ALLISON TRANSMISSION INFOFLUID CHECK
This procedure will allow you to check your transmission fluid level from inside the vehicle, and it is also more accurate than checking via the dipstick.
To enter the transmission oil level display mode, press the UP and DOWN arrow buttons simultaneously on the mode selector.  A two-minute countdown begins when the following conditions are met:
The display should show *8 and then count down to 0.  Note that it will take two minutes to complete this countdown.  During the countdown, the display flashes and a count (8,7,6,5,4,3,2,1) occurs reducing by one digit every 15 seconds.
NOTE:Failure to meet any of the above conditions will stop the two minute countdown.  The shift selector will then display one of the following Oil Level Codes to show the reason for the countdown interruption.  The countdown will resume where it stopped once all conditions have been met.  Shift selectors with single digit display will display the codes one digit at a time.  Shift selectors with two digit displays will display the codes two digits at a time.
After the two minute countdown, the shift selector displays the oil level data as in the following examples:
To exit the oil level display mode, press the NEUTRAL button or simultaneously press the UP and DOWN arrows twice.
DISPLAYING DIAGNOSTIC CODES
2.If no codes are present, the display will show a dash (-) on a single digit display shift selector or a double dash (--) on a two digit display shift selector.  If codes are present, the code registered in the first of five code positions will display on the shift selector.  The code list position is the first item displayed, followed by the two digit main code and then the two digit sub code.  Each item is displayed for about one second.  The display cycles continuously until the next code list position is selected by pressing the MODE button.  The following list represents a code display using code 25 11 as an example:
3. To view the codes in the second, third, fourth and fifth positions (d 2, d 3, d 4, d 5), momentarily press the MODE button as explained above in step 2.  Momentarily pressing the MODE button when the fifth position is displayed, will restart the sequence by displaying code position one (d 1).
4. If a listed code is active, the LED indicator next to the MODE button will be illuminated on shift selectors with a single digit display.  On shift selectors with a two digit display, the MODE ON light will appear on the display.
CLEARING DIAGNOSTIC CODES
2. Drive the vehicle and check for code reoccurence.  If codes continue to reoccur, bring the vehicle to an authorized Allison Transmission repairing outlet to determine and repair problem causing the codes.
EXITING THE DIAGNOSTIC MODE
TRANSMISSION FLUID CHANGE PROCEDURES
If you can change oil on a car you can change the tranny filters on the D.  The kit consists of two filters, two sets of gaskets and three sets of rings.  There are two pair of round (looking of a cross section of the O ring)
O-rings and some square ones which are called square cuts.  Part number is Allison - Kit, Filter 29526899.  We have the short 2" pan.
Most of the oil does drain from the plug and you don't remove the pan (control module), instead, each filter has it's own cover which will leak some fluid when removed.
The filter kit comes with a diagram for changing the filters, albeit a small one.  Our transmission is a MD 3060.
Here are the step-by-step instructions:
On some D's. the buttons on the transmission shift light console are not backlighted.  Freightliner considers this a safety issue and will fix free of charge.  Call Freightliner (800-385-4357, have your VIN ready), and tell them of this problem (you may want to verify that they will fix this free, parts and labor).   Have them send a new wire harness, AND INSTRUCTIONS, to your nearest Freightliner service center and have them make the modification, which takes about an hour - if they know what they are doing!.  NOTE - This is covered under Freightliner Service Bulletin CSU 54-08.
TRANSMISSION SHIFTING PROBLEMS
Some members report that they are having extremely rough shift when shifting down from 2nd to 1st gear (as when coming to a stop sign).  Others report that, unexpectedly, their transmission shifts to neutral.  Reportedly, the problem is with some solenoids in the control box of the tranny.  (I believe this affects mostly pre-1999 D's, though not sure).
If your transmission goes into neutral by itself, the quickest way to reset it is to actually shut off the relay switch that is located in the upper vcr cabinet. This will make the tranny lose all of its driving memory and force it to reprogram and work properly again.  There is an Allison update, but I do not know what it is.  If you suspect that you are having problems, call Allison with your transmission serial number and see if your tranny qualifies for the solenoid changes.  Note - this is almost an all-day job!