Lbz shifting hard HELP PLEASE!!!

Dirtymaxlbz9

New member
Feb 1, 2019
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Ok so I have a 2006 lbz with 145k on it and everything’s been great on it we’ll i bought it with 130k and I realized that as far as I could find out the trans fluid has never been changed so long story short I did a double drain and fill per what I read on here and couple weeks later noticed hard shifting mainly from 3-4. My tcm went out shortly after this and was replaced so it had to be relearned and still shifts hard so resetting taps won’t do it. I need help I used 7.4 quarts of transynd and it was really expensive I love my truck and don’t want to put thousands into it I need help pls someone give me ideas of what it could be. Also the tuner is set on stock. I changed the fluid to help my truck but I fear I may have dislodged some old junk and stopped up something. The shifts are just to hard to be normal and from 3-4 there is major defueling it feels like. Also I’m 18 and don’t have a lot of money but if I have to pay to have valve body cleaned out or solenoid changed will do anything $1000 or less and I’m game for I want my dream truck to shift right. Just don’t want to have messed up a perfect trans with a fluid change.
 

ChrisPerry

...........
Apr 4, 2016
209
6
18
Ventura, CA
When you did the fluid change, did you change the internal filter or the spin on filter? If so did you use genuine Allison filters?

Are there any codes being stored? Scan with a GOOD scanner as the cheapo ones don't always show the trans codes.

For example p0700 isn't a helpful code, but its the only one the cheapo scanner seem to show...

And welcome to DD :thumb:

:welcome3:
 

Dirtymaxlbz9

New member
Feb 1, 2019
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Only changed external filter and yes I used genuine Allison filter both times on the double drain and fill and when the tcm was replaced he said the only code was for a glow plug which I’m not worried about right now
 

Dirtymaxlbz9

New member
Feb 1, 2019
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Not chirping tired hard but the 3-4 shift you can always feel is extra firm like it kinda pushes your head forward when it shifts from 3-4 like it’s a long shift its hard to explain but that’s the best I can do. It’s definitely not right tho. I’ve drove plenty of duramaxs and that one shift is not right on mine. And I just have a superchips programmer set to the stock power level
 

Dirtymaxlbz9

New member
Feb 1, 2019
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And the throttle input doesn’t matter it still does it. I have noticed that anytime downhill it shifts smooth from 3-4. But sometimes for a while it just shifts hard in that one gear and then sometimes it’s not as bad but you can always tell something is wrong.
 

Dirtymaxlbz9

New member
Feb 1, 2019
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How’d do I remove it like it’s just one of the ones you plug in then unplug when your done so I just set it to stock and unplugged it a while ago but no matter stock or when I used to set it on tow it still did the same hard shift from 3-4
 

Dirtymaxlbz9

New member
Feb 1, 2019
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Will do I’ll let y’all know what is found when the pan gets dropped. If the filter was slightly clogged would that explain hard shifting in just the 3-4 shift?
 

torqued2dmax

Member
Mar 26, 2017
646
1
18
Brookville, PA
When you peel the filter apart (without washing it) , tell us know the type of material you find , aluminum , brass , dose any stick to a magnet are there alot of fibers like clutch material ? You might just luck out and just need a internal filter !
 

Dirtymaxlbz9

New member
Feb 1, 2019
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Just got results from local shop blown torque converter. Getting a billet one put tback in. Thanks for the help tho