1999 Ford Windstar SEL 3.8L automatic with about 130,000 km.
When engine is cold van goes into reverse no problems. Once van warms up and I put it into reverse I have to rev the RPM's to almost 3000 then it will slam into reverse. Once it does this once and I try reverse again I have to give the gas a quick tap to get it to rev to just over 1000 RPM's then it will go into reverse. Then after this it will go into reverse like it should without having to rev the engine. Once in reverse I can reverse forever if I wanted. I can also go from reverse to another gear to reverse with no problems at this point. Now if I drive a bit more and try reverse it is still there sometimes or I have to do the revving the engine process again to get reverse to work. After driving a while I do get the O/D off flashing in the instrument panel with message Check Transmission. The code I get is P0713 Transmission Fluid Temperature sensor A Circuit High Output. The transmission fluid is at proper levels and looks clean and smells normal. I did change the transmission filter and replaced the fluid that came out. I also changed the transmission range sensor (neutral safety switch) I brought it to a local transmission shop and after 20 minutes they said it needed a new transmission. Not sure I believe this completely, thinking/hoping its electrical. I asked the trans shop about the computer code and they said it didn't mean anything. Yesterday while driving home the transmission just seemed to cut out or disengage. The van never stalled, it just wouldn't move. Didn't lose power steering or power breaks just the transmission. No overheating or warning lights. Shut van off for a few minutes, started it back up and it drove home fine. Any help or tips or ways to diagnose or even diagnostic tests I could ask to have done would be great. Thanks

 

Sometimes the sensors are corroded. It is certainly worth checking that first before declaring the transmission shot.

 

Today I thought I would check the sensors I could get to. First thing I did after disconnecting battery was to disconnect the main wiring harness going into the valve body of the transmission next to the neutral safety switch on top of transmission. I noticed that there was what appeared to be transmission fluid in the plastic female end of the connector going into the valve body. I am thinking that this may have something to do with my problem. Fluid in an electrical connection cannot be good right?
Not sure what could have caused this. Could the trans fluid have raised or built up too much pressure somehow and forced its way out through this connection? Could this damage PCM or other components? Is there something in valve body that could have done this? Could faulty TFT sensor cause this or maybe other way around.
Any help or suggestions greatly appreciated.
Thanks

 

I would try to replace the valve body on it and should be okay. the pcm is internally protected and shouldn't be a problem. that will most likely stop the reving of the motor to get it go into reverse.

 

Valve body sounds logical to me also. Had a 94 Sable LTS that would hammer into grear when shifting from P-R, P-D, D-R and R-D. Would swear that the tranny was going to blow its guts all over the ground. Replaced the valve body and all shifting went back to normal shifting before the hammering. Good luck.

 

I don't recall where I found this but I thought it is worthwhile to keep:

AX4N transmission repair


Symptoms: My 96 AX4N transmission would hesitate engaging at a stop sign and eventually completely failed with no forward or reverse gears. There was absolutely no engagement, so the clutch pack was not suspected as a problem.

Diagnosis: Before I did anything else, I checked to see if the pump was working (based on telephone advise from a helpful tranny shop). With the car cold and NOT running, I checked the tranny fluid and made note of how high on the dipstick it was (it should be VERY high). I wiped the dipstick off, but did not replace it yet. I then started the car and inserted the dipstick back in within 10 seconds, and rechecked the level. Since the level dropped, I thought the pump was working. Actually, I think if I had re-checked the level when the engine was warm I would have found the level to still be high (I later discovered the pump had failed).

I next towed the car to an AAMCO shop that read the computer tranny codes at no charge. He came up with three codes indicating incorrect gear ratios and a fourth code (the root-cause code) indicating that the torque converter control valve was stuck.

The technician (very helpful) suggested that the retaining clip on the control valve was broken, and this caused the valve to get stuck. This is apparently a common problem because the valve slams into the retaining clip fairly hard. He then took me down to the repair area and showed me an AX4N valve body, the location of the control valve, and what the retaining clip looked like.

Research: Before I began, I went to the library and accessed the "AllData" web site. This is a mechanic's resource site with a very expensive subscription, but my library provides it for free. I located the procedure for removing the pump and valve body from a Taurus. The procedure was not very clear, but it did show a drawing of what bolts need to be removed. (I have a better picture shown below though).

I also checked out a copy of the Haynes manual (not Chilton) for the Taurus. It doesn't describe how to remove the valve body, but it did show me how to remove the motor mount and sub-frame. However, it failed to tell me I needed to remove the main cross member (neither did AllData).

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Postscript After posting this and re-reading it, I realized that the rest of this discussion seems one-dimensional. What you should note is that most of the AX4N tranny problems are related to the valve body. The same procedure and discussion is useful for ANY valve body problem even though mine was the pump. Getting the valve body out of the tranny is $1800 worth of the total repair!
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Final Cause: It wasn't until after I got the car apart that I discovered the real cause of my problem. All of the symptoms pointed to the control valve. However, I discovered that the pump shaft had sheered and the pump was fouled up with metal pieces. There was enough friction between the two halves of the broken shaft to make the pump turn slightly, and this is why I didn't detect it earlier.

Inside the pump are two guide rings. These broke and the metal pieces were trapped inside the pump body. The pump would still function properly under high RPM even without these rings. However, at some point the metal pieces jammed into the vanes and seized the pump. This caused the pump shaft to sheer off. The inset photo is an Internet picture of what the pump is supposed to look like.


Repair Options: For $200 I could get new pump parts, but there is a risk that metal got into the solenoids (which are electromagnets). Or for about the same price, I could get a complete valve body and pump at a junkyard. I chose the junkyard. (The junkyard would have provided a completely rebuilt valve body for $350.)

Tools:
When I took on this project, I assumed that with the $2000 savings I could buy some additional tools. I bought a bunch of tools, but the ones listed below are what I really needed.

Metric socket set with a wide variety of extensions and universal joints.
Air ratchet is helpful but not required.
Impact wrench with metric sockets.