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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: opus on November 20, 2010, 04:51:03 PM

Title: Servicing Allison 643
Post by: opus on November 20, 2010, 04:51:03 PM
I want to get this serviced.  Should I bring to an Allison dealer?  What exactly should be done regarding servicing it?
Title: Re: Servicing Allison 643
Post by: DMoedave on November 20, 2010, 08:01:45 PM
I dont have the 643 manual but have the 644/647 654cr manual and  when the oil is changed you drop the pan and replace the filter.  Some units have a remote filter. Some units also have a governor filter. (these were the early units i think). The oil should be examined at the change (maybe sent out for analaysis (i cant spell that one!) Inspection of linkage, shift speed adjustments,inspection of external lines and cooler. You can down load the info at www.allisontransmission.com (http://www.allisontransmission.com) If you have a clean concrete spot to do the work, most of it is the oil change and a good external inspection. Good luck
Title: Re: Servicing Allison 643
Post by: opus on November 20, 2010, 08:05:20 PM
I have the manual.  Didnt know if there should be more to it then fluid/filters.  I can do all that.  I dont wanting to be making adjustments and the such though....aside from the cable, which is fine.  I did however change the temp sending unit in the bottom of the pan.  Too cold and snowy to drain the filter so I did the one-two-three switch.  Spilled about 2 teaspoons of fluid.  Wow, I got lucky!
Title: Re: Servicing Allison 643
Post by: DMoedave on November 20, 2010, 08:12:13 PM
That has to fall under the aint broke dont fix it rule. They have precise shift points and adjustments, but if all is well...... cold and snowy!!!!! yikes i know its coming.