Suncoast not shifting good.

I put in a suncoast stage V with a 1056 converter and i have the same tunes i ran with my stock trans right now, the 3-4 shift is not smooth at all, it will slam and jerk into gear, sometimes it hangs for 2-3 secs then jerks and slams into gear and sometimes before it goes to shift it feels and sounds like im out of fuel(kinda like i keep letting off and on real fast), its not throwing any codes and i did the fast learn when it was installed over 4500 miles ago. Now my question, is it a tuning issue or is it mechanical inside the trans itself, all filters were changed today to be sure it wasnt a fuel filter. Its not a big tune im running yet(not over 500rwhp). I talked to the guy who built my trans at suncoast and he suggested changing the filter and checking the rail pressure then the desired pressure, its all good. It will be going back on warranty if i cant get it figured out, im hoping thats my last resort seeing as how im from canada and it takes 2-3 weeks to get the trans down and 2-3 back up :bad: any help or suggestions is appreciated.

Who's tuning are you running? I would first start with a proven tune that you know works well on all trucks. Second, how many miles are on this new trans? You need to give it a few 100 miles for it to shift ok. It took mine about a week.

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Originally Posted by 8100 Power

Who's tuning are you running? I would first start with a proven tune that you know works well on all trucks. Second, how many miles are on this new trans? You need to give it a few 100 miles for it to shift ok. It took mine about a week.

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Ted @ MPLmotorsports.com did my tuning, it shifted fine with my stock transmission. Roughly 4600 miles. What do you mean give it a few 100 miles for it to shift ok, do you mean like hard on the throttle for it to learn? Also, it shifts perfect untill you go over 40% throttle.

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Originally Posted by 03dmax90

Ted @ MPLmotorsports.com did my tuning, it shifted fine with my stock transmission. Roughly 4600 miles. What do you mean give it a few 100 miles for it to shift ok, do you mean like hard on the throttle for it to learn? Also, it shifts perfect untill you go over 40% throttle.

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Shifting it through all the gears continuously at variable throttles will help the Allison adapt better. Honestly, what help mine the most was to flash in a TCM Tune and check the "Clear TAPS" button.

On Edit:

You should have cleared up shifting by now...

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Originally Posted by 8100 Power

Shifting it through all the gears continuously at variable throttles will help the Allison adapt better. Honestly, what help mine the most was to flash in a TCM Tune and check the "Clear TAPS" button.

On Edit:

You should have cleared up shifting by now...

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Taps were cleared. Twice. :doh2:

Anyone??

It is probably the way the tune is written

Have you tried a stock ECM and TCM tune yet? Many times this is what you need to do to rule out tuning or mechanical issues. The TLIQ table plays a HUGE role in how the trans will shift, espescially at upper RPM's.

Ted built my SCIII so he knows those kits. I am pretty sure he has a fair idea of what he is doing with the tuning. Why not get him to tear your tranny down instead of sending back to suncoast?

I am having a similar issue. Did you ever figure out what was wrong?