Allison 6sp: 2 to 1 downshift neutral

[TowU4Free]

mine will do it more often then none coming to a stoplight once you stop it bumps ya like a prius at 5mph a second or 2 after stopping, along with the sometimes neutral on the 2-1. were working on it currently to chase down any electrical gremlins that might be in there. Ill report back with more info on mine once i know. We did replace the Pressure Switch Manifold so far.

 

[Hnkstang50]

My lb7 used to do the delayed neutral shift almost every day when rolling through a stop sign or any time you didn't come to a complete stop. Hasn't done it once since my trans was built.

One time I had to stop hard to avoid hitting the car infront of me ( he stopped for a yellow light I was planning on getting through). About 5 seconds after I stopped I felt like I got rear ended. I actually put the truck in park and started to get out then realized there was nobody behind me. It must have been a delayed 2-1 shift from the hard stop. I can't remember if that was before or after the build tho.

 

[TowU4Free]

Yea, if it were once in a blue blue moon i could chalk it up to being "ok" but driving to work and you hit 6 stop lights 5 of which it bumps you actually start expecting it when you're driving anything and its annoying as heck!

 

[JDT4430]

My Stock tranny in my 09 with a transgo jr in it does this occasionally also. Seems like when it does it, it will do it a few times in a row then wont do it again for a while. Hopefully someone here can figure this out.

 

[Jesseh72]

Anyone solve this issue its getting old quick. I replaced the speed sensor in the transfer case and it still hit a false neutral. I am going to try a trans relearn on my insight and see if that helps but so far no luck.

 

[Mike L.]

Anyone solve this issue its getting old quick. I replaced the speed sensor in the transfer case and it still hit a false neutral. I am going to try a trans relearn on my insight and see if that helps but so far no luck.

Relearn will do nothing. Your insight won't do shit, never did.
There is no such thing as a false neutral.

 

[Jesseh72]

Good to know on the Insight i didn't think it would help but figured I would give it a shot. It is going into what feels like neutral between gears with a rpm spike that is what I was referring to as false neutral. Either way I am wondering if I should try a tcm reflash or used a tech 2 to relearn I am thinking this would be the next step in trying to diagnose this.

Thanks, Jesse

 

[RHallenbeck]

My 2010 LMM 2wd would do this ocassionally when not coming to a complete stop or slowing down for a speed bump in a parking lot... Stock tranny ..

Rick

 

[Mike L.]

Relearn does not stop slip. It diverges shifts and throws everything off temporarily for a while and might feel better. Your problem will come back shortly.
Relearn is ONLY used after a rebuild to clear the TCM memory from many bad shifts and limps. It is not a fix.

 

[Jesseh72]

Thanks for the clarification there Mike! Learning something every day with this thing lol. Just wanted to give you all a heads up I pulled the ABS Fuses after talking to a mechanic buddy so far I have not had an issue. I am hoping that a bad abs sensor in the wheel bearing is the culprit. Although it is weird because the wheel bearing felt tight when I checked them and I didn't have an ABS light. I will keep you all posted maybe this will solve your issues too.

 

[nsolimini]

Mike is correct, relearn will do nothing. I tried that and a few other things before I started this thread. That is interesting Jesseh72, let me know if you have any luck with the ABS sensors.

 

[WolfLMM]

What's odd is, mine has stopped doing this for the most part.

 

[Chevy1925]

just FYI, i was having this issue for quite some time. even talked to mike about it. since i fixed the ECM ground, put a fresh battery in and new starter, it has not happened since (knock on wood). i know low batterys can play havoc on the computers in these trucks and me running a single batt makes it more sensitive.

worth looking into for those of you having the issue.

 

[WVRigrat05]

What's odd is, mine has stopped doing this for the most part.

Yours stopped mine picked up where yours left off. I get that look when I go to take off an the truck revs finding first or decides to stay in second last minute, makes me look like an asshole.

 

[Jesseh72]

Mike is correct, relearn will do nothing. I tried that and a few other things before I started this thread. That is interesting Jesseh72, let me know if you have any luck with the ABS sensors.

Going strong still have had it hooked to a dump trailer and pulling an excavator has not skipped a beat. Worth the $40 for a new sensor. One of my sensors was real tight like it swelled in there when I went to clean them that was the culprit even with out an abs light.

 

[nwodiesel]

Just out of curiosity did you ever experience a "bump "when coming to a quick stop and it doesn't downshift to first until you are stopped ? I think these two things go hand-in-hand my best guess is some seat time and changing that internal filter like you did are the best bets but what do I know I'm just a keyboard warrior

Don't mean to kidnap the post, but Its funny Ive been experiencing the exact same symptoms as described here, especially the bump....almost as if someone tapped you from behind. I'm getting the "neutral" feeling too just as it shifts down from 2nd to 1st, and it almost neutral drops if you get on it too quick.Couple times it felt as if it was a standard, and the clutch isn't pushed in when coming to a stop. Today it got bad, which is why I'm on here btw. On my way to work, I stopped at the store and when I put it in reverse, it smashed into gear real hard and loud, and instantly the engine light lit up, It felt as tho it was in 2nd gear going backwards....and then when I put it in drive, it smashed into gear, and suckholed away....stuck in second gear.I limped it to work 4 blocks away and parked it. Came out just now and it is kinda normal, but the engine light is on. Now it feels funny taking off but does shift. I assume it went to limp mode. Not sure where to start. First trans issue. 01 LB7 stock, 285,000 KM's. Any help appreciated.

 

[nwodiesel]

That is interesting. I'm having all the exact symptoms, and now that you say that they kinda started acting up when I had a wheel sensor issue.... that I still have, but I ppulled the relay to stop it till I can get time to change both fr hubs complete. I thought that theory briefly, but didn't think that was possible either. Thanks

 

[Jesseh72]

Going strong still have had it hooked to a dump trailer and pulling an excavator has not skipped a beat. Worth the $40 for a new sensor. One of my sensors was real tight like it swelled in there when I went to clean them that was the culprit even with out an abs light.

Well it came back the abs sensor that I thought fixed it was short lived. I did have a 4x4 actuator go out on me but I do not think that was related. Sill searching for an answer I did find a little kink in the wiring to the trans but it all looks good when inspected.

 

[melms23]

Sold my lmm, but for what it's worth a couple times my 4x4 would activate by itself and be stuck til I shut the truck off. My truck also had the diff replaced in the first 10k miles and bolts came loose again even after that.

Probably not remotely related but I thought it was funny you should mention something with the 4x4.

 

[Jesseh72]

I am hoping this is the issue just stumbled on it. It was not leaking bad but that plug was filled up.