05 4T60-e delayed 1-2 shift after startup

[patgizz]

2005 rendezvous 2wd 3400, 102k miles.

most every day the first 1-2 shift is delayed in the morning. like it holds 1 to the redline no matter the throttle position until you back off then it hits 2 and you continue on your way. it will also do this after work some days. nothing ever slips. fluid is clean and red, and the fluid and filter were changed at 80k.

in a lame attempt at google, i came up with no similar issues, only people with slippage and no shifts at all.

do i need a FSM flowchart to diagnose this or can one of you guys point me in the right direction?

[pocket-rocket]

Shift solenoid stuck?

I'm not versed in auto transmissions, but what about the pistons in the valve body sticking? Wasn't that a problem with the old 4T's?

[robertisaar]

hmm.... perhaps i would start at seeing if the PCM is commanding it for some reason, then go from there. i would think it would set a DTC or two if it wasn't supposed to be happening.

[patgizz]

no CEL, no DTC's. scanned with hptuners. unfortunately 2005 u-platform is not compatible with much of their program.

[patgizz]

ok here is an update.

i never experienced this for myself as it is my wife's buick.

i drove it today and this is what happens:

it is always the first 1-2 shift after startup, but it does not happen every startup. sometimes it shifts flawlessly. but i got on it out of the driveway and instead of hitting 2nd it falls out of gear completely. you can rev the piss out of it, bounce it off the limiter, and it just finds 2nd when it feels good and ready. then afterward, every 1-2 shift is perfect.

sticky 1-2 shift valve? bad solenoid? any ideas? is the valve body under the side cover or in the pan? it's literally been 10 years since i've been inside one of these things to remember.

any assistance would be greatly appreciated. i'm thinking it must be a solenoid or in the valve body as if it were a clutch pack problem it would happen more than on the first shift after startup.

[carbon]

Just to be clear you are looking at a 4T65e... the 60e was discontinued in 99.

The valve body is most definitely located behind the side cover. I have a 2006 Saturn Relay U-van and the trans is unfortunately the only thing that seems to be fully right about it. So I can't be of much help, sorry.

Here's a guy with a Pontiac Montana U-van with what looks to be a similar problem to you...

http://www.youtube.com/watch?v=SdFok3WSIsQ

http://www.youtube.com/watch?v=uSVFX0Sbfyg

http://www.youtube.com/watch?v=rquiT92h73k

http://www.youtube.com/watch?v=en2ecgNOnVc

Obviously you have to get to it, you can see they dropped the driver side of the drive-train down and pulled the cover in the van.

[patgizz]

so basically it's a colossal pain in the sack to change a $40 part. sounds like typical FWD GM stuff, like when the alternator went bad on my DOHC lumina. i still have the 4 foot long 3/8 drive extension to get the rear support bolt from the driver's side wheelwell.

thanks for the links. the buick is excellent, just has that goofy 1-2 shift problem. it runs great, stops great, safely hauls my wife to work and our son around.

[robertisaar]

i still have the 4 foot long 3/8 drive extension to get the rear support bolt from the driver's side wheelwell.

of the 1,000 methods i've heard of to change the LQ1 alternator the fastest, this one is new to me.

[patgizz]

of the 1,000 methods i've heard of to change the LQ1 alternator the fastest, this one is new to me.

straight outta my 94 lumina FSM