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Splitter does not shift when cold on mack 12 speed

Terry Rinkes

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Not sure if this helps anything, but the range shift on the 15-speed Fuller I had did not want to shift when I first started the truck.  I had to sit there in neutral and flip the hi-lo several times to get it to shift.  Once it shifted, it was good for the rest of the day, even if it was cut off and restarted.  This was a lot more noticeable when it was cold, and nowhere near as pronounced when it was hot.

I believe I had a slave valve gummed up, preventing proper air flow to the shift cylinder.  That truck had a little oil in the air system, and I believe that oil was causing the slave valve to be stubborn.  These air-shifted puppies can be picky about clean/dry air.

"Eagles may soar, but weasels don't get sucked into jet engines."

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When your talking cold, what sort of temp are you talking

Cold in Australia is different than other places around the world 

As to the oil I cant advise if it's ok or not

I would check the air pressure and make sure the regulators are working correctly 

I would as check the filter and the exhaust to make sure it is clear



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