Help! At the end of my rope

DarylF

New member
Sep 17, 2022
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Anyone please help us! 03 Lb7. Built trans, lift pump, Triple disc, Dan's Tcm, reputable tune.
It has shifted horribly hard from 3-4 over 70% throttle since built, with only a shift tie code once. I'm talking tailgate flops down, about hops off the ground. The builder whom has built many Allison's, has pulled it twice, second time new core, new valve body, new Dan's Tcm ( twice ) and new tune. Still shifted horribly over 70%. Found low rail pressures so new CP3. Still shifts bad over 70% throttle. Changed mafs, throttle pedal, ignition switch, speed sensors on trans, new tone ring and output sensor on tcase, shifter cable and nsbu switch. Checked harness and fuse box, nothing. EFI Live can't see anything wrong. No codes except a shift tie once in tune 5 at full throttle that led to a third gear limp.
I'm at my end with this truck. Please help, I'm begging here.
 

juddski88

Freedom Diesel
Jul 1, 2008
4,500
46
48
Chesterfield, Mass.
Unfortunately, you'll likely have to bring it to a more capable tech to sort this out. Some other info we would need to try to help guide you from here, remotely, is: What parts are in the trans? (Any and all aftermarket parts/mods); Are you able to upload a few .log files here to show us that "efi live can't see anything wrong?"
 

2004LB7

Well-known member
Dec 15, 2010
4,237
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Norcal
put the stock tune back in and see if the transmission still does it after relearning. If it still has trouble, keep it stock until you sort out the issue. if it shifts fine but returns once you upload the new tune then you know it's the tuning
 
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DarylF

New member
Sep 17, 2022
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put the stock tune back in and see if the transmission still does it after relearning. If it still has trouble, keep it stock until you sort out the issue. if it shifts fine but returns once you upload the new tune then you know it's the tuning
The stock tune was put back into it, and it did it.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,069
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Neenah, Wisconsin
WTF are "stacked shift kits" and "Lock up mod"?
Guessing RatioTek & TransgoJr (hopefully, doing a full Transgo in a 5spd usually ends up in killing clutches at added power/more aggressive disks), I learned that one from Mike and from my own trans failure before I started actually building them.


Southern Wisconsin.
How far are you from Appleton/Oshkosh? I can help you out there with some logging/diag (I build Allisons).
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
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Texas!!!
Sounds like it has a full transgo kit with the C2 mod and probably too many fictions in the C2 clutch. Your best bet would be to have a stock drum installed without the C2 mods from the transgo kit and make sure they only use 7 frictions with stock steels.
 
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DarylF

New member
Sep 17, 2022
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1
I appreciate all the responses. The builder keeps claiming it's the truck. I had another reputable shop look at the truck they weren't sure.
 
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DarylF

New member
Sep 17, 2022
9
0
1
Guessing RatioTek & TransgoJr (hopefully, doing a full Transgo in a 5spd usually ends up in killing clutches at added power/more aggressive disks), I learned that one from Mike and from my own trans failure before I started actually building them.



How far are you from Appleton/Oshkosh? I can help you out there with some logging/diag (I build Allisons).
I'm near Madison.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,069
376
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Neenah, Wisconsin
I appreciate all the responses. The builder keeps claiming it's the truck. I had another reputable shop look at the truck, they are confident it's the trans.
Sure sounds like it's the trans. Who built it?


I'm near Madison.
Well if you're in this neck of the woods I'd be happy to take a drive in it and take a log to see what's going on. I believe @JoshH hit the nail on the head personally, and there is a builder in that area who's been known to use the full TransGo kit but he's no longer in business (Cole at BBP).
 

Ne-max

I like turtles
Nov 15, 2011
3,360
60
48
Lincoln, Ne
Is the TCM a stock file? If not get a stock TCM tune in it. I will not build a trans without knowing who's TCM file is in it. Even at that I prefer stock on 95% of the builds.

If it's the stock file we need to know what c2s and C3s.

If you can't answer those questions I'd take the truck to Brad.