89Tonka

So I have an '89 F-150 with the 5.8L 351W in it. I recently had to replace my valve cover gaskets and while doing that I went ahead and cleaned out the throttle body, upper intake manifold (while removed), replaced my plugs and wires, replaced my PCV valve and reconnected (it had been running without it for the last year since I bought it), now today I hook everything back up and the engince sounds great at first but then starts to choke out. I think I may have some of the vacuum lines mixed but my diagram doesn't give a very clear picture and my chiltons skips my model and year (same with the electrical connections diagram) but that's not the worst of it. I went to drive it down the road and the transmission (automatic) is not going into gear, nothing happens when you try or it might catch for a second when you step on the gas but then it it disengages. I'm thinking this is vacuum related if someone could point me in the right direction I would appreciate it.

transmaster

I assume you have a C6,or perhaps an AOD, if so it does sound like you have pulled the vacuum line off of the modulator valve. I am not sure where the line comes up from the transmission on your model year but you should be able to see it at the back of the engine, there will be a short piece of vacuum line going from the hard line to the vacuum fitting on the intake manifold. I had this same thing happen on a 78 Mercury Cougar, it had an FMX on it and with this vacuum line pulled loose it didn't shift right at all, once I figured it out is took longer to open the hood then too fix it by reconnecting the rubber vacuum line.

89Tonka

Thanks for your time I'm about to go start digging around under there again been trying to find a more detailed and simple vacuum diagram but no luck finding one online and my chiltons has diagrams for every other year and model but skips mine for some reason. Guess I'll just start following trails untill something doesnt look right. Thanks again for your time

Good old Bill

Somewhere around your vintage I believe the modulator was replaced by another system. Just in case I'm wrong, crawl under truck and at the rear of the trans above the pan is where the modulator was located. Think is was passenger side.

transmaster

I looked up the part all all part outlets list a vacuum modulator and a C-6 for
1989.