Packard Forum Index » V-8 (1955-56)

Often when I start out in H on my 56 Patrician,the car has no power.The engine revs but the car moves out very slowly.Once in motion, everything seems to clear up and then it performs normally.If I put it in neutral at a long light and back into H, I get the same thing-not all of the time but better than 50%.Another issue is shuddering on hard acceleration.It goes away after a few seconds but is most disconcerting.Drive shaft etc have been checked and all appears to be OK.It has been suggested that my bands may need adjustment.Any thoughts.

No bands are in use when in H, so we can rule that out.

Its possible that the high range clutches are just about gone and are slipping on takeoff, but usually when they start to let go they never grip firmly again, and consequently things would not get better once underway--they would let go again on hills, for example.

The symptoms you describe sound very much like a slipping reactor clutch in the torque convertor. This is rather rare, as usually they seize and cause rapid overheating. But if it slips, the torque convertor becomes massively inefficient on accleration and the car will only ease forward with the engine revving wildly. If you ever get it up to speed, the direct drive clutch will engage. This bypasses the action of the torque convertor and the car feels "normal". The shudder on accleration may be the reactor clutch repeatedly grabbing and letting go. Rare, but possible.

Anyway, the only cure is to rebuild the convertor. And while you had it that far down, it would be pound foolish not to go through the entire tranny.

"H" selection disables low gear from engageing. So when the car takes off from a standing stop it is taking off in high gear or so called 'converter high". The sluggishness u describe is to be expected.

Use "D" for normal low/2nd/high shift ranges.

I bought my 56 Executive some 12 years ago with ORIGINAL 34K miles. It had some shudder and chatter that was somewhat sparce and intermittent. Usualy in cold weather. The symptoms have now stopped completely and had stopped at about 44K miles.

Never had the trans out or apart. Very early after buying the car i put Dexron ATF in the trans and now run the the more universal Dexron/Mercon ATF. Some do not recommend the Dexron/Mercon ATF. It's worked just fine for me now for 12 years and 22K miles.

Based on your explanation i would just try to drive the car for 5k OR 10k MILES to see if the problems work themselves out. Most likely the car has set for a long time without runnning?????????????

Several of your no/slow move symptoms are mentioned in the service manual as possibly being caused by sticking valves.

Ross mentioned the converter as possible issue on the shudder but manual also mentions dragging or tight bands. That could also be caused if valves were sticking & pistons couldn't release properly.

At the very least a fresh fluid change sounds in order and possibly even dropping the pan and seeing if there is a lot of sediment or debris from somewhere.

Eric swore by the B&M trick shift as curing a lot of problems but I can't speak from experience there.

GTO -

I certainly wouldn't expect the car to launch like a rocket in "H", but slipping in high range suggests that clutch pack is not fully engaged. Since this eventually passes, I'd look for a pressure problem.

Yet, even before going to the trouble of a pressure test, I'd change the fluid - including draining the converter.

Transmissions, as well as engines, that have been inactive for extended periods seem to develop varnish deposits in the darndest places. Fluid change and driving the car a bit may help clear that up.

Let us know how you make out with that.

I agree with a full fluid change, but also, based on the shop manual's comment about dragging bands resulting in shudder, I'd do a band adjustment - it's extremely simple. These things are simple and quick - if they don't result in improvement you can always go further but this particular transmission was rebuilt with a new (I believe it was an NOS) torque converter not many miles ago.

Have you checked the fluid level? I have a '66 Caddy that has a trans leak. If the fluid gets too low, it creeps in reverse until I "gun" it for bit then it shifts. If I keep it full, it doesn't do that.