Transmission in wrong gear

[TownCars1]

I am noticing more and more that my transmission is keeping itself in a very low gear at the wrong times. It was a rare occurrence when I first got the car a few months ago, but it's getting much more common.

Most of the time when I start off, the transmission shifts normally between 2K and 3K RPM depending on how I heavy I am with the accelerator. But more and more, it's shifting and staying in 3rd or overdrive, and not letting the engine get over 1K RPM. It's still very driveable, but it has the acceleration of an early Geo Metro. I don't notice the engine bogging, it's just in the wrong gear.

Also, when cruising on the surface roads or freeway, it won't always downshift as I give it more gas unless I turn off overdrive, so acceleration is also pathetic during those times.

The car now has 108K miles. The transmission level is good, and I bought a new filter with gaskets in prep to change the fluid -- so that's already on the table.

Anything else I should be looking at with these symptoms?

 

[Town]

The 2006 needed at least 1 PCM update for throttle tip in and shifting to align with the 2007 PCM programming. Do you know if your car received the update? Your symptoms sound like the PCM programming of the transmission control system or perhaps some sticky solenoids. As a car ages the response from mechanical parts changes so there is always a reflash at a Ford dealer to compensate for wear. When the oil gets dirty from clutch dust held in suspension it will have an effect on the valve body and general transmission health. It cannot always be seen, but at 100,000 miles your trans fluid is due for replacement. I will look up the diagnostics to get a more comprehensive professional assessment later.

When dropping the pan, the frame members get in the way and you will likely dump some oil into the frame and have a drip for a long time. So best to pump or siphon a few quarts of oil out, or remove the rubber part of the cooler line near the rad and start the engine to pump out a few quarts. You will need an assistant to turn off the engine when the flow is still good but you have 2 to 3 quarts in a measured container. The pan should hold about 5 quarts.

Good luck.

 

[TownCars1]

Thanks for the reply, Town!

There's nothing in the service history showing a reflash of the PCM unfortunately, so I will have to assume it did not get it.

I'll definitely take advice on the transmission fluid change.

 

[Town]

A Ford dealer can check their system with your VIN to see if the TSB was carried out.

Attached are the diagnostics and some procedures on changing the trans fluid etc. You will want to change the filter. Unfortunately your torque converter does not have a drain plug so a pan drop is only going to change 5 quarts of the 13 quarts in the system. You can do a trans flush by running the engine to pump fluid out the trans line and refilling the pan through the fill tube. I have a draft procedure (authored by Mark95man at Lincolns on line) that I helped him with and that has been used a few times. I will find it and post it in pdf form.

Good luck.

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[TownCars1]

Thanks a million! I will be planning my attack carefully for an upcoming weekend project, as I would like to change the coolant, power steering, and axle fluids at the same time since I'll already be getting dirty.

 

[Town]

As promised, attached is the draft procedure to flush the trans oil on your 2006 Lincoln Town Car. This is the procedure that I will be using next year when I flush the trans for the second time. You will need to put 13 quarts of fluid into the pan in successive fill and drain passes to flush the oil out through the main pump, torque converter to the cooling lines and drain into container. This will not replace 100% of the fluid because the main pump will overflow some fluid into the pan instead of the torque converter and out the cooling lines, but you will get about 98% of fluid changed.

The procedure to get 100% fluid change is to supply the new fluid directly to the pump input tube at the filter and allow for excess fluid to drop from the open valve body etc to a catch pan while the majority of fluid is pumped through to the cooling line after the oil-to-air cooler. That is a very difficult process for DIY.

Good luck.

 

[TownCars1]

Thanks!

What would happen if after dropping the pan and changing the filter and putting the pan back, I followed those instructions and put the line going to the transmission cooler from the transmission into an empty gallon jug under the car, but then added a hose where the other one came off going into the transmission cooler into a gallon jug above the engine filled with fresh Mercon V, and then ran the car to effectively do a transfusion through the whole system including the transmission cooler?

Does all of the fluid flow through the trans cooler or only a portion? If it's only a portion, I would need to run more through there than just the fill capacity.

 

[Town]

There is a thermostat at the cooler assembly. When the oil is cool the thermostat directs the oil back to the trans, and when hot the thermostat directs the flow through the cooler. So there is always flow through the cooler lines, but not always through the actual cooler.

If I understand your proposal correctly then the gallon jug of Mercon V mounted high above the engine would connect to the fitting that the hose (to drain the oil from the trans) was attached to. The result would be a relatively fast flow from the trans to the drain jug and a relatively very slow gravity feed back into the trans. I think the trans would run out of oil in less that 20 seconds based upon MARK95MAN's estimate of trans cooler line output volume of 3 quarts in 8 seconds, and Ford's estimate of a pan drop as 5 quarts. Since the return line to the trans just delivers oil to the pan, there is no suction effect to increase the gravity flow from the jug above the engine. A 3/8" ID line over many feet is going to be a significant restriction to the gravity flow. You would be better off pouring the oil into the fill tube since there would be less restriction, but don't try keeping up with the trans pump and torque converter output volume that way either.

I think it would be a lot safer and easier to flush the trans in 3 quart stages as MARK95MAN says where you are in control and there is no risk of the trans running out of oil:

1. Drain the first 3 quarts through the cooler line hose and stop engine, drop the pan to drain remaining 2 quarts and clean it and replace the filter and replace the pan and torque it;
2. add 5 quarts, run the engine to drain 3 quarts then stop engine;
3. add 3 quarts and run the engine to drain another 3 quarts then stop engine;
4. add 3 quarts and run the engine to drain last of old 3 quarts then stop engine;
5. add 3 quarts and check oil level is just at the bottom of the crosshatched area with the engine running, adjust if lower.
6. take your car for a 15 to 20 minute drive in town and check the oil level and top up as necessary.

Steps 1 through 4 would drain 14 quarts, while steps 2 through 5 will add 14 quarts. Step 6 will adjust for the cooler lines being filled and oil expansion due to tempaerature.

Good luck.

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[Town]

TownCars1,

You mentioned earlier that you wanted to change the Power steering fluid. The 2006 model factory spec is Mercon, but this was discontinued in 2007 and replaced by Mercon V in most applications except transfer cases. The 2007 power steering fluid spec is Mercon V with the same power steering system as the 2006.

The procedures for changing the power steering fluid are attached, along with the description of the power steering reservoir so you will know the hoses to use. The power steering filling would only be required when the pump or rack or cooler needed replacement, but I included it for completeness. Similarly the power steering purge procedure would only be necessary to remove air in the system that should not happen with a flush. I am surprised that the procedure calls for a running engine since the flow will send fluid 20 ft away usually. I disconnected the engine ign to use the starter motor or a momentary switch (to avoid ign disconnect) to turn the starter. That had enough force to change the fluid on older cars easily.

Since the system holds about a quart or two at max an alternative procedure is to use a turkey baster or equivalent to remove the oil in the reservoir down to the return hose point and fill with new Mercon V. You will need to do this periodically but you will get the fluid clean. Check the starting colour and any particles in suspension as a control to when the system is clean.

Good luck.

 

[TownCars1]

Big thanks, Town! Yes, I am gearing up for these projects this weekend. I am hoping I can get the coolant, power steering, transmission, and axle fluids all changed this weekend. I have already done brake fluid, engine, and A/C service, so that will be all of them for a while.