does anyone know how to fix the horrid 2-3 shift tranny clunk on a 2005 silverado? i read somewhere that the fix is in the PCM so i think HP tuners would be able to fix it.
does anyone know how to fix the horrid 2-3 shift tranny clunk on a 2005 silverado? i read somewhere that the fix is in the PCM so i think HP tuners would be able to fix it.
On one of your posts I read that the 1-2 is too firm, then the 2-3 is too firm, then it 3-4 is too firm. Your shift pressures and force motor tables are stock.
I see that the TCC lock up speeds are the same as for a 3.42 Silverado. I would put all the shift speed tables back to stock and just change the gear ratio, then hit the commit button. This will scale all the trans shift and TCC speed tables.
To soften the shifts reduce the shift pressures at the low torque side of the tables. Does the trans shift too harsh in tow/haul mode as well?
Russ Kemp
Russ, when i installed the 4.10 silverado tranny tune it fixed the shift firmness on all the shifts. Sorry for not clarifying. There is still the 3-4 shift clunk though.
anyone there?
I'm confused, 2-3 or 3-4 or both?Originally Posted by wreedz71
Mine clunks or "crunches" on light throttle 2-3. I'm sure
I have too much line pressure. But I haven't tried un-
messing-with-it. Seems like it would be a simple cut-
and-try deal to find something more comfortable in the
low pedal ranges; high pedal I think you want it all in.
If you have the latest GM cal (dealership or local tech2 owner) you should have the fix for the 2/3 upshift shift clunk.
Last edited by EC_Tune; 07-07-2006 at 04:51 PM.
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I think this is interesting, what is the difference? Or,
can someone provide a copy of this and the "clunker"
versions so Chris can check out the differences in his
spare time? Would be very nice to have access to
whatever it is, that matters.
2168 is the latest (New calibration to address customer complaint of second gear start, and reduce second to third up shift clunk.)
2168 m is the latest with a 4/3 downshift mod
2834 is the file that was replaced by 2168
Note: These are straight binary transmission files. They won't open in VCM Editor.
EC
Last edited by EC_Tune; 07-07-2006 at 04:53 PM.
Always Support Our Troops!
what can these be viewed in?
i took mine in a they reprogrammed the first couple of shift timing tables on the 2-3 shift. it helped a litte but did not eliminate it.
OH AND IT IS THE 2-3 shift!! Sorry for the wrong second post.
They can be viewed in a hex editor... But you would have to know your way around the calibration to begin with.
I don't think the HP Guys want us posting the roadmap to the calibrations anyway.
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My truck has the dreaded clunk too. But it is not the trans, i heard about the calibration changes that GM issued for the 05's, but in 06 they dont offer reprogramming, they just state it is "normal". I found the clunk is in the T-case. i layed under the truck and rotated the front drive shaft and then heard the clunk. I guess its normal, but i dont like it!
2000 Chevrolet ECSB Z71, 6.0, TVS1900 @15psi, Alky Control, BEI Blower Cam, 8rib, ARH 2'' LongTube Headers, Built 4L80E w Billet CK performance goodies, P I Triple disc . HPT 2Bar Tuned by T J @ BEI,
11.6 @114 @ 12 psi/no meth , new times to come , 630 rwhp second gear dyno with old 1-3/4 headers. This stuff is so much fun
so the 06 does it too???
they did not fix it, they "reduced it"
what year is your truck that is doing it? do you have a bin i could look at?My truck has the dreaded clunk too. But it is not the trans, i heard about the calibration changes that GM issued for the 05's, but in 06 they dont offer reprogramming, they just state it is "normal". I found the clunk is in the T-case. i layed under the truck and rotated the front drive shaft and then heard the clunk. I guess its normal, but i dont like it!
04 like in my sig bro. Sorry, i dont have the stock BIN. i currentley have a "locked" Nelson tune, but i am getting an unlocked tune from him so i can share info . Good Luck. i think your going to do like i do and live with it unfotunatley. From what i understand it is caused due to manufacturing tolerence differences.
2000 Chevrolet ECSB Z71, 6.0, TVS1900 @15psi, Alky Control, BEI Blower Cam, 8rib, ARH 2'' LongTube Headers, Built 4L80E w Billet CK performance goodies, P I Triple disc . HPT 2Bar Tuned by T J @ BEI,
11.6 @114 @ 12 psi/no meth , new times to come , 630 rwhp second gear dyno with old 1-3/4 headers. This stuff is so much fun
The 2-3 clunk has been around since that transmission was designed (700R4).
Its a mechanical slop issue between the two halves of the input shell during the release of the band and apply of the 3-4 clutch pack.
It wont hurt anything, and any calibration fixes just keep the clutches bound together longer to give the appearance of fixing it.
Personally I would just ignore it rather than beat up on the 3-4 clutch pack.....
-Ken
Guess I've been lucky. Out of the last 3 1500 series trucks I've owned (98, 99, 03) I've never experienced a 2-3 clunk shift.
I did cause myself to experience something similar to this when I had my line pressure set too high, but after fixing that it was fine.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
I'm guessing that buried in the code are some
apply / release phasing tables, that maybe aren't
too good at tracking changes to line pressure,
mods, converter, etc. These would be both a
neat thing to have, and a dandy way to go hurt
onesself. I know I have a clunkage on mine at
low pedal, the same place where people who've
picked up my trans tune fuss about hard shifting.
Probably a good place to start shaving back on
line pressure until either it goes away, or the
shift gets unacceptably soft.
How would you beat up on the 3-4 clutch? By trying to fix the clunk?
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