This (photo attached) is on top of the transmission about 4 inches from the back. It appears to be some type of vacuum intake.

 

i think it is a vent tube.

 

its a vent tube usually plugged iirc

 

iirc..?..If it is a vent tube, what's it supposed to vent. And is it possible to get moisture into it because my manual transmission is slipping because of moisture in tranny oil.

 

It vents the transmission. When there is a temperature changes in the tranny it will suck or push air in or out. It could let water in, are you going through any deep puddles? thats why people extend the breathers on their differentials, does the same thing.

 

Yup, I do have to go through some pretty big water holes here in the Smokies. So maybe running a vacuum line higher up towards my engine compartment may solve my prob?