153
1-housing; 2-coupling; 3-shaft; 4-shaft bushing; 5-engaging chamber body; 6-engaging rod; 7-fork; 8-
spring; 9-cover; 10-diaphragm; 11-gasket; 12-flange; 13-collar; 14-cover; 15,23-ball bearings; 16-pump
connecting rod; 17-piston; 18, 21-pump valves; 19-plug; 20-safety valve; 22-pump body
Figure 129 - Auxiliary Power Take-Off
The pump consists of piston 17 with delivery valve 18, safety valve 20 and body 22. The
piston with the connecting rod is mounted on the eccentric of shaft 3; the piston performs transla-
tional motion as the shaft rotates. To prevent an excessive pressure rise with increasing rotational
speed, the suction valve is of differential type and has a cylindrical spring. The oil is taken from
the transfer case oil sump through a pipe and then the pump forces oil to the gear bearings via
channels in shaft 3 and in primary shaft of the transfer case. Some oil penetrates through the gaps
and lubricates the shaft bearings.
Information about auxiliary power take-off control is presented in the section «5.2.2
Transfer case», subsection «5.2.2.3 Transmission units control».
When the auxiliary power take-off operates for a long time, the bearings of the transfer
case primary shaft and those of the power take-off shaft should not overheat. Overheating indi-
cates some fault in the oil pump.
The pump working order should be checked by two persons as follows. To check pump-
ing action:
- pull the parking brake lever as far as it will go;
- set the transfer case lever to the neutral position;
- disengage the winch by lowering the lever on the frame r.h. side member;
- screw out plug in the pump body;
