question...4.2 envoy trans/diff slipping?

[ConeKilrAutoX]

I had a question to see if anyone else has had weird shifts in the 2004 4.2's ? It used to be ok. lately its been like a "double clutch" shift? I am not sure how to explain it... like if im going 30 and I get on it pretty good (not towing or anything) it starts to go for a second, quickly hesitates/bucks and then continues to go. usually only when you get on it heavy especially on highway. The temps have been very cold lately and i have a trans cooler but after 35 min of driving I would think it would be warmed up?

what do you think?

thanks!

 

[djthumper]

you connected up to read the temp? How many miles do you have? Have you changed the fluids? How long has this been happening?

 

[ConeKilrAutoX]

you connected up to read the temp? How many miles do you have? Have you changed the fluids? How long has this been happening?

trans temp (i have an inline temp sender and display) is around ~165. its also 20 degrees outside. I have north of 135XXX and trans fluid was changed when i put the cooler in during the fall. Differential was done about a year ago...you think i should do that again? I have driven it hard at the track last summer but "hiccups" just started yesterday. i remember it happened once before and i reset pcm and it went away so maybe thats all i need to do? could it learn to shift like that?

 

[fishsticks]

What gear? Sounds like you have a slipping clutch. I bet it's 2nd huh?

That hesitation is the clutch/band trying to grab.

 

[ConeKilrAutoX]

What gear? Sounds like you have a slipping clutch. I bet it's 2nd huh?

That hesitation is the clutch/band trying to grab.

yessir, however normal driving is ok though... only notice it when i hit down hard and on highway it does the same.

im sure it probably dosent matter what gear as much then right if it is the clutch?

 

[Wooluf1952]

yessir, however normal driving is ok though... only notice it when i hit down hard and on highway it does the same.

im sure it probably dosent matter what gear as much then right if it is the clutch?

No. You're thinking about a standard transmission.

Automatics have more than one clutch plate.

 

[fishsticks]

I would pull and replace the filter NOW. If the filter is clogged and causing a line pressure drop, you may get lucky and extend the life of your trans a bit.

Start saving for a rebuild now though.

 

[fadyasha]

Yeh I've had the same issue on my truck since 60000 kilometers ago and still running strong. Change my fluid and filter when needed. That being said surprisingly after the PCM tune this went away. A member from the old OS had mentioned that but never really took it seriously. Maybe it's a coincidence.

 

[ConeKilrAutoX]

Yeh I've had the same issue on my truck since 60000 kilometers ago and still running strong. Change my fluid and filter when needed. That being said surprisingly after the PCM tune this went away. A member from the old OS had mentioned that but never really took it seriously. Maybe it's a coincidence.

hmmmm??? maybe?? I plan on getting a pcm4less tune in the spring so we shall see!!!


and will do fishsticks

 

[fadyasha]

Maybeee u never know. I also had the gear level 2 tune on the PCM, think that's why feel the difference