Carrier Bearing Failure:
The carrier assembly holds the planetary gears in the overdrive. The planetary gear system is what steps up your output shaft speed to give you an overdrive. In direct mode the planetary gears as a whole are locked to both the input and output shafts of the overdrive. Since they lock both shafts together with no overdrive the carrier and planets spin together. When you have overdrive the planetary carrier is locked to the case and is stopped. Power then flows thru the planet gears and steps up your output shaft speed . So in overdrive mode the bearing is not turning but in direct mode it is. Bearing noise will be heard in direct mode and not in overdrive if the bearing is failing. Sometimes it can be mistaken for a tire or rear end noise, so pay attention and see if the noise goes away in overdrive.This unit had a major carrier failure. The bearing got so bad that it seized and tried to walk the whole planetary right out of the front of the unit. When a unit gets bad like this one you will also loose reverse.

Here is an image of a bad carrier with a bearing that someone purchased from a bearing supply house.

Bearings with steel cages will not work under these conditions. Acceptable cages are made of brass, phenolic resin or Nylon. These cages will support the balls properly under the high speed.

GM Part Number Is: 14105940

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