How is everyone's 3-4 shift

[[email protected]]

I have a SCIII in my 5 speed truck with a 1056. With a 01 tcm it seemed the 3-4 shift was more smooth at WOT but it liked to flare the 3-4 shift at WOT. With my original 05 os I can watch the rpms on the log where it starts to drop rpm normaly to shift into 4th for about .4 seconds then in the next .1 second it drops from about 3200rpm to about 2500-2600rpm. This happens at WOT or near WOT.

You can definetly feel it in the shift and at the .1 second point of the shift the tcc slip goes negative.

Ive heard this is normal with the transgos and sc kits becuase of the extra capacity and pressure when the C2s come on?

I just hope its not revresing the driveline or really stressing any of the compontents.
Im going to try to command the tc to unlock on this shift to see if it will smooth it out to, but I don't think there is a way in efilive I can make the tc unlock for the 3-4 shift at wot without to completely not having it lock at all?

 

[8100 Power]

When my trans is cold, it shift's hard. But after warming up some it will smooth out for me.

 

[SmokeShow]

I would check your ECM tuning for most of the defueling situation. But yes, for some, the 3-4 shift is the more problematic shift. I can't remember the exact nuances of why but I think that might be when the most clutch packs are coming on and/or going off and it's just harder to get right.


Mike or others should be able to set you straight though.


C-ya

 

[770JOHNNYW]

Yea you can def tune that out with some time and patience mine flared on the 2-3 and 3-4 it just takes some testing

 

[TrentNell]

The setup on the c2's when the trans is built can be made to help this issue . the next bet is to work on the defuel . The c2's are engaging to quick , so fix it mechanically or add defuel to slow the shift .

If it is the TC locking your feeling, and it is hitting the same time as the shift , the only thing beside getting it to lock earlier ( lock up controller ) is to lock it later past the shift but it isnt going to be good for performance .

 

[Mike L.]

C2 ( 4th gear ) comes on with full main line pressure while C3 is being pullsed of and releasing under spring pressure. We install a Transgo shift kit with C2 piston mod to overkill the C2's, add extra clutches and add main line pressure to boot. We just caused the worlds biggest tie up on the 3/4 shift. Problem needs to be addressed internaly first then tuning afterwards if necessary.
I have been sharing info with Alto and there will be some changes made to help people fix the problem.

 

[paint94979]

C2 ( 4th gear ) comes on with full main line pressure while C3 is being pullsed of and releasing under spring pressure. We install a Transgo shift kit with C2 piston mod to overkill the C2's, add extra clutches and add main line pressure to boot. We just caused the worlds biggest tie up on the 3/4 shift. Problem needs to be addressed internaly first then tuning afterwards if necessary.
I have been sharing info with Alto and there will be some changes made to help people fix the problem.

Mike L. fixed my 3-4 hang

 

[LWATSON]

My 3-4 shift is firm when the tranny is cold. Also if the truck sits for an hour of so it does it on the first shift cycle through the gears, after that it smooths out more and more each time I go through the gears. At WOT it seems to shift fine, but I never go through the gears at WOT until my tranny is up to temp.

 

[S Phinney]

Are you tuning your tranny also?

 

[Mike L.]

Are you tuning your tranny also?

Tuning the Alli will not help at all with this problem. The problem was built in and not realy noticable till the mods started. We in the aftermarket made this bad. We cannot fix the lame computer so we try and fix the adverse results from our mods.

 

[THEFERMANATOR]

I know my 01 OS does this, but the 02 would adapt and would shift like butter on all of the upshifts. The downshifts was another story with the 02, whereas the 01 downshifts fine. If I could merge the 2 together I'd have a sweet shifting ALLISON, but it is definately driveable as is with the 01. Once I get some free time I'm gonna call MIKE L and see if I can try to comprehend some of his knowledge and maybe figure out my 02 OS problems so I can run it.

 

[duratothemax]

mine has a perfectly clean 3-4 shift at ALL throttle positions and all power levels.

 

[The Neens]

mine has a perfectly clean 3-4 shift at ALL throttle positions and all power levels.

Ahhhhhhhhhhh, is that why ur cronies scratch themselves:dontknow:

 

[whitetrash21]

:spit:.... The FB whore has been found....

 

[S Phinney]

Tuning the Alli will not help at all with this problem. The problem was built in and not realy noticable till the mods started. We in the aftermarket made this bad. We cannot fix the lame computer so we try and fix the adverse results from our mods.

I have to respectfully disagree with the statement of not helping. I have tuned several and have had very good results. My stage 5 shifts smooth and crisp without hesitations at all power levels. Tuning makes a very noticeable difference in drivibility and shift quality.

 

[Mike L.]

I have to respectfully disagree with the statement of not helping. I have tuned several and have had very good results. My stage 5 shifts smooth and crisp without hesitations at all power levels. Tuning makes a very noticeable difference in drivibility and shift quality.

Try your tuning with the full 8 clutches in C2 from the Alto power pack and pressure shim with modified converter flow valve that has no knock down.

 

[paint94979]

I have to respectfully disagree with the statement of not helping. I have tuned several and have had very good results. My stage 5 shifts smooth and crisp without hesitations at all power levels. Tuning makes a very noticeable difference in drivibility and shift quality.

LOL if it is a mechanical problem how can it be fixed with tuning? You can't tune out a cracked piston can you?

 

[[email protected]]

Thanks for the help everyone.

This makes sense to me that with the transgo we have added main line pressure and have added extra capacity to the C2.
But I have a SCII (which I thought did not raise main line?)
So the extra capacity of the C2 overides the realeasing of C3, so C2 has a lot more fiction now so you get a uneven release and apply.

When I look at the rpms on my logs I can see it start to gradually drop rpm on the 3-4 then after about half a second it drops 700-1000rpms in about a tenth of a second. I assume this is the extra fiction of the C2 applying.

If the 01os flared on the shift im guessing a flare is better than a tie up so I should probably stick with a 01os?

I know we shouldnt mess with shift timing but what if I increased shift timing at WOT on the 3-4? Im thinking this might make the problem worse as control main would be lowered to decrease the 3-4 time making the C2 overpower the C3 even more and make the shift tie up worse? So maybe the oppiste would be true?
I know this should be fixed mechanically but it seems like if SC kits have been around this long I should be okay with my 3-4 shift as long as a have a good defule for the 3-4.

 

[ripmf666]

Lol I wish my truck would even shift into gear sucks having one you can't even drive.

 

[[email protected]]

I put the 01os back on and the 3-4 shift seems a lot better. The rpm drop on the logs is a lot less steep too. It also shifts better at part throttle too. The 05os would shift faster than it needed to at low throttle.

The 01os also seems like it request a lot better defuel to where it times it better with the shift, instead of throwing you foward in the seat on a shift on the 05os.