Did you check to make sure the pin didn't fall out the solenoid plug? If you member that was my problem hahaha
Allison 6sp: One Unique Range Shift Inhibited Problem
- Thread starter nevelcol000
- Start date
I have a few more updates to this thread.
I have a tcm I use for pulling. It starts in 4th geard in d, 3rd gear in 3rd, 2nd in 2 and 1st.
I tried it out in the truck and it did not help.
So I started to think about hooking my schafer shifter up. I have never done this on an allison and actually think it may be a bad idea. I was planning on hooking it into the red (transmission side connector, and leaving the white connector for communication plugged in.
So I started by unplugging the red connector and starting the truck. I then selected drive and was in mechanical default 4th gear.
I selected trans data on the tech 2 and had a helper plug the red connector back in to the tcm. The firstg time it breifly showed c on d off and e on on the tfp switch indicating 4th gear. And then it went back to the all on default, (except r of coarse).
The tcm never turns any of the c d or e shift solenoids off except after I tried the red connector unplug trick again.
The second time I got 9 codes, p0711 tft, p0743 tcc sol, p0748 pressure sol, p0763 sol c, p0768 sol d, p0773 sol e, p0778 sol b, p0080 tcm power input, and p2810 undescribed.
These are basically the codes that correlate to the stuff in the trans attached to the red connector, pretty logical they would set.
However it did go into 3rd gear limp mode due to these codes!!
At which point tech 2 data for 3rd gear was normal on tfp and solenoid apply, as well as nsbu.
Upon key off/on cycle the codes all said passed this cycle and the trans was no longer in limp, it was back to a nuetral range inhibited condition.
So my theory now is that the transmission, wiring and tcm is fully functional. However the tcm is seeing something internally that it does not like but it is not setting a code.
Are there any can bus messages that the ecm may decide to send that inhibit range other than high idle or pto??
I have a tcm I use for pulling. It starts in 4th geard in d, 3rd gear in 3rd, 2nd in 2 and 1st.
I tried it out in the truck and it did not help.
So I started to think about hooking my schafer shifter up. I have never done this on an allison and actually think it may be a bad idea. I was planning on hooking it into the red (transmission side connector, and leaving the white connector for communication plugged in.
So I started by unplugging the red connector and starting the truck. I then selected drive and was in mechanical default 4th gear.
I selected trans data on the tech 2 and had a helper plug the red connector back in to the tcm. The firstg time it breifly showed c on d off and e on on the tfp switch indicating 4th gear. And then it went back to the all on default, (except r of coarse).
The tcm never turns any of the c d or e shift solenoids off except after I tried the red connector unplug trick again.
The second time I got 9 codes, p0711 tft, p0743 tcc sol, p0748 pressure sol, p0763 sol c, p0768 sol d, p0773 sol e, p0778 sol b, p0080 tcm power input, and p2810 undescribed.
These are basically the codes that correlate to the stuff in the trans attached to the red connector, pretty logical they would set.
However it did go into 3rd gear limp mode due to these codes!!
At which point tech 2 data for 3rd gear was normal on tfp and solenoid apply, as well as nsbu.
Upon key off/on cycle the codes all said passed this cycle and the trans was no longer in limp, it was back to a nuetral range inhibited condition.
So my theory now is that the transmission, wiring and tcm is fully functional. However the tcm is seeing something internally that it does not like but it is not setting a code.
Are there any can bus messages that the ecm may decide to send that inhibit range other than high idle or pto??
Yes Sir I pulled the pan down and checked checked the entire valve body. As far as I can tell I do not see any problem.
MAybe I can just ride shotgun with you at laplata! lol
Alright found and solved the problem.
Additional checks, check the vss, I unplugged the vss/oss and removed from tcase, then plugged it back in and let it hang, no change.
live plot of all speed sensors, no issue.
pid data showed the al5 would command gear 7 (reverse) or gear 1. It waited 3 seconds and when it did not get the correct drop in turbine speed it said wait I never shifted into gear.
So basically the software needs to see a drop in turbine speed to 0 once the trans is in gear.
This was a mechanical issue not electrical at all.
It was a stuck mechanical b trim not exhaust fluid properly.
And the solenoid only sticks if in the valve body not on the bench in a block test.
I hope this thread helps whoever has a problem.
Lots of good info here.
Additional checks, check the vss, I unplugged the vss/oss and removed from tcase, then plugged it back in and let it hang, no change.
live plot of all speed sensors, no issue.
pid data showed the al5 would command gear 7 (reverse) or gear 1. It waited 3 seconds and when it did not get the correct drop in turbine speed it said wait I never shifted into gear.
So basically the software needs to see a drop in turbine speed to 0 once the trans is in gear.
This was a mechanical issue not electrical at all.
It was a stuck mechanical b trim not exhaust fluid properly.
And the solenoid only sticks if in the valve body not on the bench in a block test.
I hope this thread helps whoever has a problem.
Lots of good info here.
Same Problem
Don't know if the weather has anything to do with it but I have seen where people have posted that this is happening in the cold.
2 nights ago I took my boat to the shop and on the way home I noticed that when taking off from a stop I had no power. I compared it to pulling my 35' TT. That is what it felt like when taking off RPMs really going up with very little takeoff. After about 7-8 take offs the check engine light came on. It stopped doing it and was fine all the way home (about 20 miles). Then the next morning I went to pick the boat up and after about 15 miles of driving I turned down a city street and accelerated to about 30 MPH when I heard and felt a bang. I thought my tailgate fell down. I came to a stop and after checking the truck and not seeing anything I got back in and when I put the truck in drive I got this message about shift inhibited. Put it in drive, M and reverse and would not move. I shut the truck off and set at the stop sign for about 10 mins, started it back up and ran fine. Ran all the way home, back to get the boat and towed the boat back home again. Probably about 60-75 miles since the "boom" with no issues.
My only worry is getting stranded right now. Any thoughts????
Don't know if the weather has anything to do with it but I have seen where people have posted that this is happening in the cold.
2 nights ago I took my boat to the shop and on the way home I noticed that when taking off from a stop I had no power. I compared it to pulling my 35' TT. That is what it felt like when taking off RPMs really going up with very little takeoff. After about 7-8 take offs the check engine light came on. It stopped doing it and was fine all the way home (about 20 miles). Then the next morning I went to pick the boat up and after about 15 miles of driving I turned down a city street and accelerated to about 30 MPH when I heard and felt a bang. I thought my tailgate fell down. I came to a stop and after checking the truck and not seeing anything I got back in and when I put the truck in drive I got this message about shift inhibited. Put it in drive, M and reverse and would not move. I shut the truck off and set at the stop sign for about 10 mins, started it back up and ran fine. Ran all the way home, back to get the boat and towed the boat back home again. Probably about 60-75 miles since the "boom" with no issues.
My only worry is getting stranded right now. Any thoughts????