I have an 01 Thomas with an Allison MD3060 that is having issues. While on a route, the bus locked into 3rd and set the Check Trans light. It wouldn't shift into any other gears, not even neutral. Got it back to the shop and shut it off. Upon restart, light is off and it shifts fine. Went to test drive and it locked in 1st before I could hit the road. I pulled 2 codes: 2215-Turbine Speed Sensor and 5644-4th Range Verification Test. Are these codes related or do I have separate issues? Is it typically just a bad sensor that needs to be replaced?(I have one coming just in case) Is there some way I can verify without dropping the trans pan and valve body? I went and drove it today and haven't had any issues, I will drive it again later today to see if it changes with temperature.
Inspect the wiring to the sensor. You should peel the loom back about 2 feet and make sure none of the wiring is frayed or chafed when you install the new sensor. Many times this is all that it has been in my case.
Take a look at my recent post "Allison 3000 issue". I had the same problem with the same Trans and I found a bad turbine speed sensor that would go open once the oil reached 140*. get a gasket set P/N 29544784D "you will only use one gasket and a couple round brown seals out of the kit" and a turbine speed sensor P/N 29543433D and drop the valve body and the sensor sits right on top. Its much easier than I thought it would be, just time consuming. But as RonF states check all of your wiring for chaffing first.
Allison MD3060 Issue
Posted - 04/10/2017 : 11:36:50 AM
