To drain or not?

Posted by Dave Brownell On 2014/7/19 12:08:23

We've got several days of rain predicted, the 56 Packard is up in the air in the garage, and worst of all, I am feeling a bit guilty and bored. The fellow who owned my car previously is a retired Chrysler mechanic (plus some GM) who says that in the 45 years that he owned it, the Ultramatic fluid has not been changed or the pan removed. Because of some slight leakage, top ups have been done with Type F, but until recently those leaks have been minor. The lock-up clutch may be dried out because unless you let up slightly on the gas right after the shift, chatter will happen. Backing off, just a bit, all seems fine in either H or D.

Another old friend, also an experienced retired Chrysler mechanic was agast when told that the pan had never been off or the fluid changed. He's obviously not a guy from the "Don't tempt fate by changing to new fluid" school, but believes in preventive transmission maintenance. He says change the fluid (including converter draining) and refill with fresh Type F, plus some Lucas-brand of miracle transmission stuff.

Since mechanic #1 (previous owner), the son and grandson of Packard dealer mechanics who left him a legacy of service books and notes, also sold the car with a trunk load of mostly NOS parts, including several pan gaskets, for the Ultramatic, I am tempted to drain, then drop the pan, wipe up whatever has accumulated in 45-58 years. Then put it all back together and hope that the fresh detergent properties of the new fluid don't do it in. Or should I leave well enough alone and look for something else to do?

I have searched the FAQs and have decided on the fluid type, but saw nothing much on additives or screen/filter cleaning-replacement. Certainly nothing on leaving well-enough alone.