2-1 hard downshift

LB7Diesel

Oh Boy!
Sep 3, 2006
1,355
0
0
Melbourne, F.L.
My trans has had a hard 2-1 downshift for awile now. It only does it once in the morning when cold. It won't do it anymore until the next mornings first 2-1 downshift. Any thoughts?
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
26
38
64
Norco CA
www.mcratracing.com
There is a set of taps that is just for downshifting. When I would run a Kodiak TCM it would knock your teeth out at first.

We need to figure out what to adjust.

Make sure your TCM tune DOES NOT have adaptive downshifting DISABLED.
 

MACKIN

Smell My Finger...
Aug 14, 2006
3,948
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Connecticut
Weird it goes away after you get some heat into the tranny. Is it when you apply the brakes? I ask becomes sometimes mine has some quirky downshifts when braking.

But I'll get a buzzing in the peddle like the ABS is kicking in.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
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Fullerton CA
My truck does it also. I would imagine that it has something to do with the apply and release of the larger clutch stacks, different friction coefficient, and thicker fluid when cold. I think the changes that have been made in a built Alli falls out of the adapt strategy parameter.
 

LB7Diesel

Oh Boy!
Sep 3, 2006
1,355
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Melbourne, F.L.
Great feedback and info guy's, Thanks:hug:
As long as Kevin and Mike's truck do it, I'm ok with it:D
I'm not so sure it's heat that keeps it from continuing to do this.B/c I can go 100ft stop and it'll downshift hard, go another 100ft and it won't do it anymore:confused: Maybe it's from sitting all night and things sticking a little.
 

Philtopgun

Nice n Easy
May 5, 2007
710
0
0
45
Edmond,OK-still a Texan
Crazy, very cold here the other night about 29 degrees and mine did it from 2 down to 1. It has never done that before... I warmed the truck up and got up to second gear before the first stop sign. I slowed down and it hit 1st hard. Has not done it since....
 

LBZ4Me

New member
Jan 19, 2007
3
0
0
Mine was doing the same thing, and seemed to do it mostly while in Tow/Haul mode while braking hard. Like an ass it was one of the things I complained about to the dealer when my warrantee was about to expire, thinking I wanted to get it on record that there were tranny issues, in case it blew up for some reason :). Well after I picked it up they told me there was a reflash for the computer. (didn't say if it was a trans or engine flash). I was pissed, I really didn't want them messing with my tune (was back to stock at the time) but was nothing I could do at that point. Now that I'm done bitchin the trans has never hard downshifted since, and it was doing it daily when I took it in. Maybe those knuckleheads actually have a fix????
 

stroke250

I May Be Lost...
Jul 1, 2008
490
18
18
Idaho
mine does this also. seems to do it when cold and you can feel the abs kick in too. doesn't seem to do it with tow haul on. upshifts and downshifts fine otherwise.
 
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Cougar281

Well-known member
Sep 11, 2006
1,808
251
83
St Louis, MO
Mine was doing this until I broke it; since I rebuilt it, I haven't had that funky 2-1. Mine did all the stuff described above; goes away when warmed up a little, ABS kicks in... :dontknow:
 

stroke250

I May Be Lost...
Jul 1, 2008
490
18
18
Idaho
from what mike l said(please correct me if i am wrong mike), it seems some just do it and others don't.
 
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