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Topic: 6 spd Allison auto trans shifting issue when batteries very low?? (Read 436 times) previous topic - next topic

6 spd Allison auto trans shifting issue when batteries very low??

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
Will n Pam

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #1 –
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.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #2 –
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
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #3 –
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.

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #4 –
Will run down to 9 volts
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #5 –
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
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159
 

Re: 6 spd Allison auto trans shifting issue when batteries very low??

Reply #6 –
Quote from: Keith and Joyce –
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. .....

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.
40ft 1997 U320