Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 7 of 7 Posts

·
Registered
envoy_slt
Joined
·
19 Posts
Discussion Starter · #1 ·
Hey Guys,

I am having a little issue with my 2004 GMC Envoy SLT. It has been acting up lately and i'm not exactly sure why but have lots of information to give up if it will help find an answer.

It has been having numerous issues related to what seems to be the transmission but has just started a new trend of shifting very hard out of 1st gear and almost feeling like it is darting forward. Second gear is much better but is still slightly funky. I wouldn't necessarily describe it as "slipping" but more like confusion on when it should be shifting or not shifting based on pressure added to the pedal. The car also seems to have lost quite a bit of its "get up and go".

A couple months back I replaced the thermostat which had been stuck open for a good 9 months or so before I got around to replacing it. After that, I have been only getting an intermittent CEL which reads P0014 Camshaft Position Timing - Over Advanced - Bank 1. I am not quite sure what that means but could see that it might be causing some confusion with the PCM on when to shift and not to shift. I was hoping that the PCM would normalize after some time of driving with a properly functioning thermostat but this didn't seem to happen. The CEL is currently off yet the shifting is still very aggressive. Lastly, it should be noted that I dropped the pan for the second time in a year and saw no signs of serious wear.

Do you guys have any idea what this shifting could be related to??
 

·
Registered
envoy_slt
Joined
·
19 Posts
Discussion Starter · #2 ·
Guys, no ideas?

Can anyone think of a couple things I could check out? I just don't want to have the tranny completely **** out on me and find out it could have been avoided so any help is greatly appreciated...
 

·
Registered
envoy_slt
Joined
·
19 Posts
Discussion Starter · #3 ·
reprogramming?

Why would a car all of a sudden need a pcmforless reprogramming? I can't tell if this solution makes sense for my issue or not. The tranny has been acting like this for a few months and hasn't seemed to get better or worse. Anyone?
 

·
Registered
2003 chevy trailblazer_ltz
Joined
·
2 Posts
I had a problem in my tranny in my 03 tb. I don't remember exactly what the problem was but it was causing the computer to up the line pressure causing a hard shift out of 1st. It was about a $300 repair.
 

·
Registered
2006 saab 9_7x
Joined
·
450 Posts
Don't know much about your tranny problems but if your thermostat was stuck open for 9 months, that may be the cause of the lack of get up and go. When the engine runs cold, the PCM dumps more gas into it to warm it up and that in turn plugs the catalytic converter and causes the loss of power. There used to be a commercial that said, Pay me now or pay me later.
 

·
Registered
2005 gmc envoy_sle
Joined
·
1 Posts
Posting in case someone else like myself is lurking for ideas...
Mine was doing all that, (05 Envoy) and what I eventually found out was the torque converter was slowly failing and the computer had compensated line pressure to hold in at higher speeds. that odd movement on the tack is not shifting, it's slipping (35 to 60 MPH) mine started to clunk once in a while after making a turn for a quick down shift w/ power back in and then eventually became what I felt was obvious slipping. Took me a year to get to the bottom of it and it took a FORD mechanic's reference of a GM Dealer with a qualified Tech to drive it with a scope/analyzer attached.
I replaced the tranny. 2300.00 to throw a Torque converter in it and a few seals and what not or 3300.00 for a new GM trans with a 100K mile warranty. I took the latter....obvious choice..
the first thing to do is reset the TCM. It'll shift much smoother but may slip more on slight uphills at 40ish or so. the harsh shifts will return if it's a failing TC.

And it should be noted that if all it is doing is shifting hard, you have no low temp codes (Will raise shift RPMs for faster warm up....) and have kept up on servicing the trans.........LEAVE IT ALONE...

Tony 05 Envoy. Same mileage as a suburban but easier to park.....
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
10 Posts
Same as TH. Mine started out like that and today am looking to drop it if someone can help with tips on how to separate it from the engine. I just need to crack it from the engine to drop it. Look up top 3 issues with the 4L60E on You Tube and you'll see this is one of the problems and a description. Mine started over a year ago and needed to update the Valve body but never got to it. The spring gets weak and the pressure builds up to compensate, hence the kickback. Mine has 210,000 miles so I think it was time anyway to drop and do a full inspection and replace all at once while its out.
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top