15 lml p0700 and p0732

Grss429

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Nov 4, 2020
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Just bought a 15.5 lml with 87k, first week i thought I had a cp4 failure, no fuel pressure and died while driving, turns out it was just the fuel filter [already replaced when i bought it]

Fast forward to now. Truck has a PPEI 120 def tune no trans tune and straight pipe.

Yesterday bought a set of rims and tires 20x10 with 37's it had 35s and then I had dead battery's do I spent 350 in 2 battery's. Get everything mounted and battery's in, go out and romp on it a little floor it from stop light and bam limp mode, first code p0700 checked Tcm codes and p0732 incorrect 2nd gear ratio. Cleared codes drove fine I haven't tried stomping on it as I was quite nervous.
Checked fluid its full and still had some pink tint to it. Doesn't smell burnt could use a drain and fill

Any ideas? Chevy tech seems to think it might be TCM failure. Or is there some tire size in the tuner I can change? Went from 35s to 37s

One other odd thing is when I tried to use my maximus 2.0 scanner and go into TCM Module it says not installed

Should I get a ppei transmission tune?
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Meaning? What? Are we talking trans problem? Tcm? It hasn't done it since that 1 time last night
could be trans, not likely tcm. you are running big power on a stock trans (no pressure mods from what we see) with big tires and to compound it, you changed batteries, upped the tire size again and smashed the throttle while it was most likely in a learn mode from changing batteries and tire size. If that trans limps from the code you posted, the trans is really hurting. LML' s like to pull power back unknowingly to you to save the trans as it sees it slip, when it does limp, its hurting bad.

based on what your telling us, you need to see a true allison build shop and have it properly diagnosed. no tune is going to save that trans.
 

Grss429

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Nov 4, 2020
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could be trans, not likely tcm. you are running big power on a stock trans (no pressure mods from what we see) with big tires and to compound it, you changed batteries, upped the tire size again and smashed the throttle while it was most likely in a learn mode from changing batteries and tire size. If that trans limps from the code you posted, the trans is really hurting. LML' s like to pull power back unknowingly to you to save the trans as it sees it slip, when it does limp, its hurting bad.

based on what your telling us, you need to see a true allison build shop and have it properly diagnosed. no tune is going to save that trans.
In my area there isn't really a Allison trans specialist, transmission shops are far and in between. The tune hasn't been on there long at all from the paperwork from previous customer, I just bought the truck, and don't beat on it, I've heard theses trans are staught and take abuse, would getting a trans tune to increase line pressure help? Like I said it hasn't done it since that one time, my scanner won't let me in the TCM module for some reason, I wanted to see if there was adoptive value reset
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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In my area there isn't really a Allison trans specialist, transmission shops are far and in between. The tune hasn't been on there long at all from the paperwork from previous customer, I just bought the truck, and don't beat on it, I've heard theses trans are staught and take abuse, would getting a trans tune to increase line pressure help? Like I said it hasn't done it since that one time, my scanner won't let me in the TCM module for some reason, I wanted to see if there was adoptive value reset
where'd you get this info? facebook? oh boy... no these transmissions are NOT tough, people that know nothing about them think they are because they dont understand how the trans trys to save its self as i explained. resetting TAPS will not fix this issue either, might make it worse. 120hp tune doesnt go into a truck and not see WOT. where are you located
 

Grss429

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Nov 4, 2020
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where'd you get this info? facebook? oh boy... no these transmissions are NOT tough, people that know nothing about them think they are because they dont understand how the trans trys to save its self as i explained. resetting TAPS will not fix this issue either, might make it worse. 120hp tune doesnt go into a truck and not see WOT. where are you located
North Carolina, wilmington, Jacksonville, Fayetteville area, the woman that traded it in was daily in it to Virginia, im sure its seen some WOT but its not running down the drag strip or pull 10k daily, I assume I can turn it down, according to the

Like I said it hasn't acted up but thst one time
 

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Grss429

New member
Nov 4, 2020
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Take it to tricounty transmission in castle Hayne. Donnie is really good with the Allison.
I might do that, just for a peace of mind I've put 450 miles on it and have been kinda rough on it and everything seems fine, smooth shifts, I think the whole new tires and dead battery's it learning was a little much for it. Right off the bat
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
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Gotcha, if you go, tell Chris, Shields crazy ass sent you there. Lol I'm going tomorrow bc my reg cabs 6l80 is pissed off about something...:ROFLMAO:
 

LBZ

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Trans build and a set of gears would do wonders for you!!
 

2004LB7

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Dec 15, 2010
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^^ 2x, some 4:30s will wake it up big time. May also be a little easier on it too by using gearing instead of grunt to get it moving
 

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