Ok guys, I have an enormous problem... I have an 06 Chevy Duramax, Allison 6 speed, little under 150k miles. about 2 weeks ago I was driving home, it was about 20 degrees out, roads were slightly wet. got home and i parked my truck in my heated shop (stays around 55 degrees constantly). Next day I started it up, let it run for a few minutes, and BACKED out of my shop into about 10 degree weather. I went to put it in drive and guess what pops up... Range Shift Inhibited. I am at my wits end. So far I have; change both internal and spin on filters, bored out the E valve, cleaned the valve body, replaced the NSBU/PRNDL switch (whatever you want to call it), replaced the internal wiring harness, and replaced the TCC solenoid all in that order. when i changed the spin on the magnet was full (Can't honestly say when it was last replaced but its been a long time). bored the E valve out because my buddy said it was a common problem. replaced the PRNDL switch because when hooked up to a Snap-On Solus Ultra, when selecting drive it would say i selected reverse (that did get fixed with the new sensor, all reads right now), and i replaced the TCC solenoid (or "F" solenoid) because it failed my 12v click test and did nothing when we tried to operate it with the Solus and when we did a running test it showed that it would build no pressure, no hum no click, nothing. If I unplug the internal wiring harness it will go into 4th i think and roll all day long. plug it in and it will roll a few feet and pop up range shift inhibited. the fluids are topped off. when i go into drive no matter how much throttle i give it, it wont react, no jolt or jerk, pretty much no sign that you would expect when you throttle up under normal driving conditions. There are no codes, current or past. the only thing i can think of is about 2 months ago i went up a hill while cruise was on (sidenote, EFI is installed i have always run it on 80hp for fuel economy) and it revved up, had about a half a second delay, then shifted and locked into 4th gear which i understand is limp mode? I pulled over, put it in park, shut it off, turned it back on, and all was fine, hasnt happened again since. Now this. I am at my wits end. the dealer tells me all my solenoids check out but tomorrow they are going to unplug somethings to test the clutches. after that the trans is getting dropped. From how it happened its gotta be something electrical right? i mean clutches dont go out sitting over night... please i need help bad, I've been out a truck for almost 3 weeks now. I know this is a lot to take in but i appreciate any help i can get
Allison 6sp: One Unique Range Shift Inhibited Problem
- Thread starter nevelcol000
- Start date
First of all this is way too long and doesn't tell us anything. We need codes. Just because yor red brick didn't show any does not mean there are no codes. When the Alli went into limp you should have codes. You should have read them. I can work with codes.
You cleared the codes. That's why there are no codes. Now you wait till it happens again and the read them and post.
ok it hasn't stopped happening. everytime i put it in any drive gear besides reverse the range shift inhibited message pops up. still no codes. the dealer has gotten the message everytime and everytime there are zero codes
Build the trans, and the truck and forget about it!
Tear it down and build or have it built better, and get efi live, you'll love it!
Sorry to hear about your issues, good luck!
Tear it down and build or have it built better, and get efi live, you'll love it!
Sorry to hear about your issues, good luck!
Building the trans wont fix the problem if there is an electrical issue coco...
So the dealer was able to duplicate the concern, yet they didn't point you in a direction? Or did you just tell them to check for codes and that's it?
So the dealer was able to duplicate the concern, yet they didn't point you in a direction? Or did you just tell them to check for codes and that's it?
yea they have no idea. everytime you start the truck up and put in any drive gear, range shift inhibited pops up. i told them to run every test possible to check all the trans electrical. according to them everything checks out. so i guess the next step is drop the trans but i still really think its an electrical issue... What could possibly be causing this but doesnt throw any codes?
Is it possible the tcm is bad? Mike L?
Know anybody 6 speed tcm to try and see if that is it? do it constantly do this or just once in awhile?
Know anybody 6 speed tcm to try and see if that is it? do it constantly do this or just once in awhile?
it constantly does this I have yet to do anything to make it stop even once. and i tried swappin tcm's. my cousin (thankfully) also has an 06 duramax. still did the same thing
I know that the Allison trans have an absolute ton of failsafes built into them, and even though all of them SHOULD throw codes when triggered, is it possible one of these didnt? like a bad ground or something?
Range shift inhibited happens in this case when the TCM does not see a rpm drop in engine rpm when it is shifted into drive. This will not set any codes. You will need to check all speed sensor readings. If all are ok pull the trans and inspect the C1 clutches, seals, and hydraulic circuit.
well i didnt drop the tranny but had some interesting results. started it up at the dealer and actually got it to go into limp mode. put in on the trailer, drove it 8 miles home. started it up, drove off the trailer and it was completely normal. shifted fine, drove it 20 miles, no problems. plugged it into the scanner at got p0700-00, p0722, and p003a-00 as MIL codes and: p0711, p0972, p0975, p0979, p0960, p0964, p2727, p2761, p0708, p0722, and p0878 as "failed since clear". but the truck runs normal fine now... any suggestions? Also, I am not for sure when the dealer cleared the codes, whether they did it at the end of the tests or did it only partway thru. they did unplug some things for the tests so I am leaning towards some of those FSC codes as dealer caused....
And yet again... started it up this morning, warmed up for 10 min or so, shifted to drive. range shift inhibited. now what?
Bumping an old thread here.
I am having the exact same issue.
Range shift inhibit after about 3 seconds of shifting to drive or reverse.
I have tried, nsbu, ignition switch, checked all powers and grounds, tried 4 different tcm's, checked the wiring from tcm through all solenoids, powers and grounds and checked solenoids and switches for shorts to ground power and each.
I can use the tech 2 to click all the solenoids, b trim only clicks once per ignition on.
The reverse pressure switch on tfp switches on when it is shifted to reverse but no reverse.
If I remove tcm completely, and leave unplugged I default to reverse and drive 4th gear. They hold all the power I want and it drives around all day like that. So mechanically c1,c2,c3 and c5 clutchs are ok.
line pressure is 150 at idle, 300 at 2200 rpm.
no codes ever are set, i do not have a pto signal inhibiting or a high idle.
the turbine speed and input speed are close and i have unplugged and tested them. I believe the range inhibit comes from the fact the tcm see turbine speed after it is shifted into gear.
The interesting thing is when shifted the tech 2 data does not show a solenoid command to switch from park/nuetral to drive. Its like the tcm is just not commanding it to change gears.
I hooked abnother valve body up external to the trans and held it against the case for ground. I then shifted from park to reverse and drive. the trans shifted to reverse and 4th of coarse and the solenoids c and e both got warm in my hand.
I am concerned about the b trim solenoid only clicking one time per ignition cycle.
This condition occurred after I changed the torque converter on this transmission. It is an 04 lly gtrim and the trans is built. We pulled the trans put a higher stall tc in and replaced internal and external filters.
The truck backed out of the shop and then drove forward about 50 feet and has not been right since.
If anyone has any ideas please help. I will post the answer once I figure it out to help anyone else having this problem.
I am having the exact same issue.
Range shift inhibit after about 3 seconds of shifting to drive or reverse.
I have tried, nsbu, ignition switch, checked all powers and grounds, tried 4 different tcm's, checked the wiring from tcm through all solenoids, powers and grounds and checked solenoids and switches for shorts to ground power and each.
I can use the tech 2 to click all the solenoids, b trim only clicks once per ignition on.
The reverse pressure switch on tfp switches on when it is shifted to reverse but no reverse.
If I remove tcm completely, and leave unplugged I default to reverse and drive 4th gear. They hold all the power I want and it drives around all day like that. So mechanically c1,c2,c3 and c5 clutchs are ok.
line pressure is 150 at idle, 300 at 2200 rpm.
no codes ever are set, i do not have a pto signal inhibiting or a high idle.
the turbine speed and input speed are close and i have unplugged and tested them. I believe the range inhibit comes from the fact the tcm see turbine speed after it is shifted into gear.
The interesting thing is when shifted the tech 2 data does not show a solenoid command to switch from park/nuetral to drive. Its like the tcm is just not commanding it to change gears.
I hooked abnother valve body up external to the trans and held it against the case for ground. I then shifted from park to reverse and drive. the trans shifted to reverse and 4th of coarse and the solenoids c and e both got warm in my hand.
I am concerned about the b trim solenoid only clicking one time per ignition cycle.
This condition occurred after I changed the torque converter on this transmission. It is an 04 lly gtrim and the trans is built. We pulled the trans put a higher stall tc in and replaced internal and external filters.
The truck backed out of the shop and then drove forward about 50 feet and has not been right since.
If anyone has any ideas please help. I will post the answer once I figure it out to help anyone else having this problem.