Information on the Allison Transmission and retarder can be found here by opening the PDF file.

http://www.allisontransmission.com/p...s/OM3349EN.jsp

Here are some highlights that may prove of interest. With a retarder service intervals are cut in half. If you use Dextron you need to change fluids every year or 12,000 miles instead of 25,000. Transynd is impacted similarly, but has longer oil change intervals, depending on some other factors such as flilter types.

The retarder force will be reduced if the fluid overheats. I mispoke earlier. It appears that the computer will eliminate the need to worry about temperatures.

Speaking of temperatures: they vary depending on where the temperature reading is taken. The sump oil temperature maximum is 250 degrees F. More details are available at the link above.

Instead of having to take the bus to Allison to deal with harsh shifting, it appears by using the correct inputs we can clear it so the transmission can reprogram (self teach) itself.

The file is 94 pages with lots of good information.