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Installed vette servo tonight

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Old 07-13-2007, 10:48 PM
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Default Installed vette servo tonight

Well guys and gals I installed the vette servo tonight took about 45 minutes or so. Anyways I like the part throttle shifts but the full throttle shifts fall on its face when it shifts still. All I have done is a predator program with full bolt ons on a 2003 gmc sierra ex cab 5.3 4x4. I was hoping for a fast nice shift. Do you think it is my program and that is why it shifts like crap. It's almost like it stops pulling for a second and then shifts and then goes again. Give me your thoughts. Thanks, Jared
Old 07-13-2007, 10:56 PM
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Technically, it DOES stop pulling during the shift. The PCM retards timing to reduce power during the shift so the transmission won't break. If you make it shift faster with hardware (shift kit, apply piston, etc.) you will actually feel the power loss even more even though it hasn't really changed.
Old 07-13-2007, 11:10 PM
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hitting your rev limiter...i bet its doing the same thing mine did
Old 07-13-2007, 11:21 PM
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I have adjusted the rev limiter twice and my shifts are at 5800 and my rev limiter at 6100. I don't see how it is hitting. Please I need some advice
Old 07-13-2007, 11:34 PM
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It's just torque management rearing its ugly face. Exactly what James described.
Old 07-13-2007, 11:53 PM
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Get rid of that TM. My tuned bone stock 4.8 cherps the tires from 1-2 and the tranny is bone stock.
Old 07-14-2007, 12:13 AM
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With the predator programmer you should be able to reduce torque management as well as turn off the abuse mode. Those two changes will help with that "dead spot" in the shifts.
Old 07-14-2007, 03:34 AM
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you could very well be noticing the TQ managment,you will notice that UNTIL you get a custom tune to reduce or get rid of it all.
Old 07-14-2007, 05:16 PM
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ya it's got to be cause I logged the timing and it is 33 at wot and right at the shift the timming goes down to 24. It's got to be torque management. My next question is how much in the quarter mile will i pick up with a custom tune over the predator with all of the torque management pulled out. Let me know
Old 07-14-2007, 05:37 PM
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Before you do this, you have to realize that a stock 4L60-E is not strong enough to survive full powered shifts. It will fail prematurely. If the thought of your truck becoming undrivable and requiring hundreds of dollars of transmission work at some surprise point in the not-so-distance future makes you nervous, then leave the torque management alone and think about how important saving .3 seconds in the quarter mile really is to you.


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