3.1.0 PTO Maintenance
The power takeoff, being an integral part of the transmission, should be serviced at the
same intervals as the transmission. Transmission fluid changes should follow the
interval recommended by the vehicle manufacturer for severe service. Transmission oil
level is important. Checking for PTO leaks and checking the transmission oil level
should be done on a regular basis.
The PTO is also part of a system. The PTO system may include the activation control
parts, a driveshaft, or hydraulic pump. This PTO requires periodic checks and service.
Typically the interval for maintenance checks of the PTO system depends on the
application of the system. Every time the chassis is lubricated or a mechanic is under
the vehicle, the PTO system should be checked and serviced. For severe duty PTO
system applications, it is recommended that the system be checked for service every
100 hours of use. Service should include checking and lubricating direct mount pump
shaft connections. PTO gears can be checked for wear by removing the inspection or
shifter cover. If pitting, galling, cracking, or deformation of the gears has occurred, then
the PTO needs to be rebuilt or replaced.
After installing a new PTO or overhauling, recheck the PTO within the first week of use.
Check for leaks and loose mounting hardware such as studs, cap screws, and nuts.
Recheck the cable or lever connections for proper adjustment and tighten any loose
connections. At regular maintenance intervals, check adjustments, lubricate moving
parts, and tighten and repair the connections, mounting hardware, and cable or lever
linkages.
Pumps that are mounted directly to the PTO output require the application of an
antiseize or a high temperature, high pressure grease. The purpose of this grease is to
help make the PTO easier to service and to reduce the effects of fretting corrosion on
the mating PTO and pump shafts. PTO applications under severe duty cycles and/or
high torque requirements may require servicing this shaft connection, periodically re-
greasing the vibrations inherent in these vehicles. Fretting corrosion cannot be stopped
by applying grease; the grease is only a deterrent.
If the system utilizes a driveline between the PTO and another device and if you have
noise in your system that was not there before, the angularity or phasing of your
driveline may be the cause. Check driveline angularity and reduce total angularity per
the recommendation in
Figure 8-40
, and be sure the PTO shaft is parallel within 1.5° to
the pump shaft (or driven unit). Drivelines must be in phase, that is, the yoke ears on
the PTO and pump shafts must be in alignment;
Figure 8-41
provides a quick reference
for troubleshooting a power takeoff.
NAVEDTRA 14050A
8-47