OK so I finally got my manifolds replaced, smog pipe, and did spark plugs while the manifolds were off. Havent driven the truck in about a week or so and now that its all back together, the truck wont shift out of first gear!!

Im thinking this is either the transmission modulator or the vacumm line to it. My question...where does the trans modulator vacumm line connect to the engine? Cant find a vacuum diagram anywhere online.

 

The vac line should connect directly to the tree on the manifold (I'm fairly sure). Is there a line hanging loose? If you have a vac line missing or disconnected, the truck shouldn't run very well, even just in 1st gear.

 

Now that you say it, it is running a bit rough. Hmmm...thanks for the info. I'll check the manifold.

 

Maybe the line from the modulator got knocked off of a fitting (or at least pulled loose enough to lose vacuum) while you were wrenching on things. Is the vac line connected to the modulator? If so, just follow it to see where it goes. If not, there should be one coming off the manifold with the other end just dangling.

 

I don't think your truck has the vacuum modulator. You probably didn't hook up the TV cable or it is now out of adjustment when you reassembled it.

 

Hi Guys,
Was away for a bit but Im thinking Im gonna get working on the rig this weekend. Im pretty sure I have a modulator on my tranny. I didnt touch anything while I was wrenching on the manifolds and it shifted fine before that project. I'll need to do some more diagnostics...modulator and vac line is where I will start. Any other suggestions?