That's what is driving me nuts, I've got the vacuum hooked up, and it was working!

I gave up yesterday, my frustration was running too high. I'm going to go out again this morning.

The rough part is that this is my only transportation to work.

 

Well, you proved to yourself that you can do what you set out to do...and congratulations! To learn how to swim, one must first jump in the water...and you did.

I can't help you on automatics...I don't know much about the innards of 'em, just some of the externals.

xlt4wd90 has got you covered

 

I'm afraid I don't know much about automatics either, just that the older versions needed some kind of load signal to control their shifting.

And yes, congratulations on what you'e accomplished so far. I hope you're encouraged to do more.

 

Well I'm still stuck!

After hooking everything back up I still don't have D (drive) on the transmission. I can manually shift from low to 2nd but if I put it in D all I get is low.

I found a big vacuum connection that isn't hooked up and for the life of me I can't figure out where it goes.

Looking at the front of the engine it is approximately at 4:30. It comes off the manifold as a major vacuum supply that runs to the brake booster and it's a short nipple with four small fittings running off it. I've replaced the two on the left side okay but I noticed on the right side one is plugged and the other has had a hose pulled off it. The connections on the right side are slightly larger than the ones on the left. I tried just adding a short length of hose and plugging it to no avail.

Could this be the line that runs to my vacuum modulator on the transmission? I thought that one ran off the three way fitting on the firewall.

I'm going to post this in the transmission area as well. This is driving me nuts! I'm going to have to go to the junkyard to see if I can find something hooked up to see what it looks like.

I will try to add some pics when I get home from work tonight.

 

That would be a good place to get strong vacuum. The fitting on the firewall only works as well as the source from the intake it's connected to. If you can run all of your vacuum off of this tree fitting on the back of the intake it would be a more direct source.


But that fitting may also be not a tree at all and be a ported vacuum switch. In that case, I don't know what it's for.


I would prefer for my vacuum for the transmission to run off of the back of the intake.

 

First, is the fluid level on the trans up to par? Maybe a dirty filter and old ATF fluid?

How do you feel about dropping the pan and changing the (6 quarts) of ATF and filter?

I believe the modulator just controls the shift points.....The vacuum tree should go to the brake booster and modulator valve....PVC goes to the carb.

A cut'n'paste:
Assuming that you mean the vacuum for the trans... there will be a hard line between the engine and the transmission. It runs down the back of the engine and along the transmission's bellhousing and the case (the C6 just happens to have an integral bell and case, the C4 for example doesn't). It will connect at the engine to a brass tee fitting that's screwed into the intake or at another point that has direct intake manifold pressure such as a carb base or a fitting for a power brake booster. The other end leads down to the modulator that's screwed into the transmission case. There will be a soft flexible line between the hard line and the modulator, make sure it's not cracked or broken up because they get brittle over time. Also make sure that the hard line doesn't have any type of fluid in it and that it isn't clogged up with any gunk. Clean and blow it out with pressurized air if necessary. Do the same for the fitting at the intake manifold.

 

Just did a transmission service this summer. I've done three in the last two years cleaning out all the old gunk and such. I just found out how to drain the torque converter so next summer I will hit it again.

That being said I don't think that's the problem. Nothing was wrong transmission wise until I messed with the vacuum lines.

 

Ok....the link posted in #34 was of no help?

 

No, sorry. I have a TON more vacuum lines than posted. The 1986 5.8 4V HO was the last of the vacuum run motors, I think the Ford engineers ran our of space for more hoses and went to computer controlled engines

For the life of me I can't figure out what would just kill my transmission shifting like that, and that open port is maddening. I replaced lines on the other side of the vacuum Tee and the one open port is shiny like the hose was just pulled off. Will go bang my head against the wall again tonight.

 

Did you get some resolution?

 

Oh man did I get some resolution!

The ole spaghetti factory runs like a Swiss watch. No kidding, she runs like new.

I've got to finish hose replacement but I'm going to wait until I have money for new valve cover gaskets.

The idle won't come down to where it should be but I will wait till I finish with hose replacement before I worry about that any further.

 

Great! What made the biggest difference?

 

Sorry Justin I couldn't tell you.

I did a bunch of vacuum hose replacement, all the small stuff on the drivers side and some bigger stuff on the passengers side.

The greatest improvements have been in the return of the heater, it starts on the first try and stays running to warm up and runs smoothly while cold. Oh, and the brakes are like new!

So obviously everything was bad. As I stated I'm going to finish to get everything straightened out.

My best advice is to go down to Napa and buy $10 worth of good hose in the three sizes needed and start replacing one at a time, slowly and carefully.

Any issues I had like the transmission were because I did too many at one time and didn't get everything hooked back up the way it should be.

The 86 engines should be called Chef Boyardee there's so damn much spaghetti!