93 Ford Explorer 4.0L with a vacuum leak.

[simi408]

i have a 93 expolrer with a 4.0 l auto transmition on the vacume sorce from the top of the rear of the engine there is a 6 port vacume sorce. the lines going to the brake booster, ac but on the vary front port is not covered. in some manuels it show i could go to the transmition. can any one help. i could have swarn that it was not conected to it at all. a couple of weeks a go when i started my truck i heard a big vacume leak
i found that port was uncovered. i pluged it with my finger and every thing was like before. i looked all under the under carage and the area right by the engine and there was no missing hoses or lose hoses. i dont know what to do and need help.
tanks
mike

 

[rileyrs]

i had this a while ago, just go to napa and buy a vac plug, and put it over the empty vac sourse on the tree.
i found later that that vac source was plugged, and i bumped off the plug while doin some seafoam.
but ya if there arent any loose hoses, just plug it

 

[BrooklynBay]

Welcome to this forum! I've renamed, and moved your thread to the stock 91-94 section. Check the line for signs of transmission fluid. A bad modulator could cause the vacuum line to get disconnected. It's possible that the vacuum cap could have dried up, and fallen off.