Spicer Single Drive Axles Service Manual: S170, S190, S590 - Manual (Page 9)

5
Inspection
Inspection
Make a Preliminary Investigation
These steps consist of external inspections and observations
that will be valuable when combined with the results of the
parts examination.
• Look for leaks, cracks or other damage that can
point to the cause of the failure.
• Make note of obvious leaks around plugs and seals.
A missing fill or drain plug would be an obvious
cause for concern.
• Look for cracks in the carrier housing (harder to see,
but sometimes visible).
• Does the general mechanical condition of the vehicle
indicate proper maintenance or are there signs of
neglect?
• Are the tires in good condition and do the sizes
match?
• If equipped with a torque-limiting device, is it work-
ing properly?
During the preliminary investigation, write down anything
out of the ordinary for later reference. Items that appear
insignificant now may take on more importance when the
subassemblies are torn down.
Prepare the Parts for Inspection
After the preliminary investigation, locate the failure and pre-
pare the part for examination. In carrier failure analysis, it may
be necessary to disassemble the unit.
• When disassembling subassemblies and parts, do
not clean the parts immediately since cleaning may
destroy some of the evidence.
• When tearing down the drive axle, do it in the recom-
mended manner. Minimize any further damage to the
unit.
• Ask more questions when examining the interior of
the carrier. Does the lubricant meet the manufacturer
specifications regarding quality, quantity and viscos-
ity? As soon as you have located the failed part, take
time to analyze the data.
Find the Cause of the Failure
Here begins the real challenge to determine the exact cause of
the failure. Keep in mind that there is no benefit to replacing a
failed part without determining the cause of the failure. For
example, after examining a failed part and finding that the fail-
ure is caused by a lack of lubrication, you must determine if
there was an external leak. Obviously, if there is an external
leak, just replacing the failed gear is not going to correct the
situation.
Another important consideration is to determine the specific
type of failure which can be a valuable indicator for the cause
of failure. The following pages show different types of failures
and possible causes. Use this as a guide in determining types
of failures and to correct problems.
Correct the Cause of the Problem
Once the cause of the problem has been determined, refer to
the appropriate service manual to perform the repairs.