Hi Forum :-) I am hoping someone can assist :-) 1995 Foretravel RV with 6 spd auto Allison trans cat engine... batteries very very low (changing them out) and trans wouldnt shift to R then not to D got batteries charged a bit and shifted to D then after two hour drive full charging batteries seemed ok... there was a beeping sound when the trans would not shift or stay in R or D... thoughts welcome thank you Will n Pam
When that is happening there is something wrong. I didn't know low batteries would do that. If the engine is reving to high and
maybe too low that will happen. If you have slides and they are out and if there is jacks and they are down both those things could
cause the trans not to go into gear. It depends on what the manufacture put in for safety.
Will,
To your basic question if your batteries are low/bad it will mess with the trans. ECM and cause the trans to do what you describe. You should be able to pull the trans. codes through the shift pad and you may get a 13/12 code for low voltage (IIRC). As a side note low voltage is bad for the ECM if it continues to have to try to function on low voltage.
Mike
Turn on Boost switch to bring house batteries into play. Why doesn't the engine alternator generate all the current you need to shift. Voltage when engine is running should be normal, not low. Coach does not run on battery bank. Battery bank is used to start engine.
Will run down to 9 volts
When batteries supply too lower voltage all sorts of weird things can happen. I would not worry about it if the new batteries cure the problem. Make sure the alternator is charging properly and the connections to the batteries and and grounds are clean. Problem will almost certainly go away. If coach has sat for a while something in the trans might be sticking. Take coach for a drive and it will probably free up.
Keith
X2. Would find if harder to believe if it had not happened to me. Car started throwing error codes for one of the exhaust sensors. First plan was to replace the sensor, but it was a bear to get at so did some additional research and found low voltage could trigger the same error code. Battery was 10 years old. Still turned it over and ran without issues, but apparently caused enough voltage variation to cause the error. Replaced battery and issue has not re-occurred. Like Keith said, also ensure connections and grounds are clean.