2003 Lincoln Town Car, is this a durable transmission and what can I do to prolong it's life, aside from a BAC (big-ass cooler)? Any comments welcome. Mr Hoelscher?
Well, Dick has pretty much covered it. The 4R70W is one of the best transmissions on the market. As Dick noted, I have one in my van. It turned 300,000 (mostly towing) miles just before my 3000 mile tow to Lincoln for Nationals this year. The trans was rebuilt at 240K miles because I was selling my shop and figured it was due. Since then, its been perfect. By the way, since moving up here to the eastern tip of West Virginia, every time I tow west from here, I cross the Appalachians. The stretch of I-68 across western Maryland includes about a dozen mountain passes that are 2000 ft+ climbs. The transmission in my van does it without fuss.
It should be fine in the Town Car. An aux cooler is always a good idea in warmer climates. Regular fluid changes is the best preventive measure. As Dick noted, when the fluid gets old, the converter clutch shudders. The fix is changing the fluid. The weak link inside the 4R70W is the band (used to apply 2nd gear) but is hardly problematic. I put the big band servo in mine and it shifts very firm in the 5400 lbs van when empty. The electronics are very reliable with the possible exception of the MLP (Manual Lever Position sensor). These can go bad with age/miles and cause odd shifting problems. Most common is it falling out of Overdrive at cruise or random downshifting. If you have any odd symptoms, replace the MLP with a Motorcraft unit to see if that solves the problem. These almost never set a DTC by the way. Oh, and by 2003 the converter drain plug was gone. Figure that a well maintained 4R70W should easily go 200K miles in a Town Car.