Transmission / Overdrive: noise in park and neutral

[pogo]

I have a 1955 Commander with A 250 trans. that makes a banging noise when revved up to around 1000-1500 rpm. It only does it in park and neutral it shifts as it should and quite. I changed the fluid and no change. Has anyone else run into this, or has any idea's what could be causing the problem, sometimes so violent the car shakes. pogo

[DieselJim]

Broken flex plate between engine and torque converter

[karterfred88]

The flex plate is the most likely cause, unfortunately only way to know for sure is to remove trans and torque converter to examine it-look for cracks at crank attaching bolts radiating outward.

[StudeRich]

If it is not the Flex Plate, the other possibility is a worn Sprag Unit (one-way clutch).

However, I don't see that shaking the Car like an out of Balance Torque Converter would do, because of a broken Flex Plate.

[bezhawk]

It is a problem with these transmissions when in neutral or park for the torque converter clutch, or pressure plate to bang. It sounds like it is engaging when it shouldn't. There was a recommendation for not revving the engine without load. Jerry Kurtz will know more about this.

[pogo]

I have checked the flex plate, it is good. I have not heard about the problem bezhawk mentioned but the way it is acting it makes sense to me. Thanks guys you were a great help.........

[pogo]

Do you know of a "fix" for that problem? How can I get in touch with Jerry Kurtz?

[2moredoors]

Here is a reply from in part Jerry from another posting;
"Please don't take your trans to a transmission shop, I have received several in a basket that local shops tore apart and weren't able to reassemble. There are also some special tools that are specific to the DG transmission that are needed for rebuilds. I have a rebuilt DG 250 M ......... or call me at 717 308 1800
Jerry Kurtz"
Hope he does not mind me reposting

[studegary]

Do not rev up the engine in neutral or park when attached to these DG transmissions. If it reaches the point where the torque convertor "locks up" you will have major problems.

[RockabillyRebel]

I'm having the same problem. A couple of days ago I had the left side picked up so I could get underneath to change the starter. I cranked it up before I let it down. SInce I'm also having a problem getting the engine to idle down it was revved pretty high. When I heard the "clunk" my brother noticed the drive tire (still in the air) turning. The selector was in park.

[studegary]

I'm having the same problem. A couple of days ago I had the left side picked up so I could get underneath to change the starter. I cranked it up before I let it down. SInce I'm also having a problem getting the engine to idle down it was revved pretty high. When I heard the "clunk" my brother noticed the drive tire (still in the air) turning. The selector was in park.

The original poster and I have exchanged a lot of information on this off the Forum. I answered him, but I prefer to do the communication on the Forum where others can also learn.

A quick summary - On these DG transmissions, there is a lock-up torque convertor. When going down the road, the lock-up provides more responsiveness and economy. The torque convertor lock-up is activated by centrifugal force that is dependent on RPM of the engine. When the transmission is rev'd up in neutral or low, the torque convertor thinks that the car is going down the road and locks up or attempts to lock up. This is why I have said time and time again that these DG transmissions should not be rev'd up in N or P.

Repair the carb. or linkage problem that is preventing proper idle.

[dynolou2]

I have a friend that has a trans shop in Seattle, one of the local classic car dealers had brought him a 55 Studebaker with a trans that needed a rebuild. After completion it was sent back to him because of the same problem, noise when reved up in neutral or park. Well after six months of fighting it , and THREE rebuilt torque converters, he called me. I used info that was given to me by forum members, that Studebaker had issued a service letter detailing info on that problem. It got me a steak dinner. Lou Cote

[GrumpyOne]

I have a 1955 Commander with A 250 trans. that makes a banging noise when revved up to around 1000-1500 rpm. It only does it in park and neutral it shifts as it should and quite. I changed the fluid and no change. Has anyone else run into this, or has any idea's what could be causing the problem, sometimes so violent the car shakes. pogo

The converter is locking up. Do not do this!

The converter should only lock up under a load such as driving...

[SN-60]

The '50-'55 Detroit Gear (Borg Warner Drive) (Studebaker Automatic Drive) automatic transmissions were at best a 'work in progress'. Much TLC needs to be used by anyone owning/operating a Studebaker equipped with one of these units.

[nels]

I have checked the flex plate, it is good. I have not heard about the problem bezhawk mentioned but the way it is acting it makes sense to me. Thanks guys you were a great help.........

The broken flex plate is not always easy to see under the car. It will crack then propagate. The crack becomes almost invisible until you pry the converter back and forth. Don't discount it unless you had it out and looked at it.