potential converter issue??

so, from the initial tune till now, 2500mi after my t4 install, the trans has shifted from 5th locked into 6th locked then instantly kicks the converter out at like 45-50 mph, way under the turbo... until it locks up again at like 65. all other gears and shifts are cool. tuner says it should be ulocking between gears..

if a solution isn't found via the tune (there was no issue before on the stock turbo and extreme street tune)

what could be possibly keeping the converter locked????

The tune is what controls lockup. This sounds like a mismatch between the 5th and 6th gear lockup functions.

What tunes?
Only under lite throttle?
Did you revise your tune for the non-vgt?

I have had a couple people recently with a "similar" issue that when they switch to a non-vgt the 5th to 6th gear just does not "work right". There are multiple ways to get the non-vgt more driveable... but if not fixed correctly then the turbo/truck will hate life when you shift into OD.


Long story short... sounds like tuning to me.

KCTurbos said:

What tunes?
Only under lite throttle?
Did you revise your tune for the non-vgt?

I have had a couple people recently with a "similar" issue that when they switch to a non-vgt the 5th to 6th gear just does not "work right". There are multiple ways to get the non-vgt more driveable... but if not fixed correctly then the turbo/truck will hate life when you shift into OD.


Long story short... sounds like tuning to me.

Click to expand...

without trying to sound like I'm calling anyone out, cause I'm not, (I'm happy with the tune overall its just the slamming into 6th just to unlock instantly that's bugging me) its idp's ex street tune

and yea light throttle. like 15-20% just enough to cruise.

shifts into 5th great, locksup in 5th perfect at low throttle cruising, just shifting from 5th locked it stays locked shifting hard into 6th then its like it realizes its way under the turbo and unlocks the converter. like a split second after getting into 6th.

slightly heavier load, say 25-30% throttle and up, it wont lock in any gear and stays ontop of the charger then locks the converter in 6th at like 65. and is golden.

You have described what happens when the 5th lock and 6th unlock curves don't match. I've done this when I was developing transmission calibrations, but I fixed it before anyone else drove it.