A To completely change the transmission fluid, the old fluid must be exchanged for fresh fluid by some type of pumping action, because most of the fluid is in the torque converter rather than the transmission pan. The best method is an exchange of fluid through the transmission cooler lines connected to the radiator. Connecting these two lines to a transmission flush machine allows the vehicle's transmission fluid pump, with the engine running, to pump out all of the old fluid while the machine pumps in fresh fluid at the same rate. This is a quick, easy and clean method for a complete transmission fluid flush and refill, and it's the service I would recommend for your truck. If the transmission filter has not yet been changed, it should be done with this service and requires removal of the transmission pan.
I know this sounds excessive, but I like the idea of draining and removing the pan, replacing the filter, refilling the transmission and then fully exchanging the fluid.
Changing the fluid by drawing it out of the dipstick tube would not exchange all the fluid and would not allow inspecting for debris, cleaning the pan and replacing the filter.
As for cost, my Alldata database shows one hour of labor to change the filter.
Q My 1999 Chrysler 300M with only 38,000 miles doesn't start easily anymore. I have a newer battery, and it's fully charged. I can twist and turn the steering wheel or play with the transmission shifter and then it may start. But if I just turn the key while in park ... nothing. It feels like something isn't making a connection. Previously the steering wheel locked with no movement once the ignition was turned off in park, but now it appears it doesn't lock. Might this affect the starting problem?
A Yes. Apparently the brake/shift interlock isn't functioning correctly. Because the steering wheel no longer locks properly, the problem is likely in the steering column ignition lock housing. The vehicle is equipped with air bags, so leave this repair to a professional.
Q We purchased a new 1996 Chrysler Town & Country minivan that now has 165,000 miles and has been at my mechanic's garage for two months. The problem is the headlights come on at random, whether the motor is running or not. The first time it did this, I could not shut them off. My mechanic got a used BCM and installed it, but this wasn't the answer. Any ideas?
A I'd focus more on the headlight switch and headlight relay than any electronic component. Remember, the headlights can be switched on even without the key in the "on" position. When the headlight switch is turned on, the switch provides a ground connection from the BCM (body control module) through the multifunction switch to the coil side of the headlight relay. Once the relay is engaged by grounding, direct battery power is provided to the headlight fuses.
The BCM helps control high or low beams and headlight time delay, but I suspect a circuit, wiring or connection problem is intermittently allowing the relay to ground, turning on the headlights.