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final drive leak

nowing75

Senior Member
Joined
Aug 5, 2009
Messages
898
Location
coatesville indiana
Twice in 3 months i have had a peace of equipment that was siting in the shop overnight start leaking at the seal for the final drive. First time out t455 trencher unknown hours on the final but this last time on a 336d with 7200 hours on it. it was parked in the shop over the weekend and monday i pulled it out to move to a different bay and came in tuesday and lost maybe 1/2 a quart of oil. moved machine about a foot left sitting overnight and now no leak. Just wondering if anyone else ever has had this problem. Thanks

Jason
 

92U 3406

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Joined
Jan 3, 2017
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3,098
Location
Western Canuckistan
Occupation
Wrench Bender
Sounds like one of the duo cone rings cracked/broke and by moving the machine you put the break above the oil level. From what I've been told that can be caused by travelling with final drives forward and shock impacting them (ie driving fast off an RGN deck in cold temps or into a rock or stump at speed). Those duo cone rings are very brittle. An old tech once dropped an old one on the floor from waist height to prove it to me. It broke into about half a dozen pieces.

You won't know for sure what failed until you get it apart unfortunately.
 

Wytruckwrench

Senior Member
Joined
Jul 22, 2012
Messages
270
Location
Wyoming
Could it be pressure building from warming up?
Or as it warms up the O rings from the duo cone seals being stiff and causing a leak at a certain temperature, like a cat oil cooler leaking coolant.
 
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John C.

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Joined
Jun 11, 2007
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12,865
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Northwest
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Machinery & Equipment Appraiser
I've seen ice cause that more than once. Has the machine been in the cold for a long period of time?
 

nowing75

Senior Member
Joined
Aug 5, 2009
Messages
898
Location
coatesville indiana
It was in the shop over the weekend so everything should have been stable. No more leakage so going to send back in field and will check in it weekly.
 

willie59

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Joined
Dec 21, 2008
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13,361
Location
Knoxville TN
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Service Manager
Duo-cone seals are in my experience notorious for leaking with temperature differences and/or when they are a bit old and the silicone rubber Toric Rings have taken a set.

Ditto. And how many hours on those cone seals. One thing I learned by experience with crawler dump trucks was to tear down the final drives somewhere between 2K to 3K hours. Yes, pretty often one might say, but crawler dump trucks are only working when they're walking, wearing out those seals, and crawler dumps typically work in muck, that's their element. Let the cone seal go down on a Komatsu CD110R crawler dump and grenade the final drive, well, you're looking at about 24K to replace it. Me, tear it down and freshen up those cone seals. I wager the cone seal on that trencher is at the end of its life.
 
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