Cummins stator repairs

Member shares Cummins stator repairs

Many people are increasing performance on their diesel vehicles. Many Cummins converters are appearing with spring retainer failure. The spring retainer and outer race may have turned inside the casting. This article may be helpful to any torque converter rebuilder experiencing these issues.

Since members at Branting have been modifying stators on a CNC mill, they have had only few comebacks. Since these few problems have occurred, Branting has developed a few new ways to make them work. Take a few minutes to attach the spring retainer by brazing the spring retainer to the outer race, which will keep it from spinning.

To repair outer race spinning, whether you choose a CNC mill or Bridgeport-type mill, Branting recommends five 3/8” slots, evenly spaced, to be milled into the stator ID. Before pressing the race into the stator, you may choose to heat the stator using your clutch bonder, and additionally chilling the outer race in a freezer before the parts are assembled. Use may also use a lock tite-type product to permanently lock the race in place.

Another method of repair for this stator is to replace the outer race with a GM 300mm converter’s outer race. According to Mark Mustard at Branting, it is the same size and “drops right in.” You will have to add a .050 shim under the outer race. If you choose not to use the .050 shim, you will be required to shorten the inner race by .050. This is the preferred method by Mustard and rebuilder trying to “tighten” the converter.

Mark Mustard currently uses this modified stator in a 99 Dodge Cummins Diesel that produces 740 ft. lbs. of torque at 1600 RPMs, using an Edge chip on level 5. He reports
this modification has worked extremely well.

We thank Mark Mustard of Branting Industries for his suggestions. Use these suggestions after proper testing in your facility.

December, 2005 Newsletter