to damage, it is necessary to ensure that the oil passage is unobstructed and does not leak, etc.