Grand Marquis Trans Slipping
I've bought a '99 Grand Marquis with 65,000 from my father-in-law a few months ago. He didn't recall any problems with it, but at 83 he probably just didn't notice what was going on. The trans is slipping when going into overdrive under light acceleration. It doesn't slip every time, but it does happen several times per day. When it happens the slip will last maybe 1/2 second, just long enough that you can feel the car slow-down a bit and you can hear the engine rpm increase.
The local Mercury dealer describes the problem as "overdrive bans slipping". They can repair it for ~$2,000, but they recommend a Ford rebuilt trans for ~$2400.
At this point all I've done is had a fluid flush.
With your experience I'm hoping you guys can answer a few questions. First, what can I do to maximize the remaining life of the trans?
For example, I'm assuming it would help to turn-off over-drive. Is this correct? Assuming it is, is this a big help, since the problem is with the overdrive bans slipping?
Also, we have some long (1 minute) red lights around here. Would it help to shift into neutral at these, or whenever the car isn't moving for more than 20 - 30 seconds? Or does every shift just put more wear and tear on the bands?
Basically, is there anything I should do, or anything I should not do?
Second, any opinion on how much life is left in the trans? From these symptoms does it sound like this is in the early stages of failure or close to a complete failure? Any opinion if the problem is isolated to the overdrive bans, or are other bands likely to start having problems.
Thanks, I really do appreciate your help.