# allison 545 myserious oil leak



## wookie (Jul 13, 2010)

trans oil leal only happens when truck is moving. sitting idling or in gear-no leak! changed trans lines and put in new pan gasket(twice). cant find leak! its bad too. about 4 litres per day.any one had this experience. The dealer wants to put in a new trans.


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## dbarton291 (Jul 14, 2010)

RE: allison 545 myserious oil leak



> wookie - 7/13/2010  10:16 PM
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> trans oil leal only happens when truck is moving. sitting idling or in gear-no leak! changed trans lines and put in new pan gasket(twice). cant find leak! its bad too. about 4 litres per day.any one had this experience. The dealer wants to put in a new trans.



Is this a gasoline engine?

Is there any evidence of transmission fluid under, or on the underside of the vehicle?


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## SuperMike (Jul 14, 2010)

RE: allison 545 myserious oil leak



Surely there must be evidence of a leak. 4 Lires is getting on for a gallon, that would make one hell of a mess.


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## H2H1 (Jul 14, 2010)

Re: allison 545 myserious oil leak

WELL I DESCRIBE it as changing the fluid every day you drive it :laugh:  :laugh:  :laugh:


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## dbarton291 (Jul 14, 2010)

RE: allison 545 myserious oil leak



> SuperMike - 7/14/2010  12:36 PM
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> Surely there must be evidence of a leak. 4 Lires is getting on for a gallon, that would make one hell of a mess.



Unless it's a gas engine and the vacuum modulator has a broken diaphragm.  The oil gets sucked up the vacuum line and burned in the engine.


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## SuperMike (Jul 14, 2010)

RE: allison 545 myserious oil leak



> dbarton291 - 7/14/2010 10:40 PM
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Well,I learn something every day.

However would you not then have a smokey exhaust ?


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## dbarton291 (Jul 14, 2010)

RE: allison 545 myserious oil leak



> SuperMike - 7/14/2010  5:57 PM
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It may, particularly on deceleration when gas engine vacuum is high.  It will be white smoke usually.


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## C Nash (Jul 14, 2010)

Re: allison 545 myserious oil leak

If the undercarriage is not oiled all over it has to be sucked back through the engine.  I would think this amount you should be able to see white smoke with a little blue tint to it.  Let us know what you find.


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## dbarton291 (Jul 14, 2010)

Re: allison 545 myserious oil leak

If it's a diesel, is there a PTO on it?  Could be leaking through the PTO cover gasket or elsewhere in a PTO system.  ATs will also spew at highway speed out the breather if they are overfilled with oil.  If it's diesel, I would check the PTO system, or cover gasket, and the calibration of the dipstick.


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