Allison keep alive memory..

[Xengineguy]

I was wondering if anyone has verified 12 volts to the keep alive memory..
From what I have read it looks to be pins 10 and 70. Or wires 110 & 170. Pink wires?
I haven’t checked my truck yet. Might explain the harsh shifts on start up?

 

[Ronmar]

On the A0 they feed 12v via the VIM to supply the battery voltage to the TCM. I believe that comes from CB22. They supply 24v ign to the TCM via CB79. I will have to look at a diagram this evening to be sure about wire numbers.

They feed 24v battery and ign to the TCM on the A1...

What truck do you have?

 

[Xengineguy]

On the A0 they feed 12v via the VIM to supply the battery voltage to the TCM. I believe that comes from CB22. They supply 24v ign to the TCM via CB79. I will have to look at a diagram this evening to be sure about wire numbers.

They feed 24v battery and ign to the TCM on the A1...

What truck do you have?

It’s a 2001 A1. M1078

 

[Ronmar]

It’s a 2001 A1. M1078

Then yours should be 24V. I can look at the diag in a few hours to confirm wiring...

 

[Ronmar]

On the A1 24v battery is p115 pins 15 and 16. The wire numbers are both 136. it comes from CB43. And you pretty much have to have it available and the Allison TCU uses battery power as the source for its + output control signals like the one used to power the Neutral start relay K26. If it wasnt being powered you couldn't start the truck.

I think the Allison uses a non volatile memory, as on the A1, which typically has a manual battery disconnect switch, it would be routine to loose this power when that sw is turned off…

Are you indicating any fault codes on the transmission?

 

[Xengineguy]

On the A1 24v battery is p115 pins 15 and 16. The wire numbers are both 136. it comes from CB43. And you pretty much have to have it available and the Allison TCU uses battery power as the source for its + output control signals like the one used to power the Neutral start relay K26. If it wasnt being powered you couldn't start the truck.

I think the Allison uses a non volatile memory, as on the A1, which typically has a manual battery disconnect switch, it would be routine to loose this power when that sw is turned off…

Are you indicating any fault codes on the transmission?

No transmission problems at all, no codes. I had a friend that worked at Allison many years ago and had described the first
learning transmissions. He said when they were new the transmissions would shift very hard until they learned how you drive and
the load on the transmission.
I have a motorhome with a Eaton 13 speed auto shift. At first I hated the transmission, ( I was using the battery disconnect every
time I shut down). Now I never use the disconnect, and it shifts nice.

I will check mine when I get some time, thank you for your help.

 

[Ronmar]

If you are running 15W40? Is it cold there? I could see it shifting a little rougher when cold.

Have you forced the trans to relearn the shift points?

If this was an A0 I would suggest you check the trans throttle position sensor on top of the engine, as that can cause harsh shifting.

But since it is an A1, the TCM gets its TPS info from the same throttle sensor that controlls the engine via the data bus, and an issue there would probably cause other symptoms...

 

[Xengineguy]

If you are running 15W40? Is it cold there? I could see it shifting a little rougher when cold.

Have you forced the trans to relearn the shift points?

If this was an A0 I would suggest you check the trans throttle position sensor on top of the engine, as that can cause harsh shifting.

But since it is an A1, the TCM gets its TPS info from the same throttle sensor that controlls the engine via the data bus, and an issue there would probably cause other symptoms...

I’m running the oil that was in it, so probably 15/40 yes. Haven’t done a relearn yet. Temps here in the 30’s 40’s. I does sit inside
and it’s usually 60 or so. I only shifts hard on the first few shifts, then it’s better and better until you let it set for a few hours.
Not a problem but seems a little harsh if it’s just cold oil?? Thank you for your help

 

[Xengineguy]

Then yours should be 24V. I can look at the diag in a few hours to confirm wiring...

You are correct, I verified 24 volts on two pins of the gray connector. constant 24v