I have a bit more information on this aux. gearbox. It may not have been marketed as a Chelsea, but maybe a Dana or Spicer. This box is not for heavy truck use, but maybe pick-ups or motorhomes. It weighs about 70 lbs. with a body of cast aluminum. I think it is probably about 25% overdriven. I do have a model number which is: 4800 074 133. Can anyone help with more specific information and maybe original manuals and set-up information?
Al
Alan