Allison 6sp: Need trans Help!!Built allison issue

LMM_Austin

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Oct 31, 2015
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New York
hey guys i have an 08 d-max putting out 650hp to the wheels. Now onto the issue trans is built did it myself and now having some issues, tranny is tuned by ATP (Idaho rob). Tranny has suncoast g-max kit with Mike L trim springs, mike l shift valve springs, and mike l pressure spring for the pump, has transgo Jr shift kit, transgo A1 shift valves, and goerend billet converter. Ive been driving it for the past 10,000 miles tranny was shifting good for a while but always noticed the shifts from 1 to 2 and 5 to 6 were not crisp like the others i believe the correct term would be flaring. I ended up pulling the valve body down a few times to check all my valves to make sure they moved free found the my trim valve b had slight resistance. clean bore just enough so it slid freely got it altogether and through a relearn not as bad as it was but still has the issue. Also ive had the trans go into limp mode 3 times in the past 10,000 miles and its always out of the clear blue when i dont have my tech2. Ive called everywhere for help and no one seems to have any advise im starting to pull my hair out. Any help would be great.
 

Mike L.

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Aug 12, 2006
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Problem is we don't know how or what you did inside the trans. There are no codes for screw ups.
I have said this many times; Allisons are easy till they don't work. Now go earn your money.:D
 

Jakemax04

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Jun 28, 2013
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Could be a c4 piston problem, 2nd gear and 6th gear both use the c4 clutch. It's a possibility anyway.
 

LMM_Austin

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Oct 31, 2015
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New York
All the clearances were spot on went putting it together. And I did call suncoast and they pretty much told me I'm on my own. Guess I'll pull it back down any recommendations to look fo?
 

PACougar

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Jun 27, 2012
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Just be thorough when you take it apart and check everything on the way down. I'd send the VB to Suncoast to be tested. Right now you're at the point where the only person that can really help is whoever tears it apart.
 

Mike L.

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I'm honestly not to sure what the pressure is

Did you check it? How did you check it? If we're going to help you, don't make BS statements. We need facts.
How many of these clutch replacements have you done? We won't call this a build unless you've done a couple hundred with success and know how everything works.
 

LMM_Austin

Member
Oct 31, 2015
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New York
I honestly don't know how to check it if you would like tell me I would appreciate it. This the first 1 I've ever done it's a learning curve for me that's why I'm coming to you guys for help as I am stuck
 

HeavyDuty204

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May 26, 2014
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Manitoba, CA
I don't want to derail the thread here, but can someone give me a brief description of what a flare shift would feel like / act like?

Total newb question.
 

Mike L.

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Aug 12, 2006
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I don't want to derail the thread here, but can someone give me a brief description of what a flare shift would feel like / act like?

Total newb question.

When you experience a flare ( slip ) during a shift, your engine rpm will rise and the transmission will feel like it's in neutral for a second or 2. It will feel disengaged.