Minor lubrication issue :)

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
Post Reply
Scott in NM
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 429
Joined: Sun Sep 28, 2003 8:04 pm
Location: Tijeras, NM
Contact:

Minor lubrication issue :)

Post by Scott in NM » Mon Jun 12, 2017 5:10 pm

Went to drain my front differential to change the oil and nothing came out. However, it seemed to be packed with grease. I'm thinking that when I lube the ball joints for the front tires, the grease is leaking through some broken seal and getting into the differential. The questions become: What bearing/seal/whatever do I need to replace? What damage may have been caused to the differential? Anything else I'm not thinking of? Any help appreciated.

Scott


Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Minor lubrication issue :)

Post by Joe Gopan » Mon Jun 12, 2017 5:51 pm

How often do you lube the steering knuckles.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

User avatar
g.keating
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 397
Joined: Sat Mar 15, 2003 10:30 am
Location:

Re: Minor lubrication issue :)

Post by g.keating » Mon Jun 12, 2017 7:17 pm

have you checked this differential's oil level before or changed it before thus knowing there was gear oil in it before now? Could a previous owner have just packed it with grease?

User avatar
dpcd67
G-General
G-General
Posts: 11809
Joined: Mon Jul 25, 2011 3:41 pm
Location: Iowa

Re: Minor lubrication issue :)

Post by dpcd67 » Mon Jun 12, 2017 8:07 pm

Highly unlikely; as in impossible; the grease won't migrate inwards enough to pack your ring and pinion gears with grease.. Clean and lube everything per your TM, run it for 50 miles, check levels, and report back.
U. S. Army 28 years.
Armor Branch

skyjeep50
G-Second Lieutenant
G-Second Lieutenant
Posts: 532
Joined: Mon Feb 12, 2007 8:11 am
Location: Illinois

Re: Minor lubrication issue :)

Post by skyjeep50 » Tue Jun 13, 2017 5:13 am

Since the steering knuckles have pipe plugs - but are supposed to be lubed with grease - maybe someone got the mistaken idea that the differentials were supposed to be greased. Bit of a stretch, I know. Running the diffs without gear oil could do damage for sure. Have you checked the rear differential? On each of my Jeep projects I've taken apart the axles and thoroughly washed out all of the old grease, oil, rust and dirt - amazing what accumulates over several decades of previous owner's absent maintenance. There is an inner seal in the axle tube next to the differential - look at the TM's and parts manuals. If you don't have a copy you can study them on-line or download them at www.willysmjeeps.com - they are in the "Downoads" section.

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Re: Minor lubrication issue :)

Post by Joe Gopan » Tue Jun 13, 2017 5:49 am

And a reminder, the only way the upper and lower steering knuckle bearings get lubed is by hand packing during the scheduled service.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

User avatar
dpcd67
G-General
G-General
Posts: 11809
Joined: Mon Jul 25, 2011 3:41 pm
Location: Iowa

Re: Minor lubrication issue :)

Post by dpcd67 » Tue Jun 13, 2017 6:52 am

Most likely this is what happened; your differential oil has never been checked and it has turned into black sludge that looks like grease. Flush it out and fill it up correctly and hopefully no damage has been done. They are pretty forgiving.
U. S. Army 28 years.
Armor Branch

Scott in NM
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 429
Joined: Sun Sep 28, 2003 8:04 pm
Location: Tijeras, NM
Contact:

Re: Minor lubrication issue :)

Post by Scott in NM » Wed Jun 14, 2017 5:59 am

OK, questions answered in order:
1. Rear differential has oil.
2. I've owned the jeep quite some time. Last time the diff got oil was years (oil, not grease), so perhaps possible mud, junk, etc got mixed in and made oil look like grease (VERY long shot, but nothing else makes much sense).
3. Have all the parts manuals. Can interpret them no problem, but there are always multiple possibilities when something is unusual, so taking a poll to see what is the most likely (to me it would be a seal, but still can't imagine grease migrating from the knuckle to the diff case.)
4. Steering knuckles get lubed at 1-2 times per year (jeep only gets maybe a thousand miles on it annually, usually trips of 20 miles or less but on a weekly basis). If out 4 wheeling, get lubed more often.

Will clean and refill, then see what happens. Thanks for the inputs guys!

Scott


Post Reply

Return to “M38 Technical Knowledge Base”

Who is online

Users browsing this forum: dpcd67, ODAddict and 38 guests