Just had the same problem with my transmission last week (Allison 3066 with a retarder)..would not shift out of first gear. I had to replace the speed output speed sensor on the transmission. While I was at it, I also replaced the input speed sensor. About $350 for both parts and 30 minutes of MY time to replace them (VERY easy.) I was able to verify the problem with the touch panel codes. Also, when explaining my symptoms to my local Allison service center, the shop foreman told me the sensor was bad..even before I told him what code displayed.
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edited 07/04/12 08:29pm by swampman60 *