4T40E Sluggish Shifts - Transmission Forum

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4T40E Sluggish Shifts
Monday, March 02, 2015 10:21 PM
My 03' cavy shifts sluggish during high rpms. It shifts firm till about half throttle.Mostly from 1st to 2nd. It only has 87,000 miles and has never been abused since an old woman had it. Could this be a pressure solenoid or maybe weak springs in the valve body? I've got an hp tuner pro suite on order and plan on adjusting the tranny from there but has anyone else experienced this? I really don't think the clutches are wore out. Any help would be greatly appreciated.

WHAT DO YOU MEAN I NEED TO TUNE MY CAR?

Re: 4T40E Sluggish Shifts
Monday, March 02, 2015 10:23 PM
Jeff Kazee wrote:

My 03' cavy shifts sluggish during high rpms. It shifts firm till about half throttle.Mostly from 1st to 2nd. It only has 87,000 miles and has never been abused since an old woman had it. Could this be a pressure solenoid or maybe weak springs in the valve body? I've got an hp tuner pro suite on order and plan on adjusting the tranny from there but has anyone else experienced this? I really don't think the clutches are wore out. Any help would be greatly appreciated.


WHAT DO YOU MEAN I NEED TO TUNE MY CAR?
Re: 4T40E Sluggish Shifts
Tuesday, March 03, 2015 3:59 AM
I would do a trans flush and filter change since it is on the older side.

You could un plug the IAT sensor to see if it shifts hard. If it doesn't you have other transmission issues. "I WOULD NOT ADVISE driving around with the IAT unplugged."





Re: 4T40E Sluggish Shifts
Tuesday, March 03, 2015 7:07 AM
Hey MD Enforcer, thanks for the idea, I will give that a shot. As I browse through this site I see that everyone here is knowledgeable and willing to help each other with their build ups and general upkeep of their j-bodies. I'm sure i'll have plenty of question during my upcoming build.

WHAT DO YOU MEAN I NEED TO TUNE MY CAR?
Re: 4T40E Sluggish Shifts
Monday, March 09, 2015 5:03 AM
What happened?
Did you test it?




Re: 4T40E Sluggish Shifts
Tuesday, March 17, 2015 10:23 AM
Yeah and it shifted hard. I took and bumped up the pressure and it shifts great. Bumping up the pressure didn't help the shudder on hard take offs though but it will do until I order a new one or switch over to stick shift. I have a donor car but still not sure of everything involved in the change. Thanks for your help

WHAT DO YOU MEAN I NEED TO TUNE MY CAR?
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