Ok Gearheads.. Transmission problems...

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Jan 2, 2009 | 02:10 PM

Storm

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Joined: Apr 2006

Posts: 3,294

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From: Neptune Beach, FL

Ok Gearheads.. Transmission problems...

So.. I'm thinking before I start pulling..

So far the following tunes cause transmission issues;

SDT - Ultra Comp
SDT - Aggressive Street
ID - Street
ID - Aggressive Street

In stock, there is no transmission issues.

What's happening.. Various tunes cause various problems..

Leave from a light, transmission goes to high gear, then back to low gear.
WOT instances where 3rd gets stuck, then shifts to fifth. Notice a loss of engine noise and an increase in turbo whistle.
Sometimes at 1/4-1/2 pressure gear shifts are sketchy, slippy, or rough.

What's been done, inspected

No codes thrown.
Transmission temp gets up to 170-175 quite frequently unless it's 40's outside.
No decrease in fuel pressure in any instance.
No lack of turbo boost in any instance, or drop thereof.
Transmission fluid smelled like crap (normal smell), nice cherry color, not burnt. Afterward electronics under pan look normal.
Oil pressure is good, oil is good.
Drive-train inspection was good. Slight knock in rear, probably needs a re-grease on the splines.
EGR checked, fine.
VGT DC Cycle appears fine.

So yes, I'm not sure what it is. I can't confirm mechanical, because the situation does not occur in stock programming. From my understanding, both tuning companies don't push line pressures that "high" to cause transmission failure in 55k miles. If this was the case, we'd have a whole lot of folks with transmission problems.

I started to push the theory with the lift and 35's, but all my calculations can't confirm a cause because the weight isn't that severe.

Any thoughts?