Transmission/AC problem???

[PoliSciGrl]

I have a 2001 Ford Windstar, 3.8L. Yesterday I two seemingly unrelated problems occured at the same time. My air conditioner quit getting cold and my transmission started acting up. When I accelerate from a stop, it makes a jerking motion, similar to when you start in second or third gear on a standard, only this is an automatic. Also, the tranny does not seem to be shifting up. It drives good from about 15-30 mph but then the rpm's start to go up. Today I changed the transmission fluid and filter. (No shavings in the fluid.) Any ideas on what could cause both of the sympoms, has anyone had a similar experience?

Thanks a bunch for any suggestions.

[wiswind]

I don't know what 1 problem would cause both symptoms.
It might be worth having a shop troubleshoot the A/C system.
One thing that you can try is to select a A/C setting, and verify that the compressor is engaging.
If the compressor engages momentarily, and then disengages.....then you could be low on refridgerant, or could have a defective sensor or switch.
If you are low on refridgerant, it will be due to a leak....which a competant shop will troubleshoot to find before replacing parts.

If the transmission starts to use only 1st and 2nd gear....that is "limp" mode.
A common cause of that is a defective Transmission Range Sensor (TRS).....which is also called "Neutral Safety Switch".

[PoliSciGrl]

Thanks wiswind - I am going to replace the TRS today (if I can find one). I find it hard to believe that I would be low on refridgerant because it was blowing just fine one minute and then not cold the next. Very odd. Will go through your suggestions though, but I believe I heard the compressor come on and stay on with the air on.

[wiswind]

One other thing that could be a factor with the A/C is the blend door.....
Others on here have much more experience with that than I do.....but the blend door can get hung up.
From the alldatadiy description.....all the air flows over the evaporator core....which will cool the air when the A/C system is operating.
Then the air flows by the blend door.....which is driven by a electric motor to be in a position that is controlled by the TEMPERATURE control knob on the dashboard.
At the coolest setting.....very little air will flow over the heater core.
At the warmest setting.....all the air will flow over the heater core.
The heater core is always hot......when the engine is warm.

To test to see if the blend door is a factor...once the engine is warmed up.......turn the A/C OFF.....and see if the air is HOT...which would indicate that it is flowing over the heater core.....now this is not just the heat of the outside or inside air...but hot as in heat from the heater.
IF it is NOT hot....then the blend door is not causing the problem.

[AdoptedBassist]

Originally Posted by wiswind

One other thing that could be a factor with the A/C is the blend door.....
Others on here have much more experience with that than I do.....but the blend door can get hung up.
From the alldatadiy description.....all the air flows over the evaporator core....which will cool the air when the A/C system is operating.
Then the air flows by the blend door.....which is driven by a electric motor to be in a position that is controlled by the TEMPERATURE control knob on the dashboard.
At the coolest setting.....very little air will flow over the heater core.
At the warmest setting.....all the air will flow over the heater core.
The heater core is always hot......when the engine is warm.

To test to see if the blend door is a factor...once the engine is warmed up.......turn the A/C OFF.....and see if the air is HOT...which would indicate that it is flowing over the heater core.....now this is not just the heat of the outside or inside air...but hot as in heat from the heater.
IF it is NOT hot....then the blend door is not causing the problem.

The blend door actuator is relatively easy to replace if needed. I had no heat and suspected the actuator but as it turns out it is a much more expensive problem - the 'air flow flap' inside my heater box has a broken shaft and will cost MUCH MULA to replace. I hope your issue is as simple as a faulty acuator. In the fall I am going to attemp a fix that will include a dremel tool! My best estimate to replace my heater box as it is now is $1000cdn! DOH! I LOVE MY FORD!