Hey guys, got a question here. Got my motor running after replacing the rockers, and rods. When taking it for a drive I noticed that it won't down shift. It's like she's stuck in first gear. I can shift into reverse, drive, everything and you can feel her slam into gear. Transfer case shifts and works fine. Could this be the result of a bad vacuum line causing the automatic trans sensor not telling it to downshift? No check engine light has come one either...yet.

89 F-250, 351w, C-6 auto, no o/d, 4x4

 

sorry to not answer sooner. ok, c6 has a metal vacum line that comes down on top of the trans, and ends at the back on the pass side.top rubber line should come off the upper plenum, and attach to the metal line. on the bottom, the rubber line comes off the metal, and goes to the modual. replace both ends. when you pull the line off the modual, see if trans fluid drips/runs out. if not, replace the rubber line, and test, if trans fluid found, post again, and I'll tell you how to fix that part.

 

OK, found the line and when I unpluged it from the modual and not fluid came out. found that it was still unhooked from the intake. Question. I'm not sure exactally where on the intake it should be pluged in though. Do you have apic that I could refer too???

 

Oh yea and the check engine light finally came on after running about 10 min.

 

right on top of the plenum, there is a bunch of hoses. 1 big one, that goes to the booster, and some small ones. red to fuel pressure reg, black to heater, black to trans, and black to emissions. might be another red one, I forget, and it's raining right now. vacuum leak will give a code, and make check engine light come on, pull the codes, and see what they are before you spend any money

 

Woo Hoo, Your the man Charlie! Hooked it up and trucks shifts just fine now. Thanks! Don't ask me how I missed that but I did.

 

cool. we keep this up, your going to have a new/old truck btw. other one goes to the map sensor

 

Is that something like a GPS????

 

Manifold Absolute Pressure sensor