Transmission drops out of gear at stops

[kkrofft]

Picked up a used '96 Taurus 3.0U, 122Kmiles with the AX4N trans. Guy told me he was getting rid of it because of trans issues. I drove it for a week with no problems but over the weekend it started to act up in the manner he had described.

When I put it in gear it will start forward but immediately drop out of gear (engine revs freely) If I apply throttle just as the trans engages it will move as usual and drives fine until I drop below 5 or 10mph then it disengages again. I shift into neutral then back to OD and apply throttle quickly and off I go again till the next stop.

Previous owner says he changed the fluid and filter and the fluid looks clean.
So what am I looking at? Shift solenoid? Trans controller? ???

Thanks!

[shorod]

Welcome to the forum!

Have you confirmed the transmission fluid level is correct (engine hot idling in Park when checking level)? Also do you know if the fluid was changed with the correct specification? Was the fluid and filter changed in an attempt to fix this issue, or the issue started shortly after the fluid and filter change?

-Rod

[kkrofft]

Originally Posted by shorod

Welcome to the forum!

Have you confirmed the transmission fluid level is correct (engine hot idling in Park when checking level)? Also do you know if the fluid was changed with the correct specification? Was the fluid and filter changed in an attempt to fix this issue, or the issue started shortly after the fluid and filter change?

-Rod

Fluid and filter change was done to attempt to resolve the issue. Fluid level and type are correct.

Note that initially I suspected low fluid level or low pressure (pump or internal leak). I would expect in both cases that increasing RPM would raise the pressure enough to make it engage but once it drops out the only way to make it go is to take it out of gear and re-select a forward gear. I also would think that either of those causes would be permanent and the car would not have run OK during the last week.

[shorod]

You've now stepped beyond my ability with transmissions. Hopefully someone will be along shortly to offer more suggestions.

-Rod

[65comet]

I have heard of the case that the clutch packs sit in will sometimes crack and not keep all the fluid inside it at the proper pressure. Particles from the clutches will sometimes fill the crack, then later wash away. Or the differing speeds will change the pressure and low speed won't have enough to keep the clutches engaged after it is warmed up with the case leaking back into the rest of the trans. More than likely you're going to have to get a tranny guy to take a look.

[kkrofft]

Additional research shows that it is likely either really bad mechanically as mentioned, or a result of an issue with the TCC solenoid. I need to check the solenoid connector for corrosion and then may try replacing the solenoid which runs about $32.

I will report back when I know more.

[shorod]

The Torque Converter Clutch and associated solenoid should only come in to the picture when you are cruising at 35mph or higher. Or, if the TCC engages and fails to disengage as you slow, it can cause the engine to stall, but should not prevent the transmission from engaging from a stop.

-Rod

[drdisque]

What you are describing is the usual problem with the AX4S - warping of the forward clutch piston. If you have a U-code engine you probably have an AX4S, not an AX4N (AX4N vulcans were very rare and AFAIK, not even made in 1996).

Unfortunately it requires a transmission rebuild or replacement, so unless you feel like spending $2000+ on this car, give the junkyard a call and see what they'll give you for it and yet another Gen 3 taurus will meet its grim fate at the hands of a warped forward clutch piston.

[kkrofft]

Originally Posted by drdisque

What you are describing is the usual problem with the AX4S - warping of the forward clutch piston. If you have a U-code engine you probably have an AX4S, not an AX4N (AX4N vulcans were very rare and AFAIK, not even made in 1996).

Unfortunately it requires a transmission rebuild or replacement, so unless you feel like spending $2000+ on this car, give the junkyard a call and see what they'll give you for it and yet another Gen 3 taurus will meet its grim fate at the hands of a warped forward clutch piston.

Car is a U vin and the trans has AX4N stamped in the pan. From what I can tell this is not an uncommon combination in '96.

I found a good used trans for $350. I have the old one nearly out and with new ball joints, sway bar links and one new brake caliper and pads I should have less than $1200 in the car and have a good low mileage daily driver for the next few years.

[kkrofft]

So installed a used trans from a local yard over the weekend. Long job but not too tough. Worst part was removing the exhaust Y pipe. Damn near impossible to get to the rear manifold bolts.
Car is operating smoothly and I am pleased with the results. Trans cost $350 with 122k miles which coincidently matched up with the miles on the vehicle. I normally pass on extended warranties but the yard offers a 6 mo. parts and labor for $70. They will come pick up the car, replace the trans and return it to me if anything should go wrong in the next 6 months. Brought the total with tax to $449. Seems reasonable enough.

[drdisque]

Real good job!