Packard Forum Index » General

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.

IMO there might be two valid reasons to drop the pan. Cleaning the screen is a given but a visual check of things and the amount of sediment in the pan to make sure all is as good as the lack of symptoms suggest might be worthwhile.

The tightness of a couple of things should be examined. The screw holding the pot metal manual valve operating lever to the shaft has a known problem of loosening up and the small pin holding the valve link to that lever has been known to loosen and drop out. Checking the condition of both items might avoid a future surprise.

I can't think of a single reason not to do some incredibly overdue maintenance. Drop the pan, clean it and clean the inlet screen, and refill with Type F or Type FA. There is really no downside to this other than your labor and cost of the fluid. Then asses the transmission performance and decide where to go from there.

Just FYI, myself an many others who have had the groaning clutch have driven thousands of miles like that by doing just what you're doing, namely letting up on the gas and taking the load off as you anticipate the clutch engagement.

In some previous discussions, it came out that Ultramatics work best on B&M's special fluid. It even cures certain problems. I don't recall all the details, maybe someone with experience will chime in.

There is a service bulletin for the Twin-Ultramatic recommending friction modifiers. They act to increase clutch engagement a few milliseconds to produce smoother shifts. These might help reduce the DD chatter.

I think a better use of your car would be to draw a sample from the trans and send it for analysis. Any diesel shop can do that for you.

If the color is good and the report is good the only reason to change it would be to switch to modern Dexron.

Whatever is in the pan is going to stay there. The recommended change interval is 25,000 miles. If the car has only gone 10,000 miles in the last 40 years there isn't much reason to change it.

B&M Trick Shift is I believe the product Rusty referenced. Some folks have reported improvements in clutch engagement with it, others note no real improvement but it may be worth a try. I've read that its modified to contain a rosin to improve "stickiness".

While we were enjoying a rainy day outside the garage, I did take down the pan. The only problem noted, and the probable reason for the new leak, was a broken cork pan gasket in two places, possibly aggravated by my re-torquing the bolts. The drained fluid of uncertain vintage still looked red (but darker than new) and did not smell burnt. Just a touch of mild slime in the pan, much less than I'm used to with GM automatics. All looked clean around the untouched valve bodies. The one observation with regard to the valve lever and pin was that mine now has one of those bifurcated split pins as the rod connector. So maybe the transmission has been opened sometime in the past. The screen, once I figured out how to remove it, also looked clean, but was cleaned again for the next 45 years. Put it all back together, meaning than I'm down to four NOS cork pan gaskets left, and hope to have a dry day sometime soon to do a test drive.

I did not get around to adding any of that "miracle" Lucas transmission additive because I followed the Service Manual's instructions on refilling. Full mark came up sooner than anticipated. So I may still have some old fluid hiding somewhere beyond the valve body and converter. Once I drive it on dry roads, I will determine if I should drain about 20 ounces of Type F out of the pan (oh how I wish modern, non-Allison GM transmissions had a drain plug) and add the Lucas stuff. All in all, a dropped pan (after 45 years or more?) yielded no unpleasant surprises.

Did you drain the torque converter? This requires removing the lower bell housing and removing two plugs, they are 180 deg. apart. If not, you now have a mixture of old and new fluid. This is probably why the transmission filled up with so little fluid. If it was my Packard, I would go back and do a complete transmission drain. No need to remove the pan this time.

(o{}o)

If you have a 56 as the picture indicates, then just remove the inspection plate held on by two small bolts. Now you have access to the two plugs that are 180 apart.

Good catch, Randy. I was going to mention that the V-8s have a plate that can be removed, but the thought got lost somewhere. Thanks.

(o{}o)