kenworth 2007 13 speed won't shift from low to high

you should hear a momentary bit of air , then it should stop. but a constant hiss means something is wrong.

sometimes on a new part the assembly becomes quite sticky and it will cause the new plunger to hang up. sounds like the case here, or something is impeding it moving.

 

1- completely drain your air system
2- take top cover off, should be held down by 2 screws - on my truck they are those 6 point stars
3-your red splitter will be sitting on top of the face of it - under that - on the right side (looking down at it) - will have 2 rubber gasket like pieces - don't loose these - and on the left side under the red splitter there will be a small hole where the ball bearing sits on top of - and the oval piece with the groove in it (groove side faces down) - there is a special spot for it to fit in the red piece. Put it all back together very carefully and screw the top down very tightly. start the truck and let it build air and this should solve your problem.

JUST DON'T LOOSE ANY PIECES!

good luck and let us know how it goes

 

Added about the spring, that thing is known for flying off if you are not aware of it being there.

 

well start taking it apart and let us know what you find. It may be another problem, I thought if there was no air pressure it would default to high range, maybe 13 defaults to low range? Someone know?

 

That is known as the plunger, the red one is the splitter.

 

Mine was missing the spring ... good to know though

 

What box are you talking about? One of the ones that are mounted to the transmission?