front axle in/out switch

[speedster]

New Guy here.

I just purchased a 1984 M923 the issue is the lock in/out switch in dash was leaking oil, not from the fittings . Replaced the switch with a new one. In less than 6 hours it started to leak!!!. Is there some part in the transfer case I should check???.

Love the truck I hauled explosives through the jungles during the Vet Nam war

Thanks

 

[Mack 121472]

Sounds like it is out of the air compresser not the switch , should only be air there. The air compresser seals are leakin oil in to the system some where to get to the switch.

 

[speedster]

I checked the air filter yesterday and at least a pint + came out when i pulled the cover. so i'm completely lost now

any help is is a boon

 

[rangereter]

Remove the fill/level plug on the transfer case and see if it is overfilled (with fuel contaminated gear oil)...this condition along with oily residue in the filter housing is the result of over filling the fuel tanks, allowing fuel to enter the air venting circuit (because of engine vacuum I think?) which terminates/dumps into the air filter housing. I doubt that your compressor is worn to the point that it is passing enough oil into the compressed air system to be seen coming out of the vent orifice of your t-case front axle lock valve. A worn compressor usually takes a month of sundays to build air pressure, and will pollute the entire air system with engine oil. It might be a good idea to check all gearboxes/axle housings that are tied in with the air vent circuit for fuel dilution.
Regards, Bob

 

[jonesal]

I had this same problem on my M35A2. It turned out to be a air leak into the transfercase causing the transfer case to become pressurized and forcing oil back up the air line to the switch. I overhauled the air shift piston and it fixed it. I have not traced a 5 ton, but isn't the line pressure zero when switched to off? I also know the M35s have a spring loaded vent that can become stuck causing pressurization. Is there a vent on the 5 ton transfer cases? I have not been able to find one on my M923.

Good luck.
AL Jones