I need some help to understand what is happening with the a/c of my 1998 Ford Expedition; when it's parked the A/C works perfectly at any level; but when running, when acelerate over 40 miles/hr the A/C sounds like something is obstructing the ducts (air is still there but sound like obstructed); when remove the acceleration the A/C is back; so basically sounds obtructed only when accelerate. Any ideas?....Please advice Abraham_Hema@hotmail.com

I couldn't get my '98 Expedition out of park either and it turned out to be a recall part that had to be disconnected under the hood until I could get replaced!! Works fine now

Hi, this actually sounds like your heating system may lack vacuum. The system is designed to fail in the defrost mode. Some vehicles shut down ac compressor under heavy acceleration, but you did not mention heavy throttle.

So, look for vacuum leaks, you may need to install a vacuum reservoir. You may have engine performance issues, causing low manifold vacuum, you may have a check valve that failed, so under acceleration, the vacuum is not shut off, but rather evacuated into the engine...
Hope it helps....

If your oil level is good and this happened all of sudden, you probably have an oil pump going out.


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Replace the Air Ride System, with strutmasters or similar conventional shocks
Too old to put money into diagnosing and repairing another wet dream Ford had

I would start by checking the fluid level just to be sure it hasn't lost enough fluid so it can't engage the clutch packs. If the fluid level is good the you could have an electronic control problem that is preventing it from working but odds are that something mechanical inside the transmission has worn out or failed. A transmission repair shop can hook up the the controller and should be able to determine what has happened fairly quickly. If the problem is inside the transmission it may need to be removed to be repaired. Good luck with your problem, hope this helps out a bit!

you truly need to have it serviced and im sorry to have to say that however it could be a sensor or the transmission itself look for vacuum lines that may be rotted or a plug that had disconnected but this sounds like you need professional hands on repair

Input or output speed sensor,Incorrect fluid or fluid level,neutral safety switch,or TCM (transmission control module)

Gears are stripped.. On lower gears from riding the clutch.

Did they check it with engine at or above the 2500 rpm's?

Dear Customer,

This may happens,

parked from a long time on a same place,
oil level may be down,
you are trying on high speed RPM for shifting gear,

this what you have to do,
check you oil level & quility,

Try on your clutch activation point is it loose d or more tighten than also may happen,

Try to shift you car on low RPM with full clutch,

THNX