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2003 gmc envoy_slt
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Discussion Starter · #1 ·
I was looking at finally getting a tune for my 03 envoy with about 150k miles on it. Now i really like the idea of really really firm shift firmness, but will increased shift firmness hurt out transmissions at all? I mean i have 150k miles on my tranny and i don't think the previous owner ever changed the tranny fluid. But i have also heard horror stories about changing your fluid after so long because the old fluid may have containaments that your tranny could use? Idk has anyone waited this long to do a tranny fluid change and be ok? I drive the car pretty hard, figuring i am only 19 :raspberry... and i am going down to school this upcoming semester and i want something thats gonna be reliable.

Thats my story... Any thoughts on what i should do? :undecided


EDIT:
Just looked at the site again and saw a nice little link that said:

Shift Firmness
Written by Alvin Anderson
Shift firmness - We ask people to describe what they want on a scale from 0-3. 0 means no changes. 1 is a slight improvement over stock. 2 is what we recommend to most people with daily drivers – it is a noticeable difference over stock, with faster, firmer shifts. 3 is for people who race a lot, it is a harsh shift feeling. We don’t recommend it unless you insist!

Unless you insist... sorta sounds like its not too good of an idea, like it almost might harm something?
 

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2003 gmc envoy_slt
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A faster firmer shift should be better for the trans, less slippage. It is not recommended because most people don't/won't like their head snapping. The 150k might be a factor.:m2:
 

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2003 gmc envoy_slt
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Discussion Starter · #3 ·
A faster firmer shift should be better for the trans, less slippage. It is not recommended because most people don't/won't like their head snapping. The 150k might be a factor.:m2:
150k might be a factor... hmmm would it be better if i changed my tranny fluid then did the pcm tune? is there any really high end tranny fluid thats going to be better? honestly i want a really firm shift... i dont like all the sloppy slippage :eek:
 

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2003 gmc envoy_slt
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8,149 Posts
Your best bet would be to call PCMforless and talk to them. You could also try a trans shop. Also the fluid should have been changed at 100k, so changing it now using a synthetic Dexron VI compatible fluid would be IMHO advisable. As you have noted, others recommend leaving the fluid alone.:m2:
 

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2003 chevy trailblazer_ls
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I would change the fluid to dex-VI, change the filter and clean the pan. See what you see in the pan and then go from there. So many people think that the tranny fluid is for life, then they wonder why it breaks down. Your ATF should have been changed at 50K. Let me guess, you also never changed the differental fluids or transfer case fluid, correct?
 

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gmc
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I was looking at finally getting a tune for my 03 envoy with about 150k miles on it. Now i really like the idea of really really firm shift firmness, but will increased shift firmness hurt out transmissions at all? I mean i have 150k miles on my tranny and i don't think the previous owner ever changed the tranny fluid. But i have also heard horror stories about changing your fluid after so long because the old fluid may have containaments that your tranny could use? Idk has anyone waited this long to do a tranny fluid change and be ok? I drive the car pretty hard, figuring i am only 19 :raspberry... and i am going down to school this upcoming semester and i want something thats gonna be reliable.

Thats my story... Any thoughts on what i should do? :undecided


EDIT:
Just looked at the site again and saw a nice little link that said:

Shift Firmness
Written by Alvin Anderson
Shift firmness - We ask people to describe what they want on a scale from 0-3. 0 means no changes. 1 is a slight improvement over stock. 2 is what we recommend to most people with daily drivers – it is a noticeable difference over stock, with faster, firmer shifts. 3 is for people who race a lot, it is a harsh shift feeling. We don’t recommend it unless you insist!

Unless you insist... sorta sounds like its not too good of an idea, like it almost might harm something?
First off I have rebuilt/modified several 4L60E.

Increasing the line pressure is one way to get faster shift but it does put more load on the pump. A better method is to install better servos and a shift kit and then tune the line pressure to suit. I use Trans-go shift kits and superior servos.
It does mean your going to stink of transmission fluid and unless you have the tools and know how this is job for a transmission shop.
The valve body has to come out to do it right. While your in there change the forward accumulator piston to an aluminum on - GM for some dumb ass reason likes to use plastic pistons and they tend to break then the line pressure drops causing a failure.

For parts I get them from here http://www.transmissioncenter.net/4l60e.htm

I've have very good service from these folks. If you run into a problem or need to ask a question they provide the answers.
 

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2003 gmc envoy_slt
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Discussion Starter · #7 ·
honestly, i dont know if any of them have been changed, i am the second owner of the envoy. I could try and give them a call, but even if i do, i should still change it since ive had it from 110k miles and its now hitting 155k miles.

About changing the internals, servos,... in the tranny, i wasnt planning on spending a bunch of money on it. I am thinking about just getting shift firmness 2. Still contemplating it though. its between 2 and 3. I will probably be doing the tranny fluid/dif fluid in about a week or two. So i will look at the pan and see what it looks like (any metal fragments or what not) I have a list going of things i want to do/fix before i leave for school. And money is hard to come by these days. But any more thoughts on anything are well appreciated! Thanks guys!
 

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Western Canada Chapter
2003
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6,421 Posts
honestly, i dont know if any of them have been changed, i am the second owner of the envoy. I could try and give them a call, but even if i do, i should still change it since ive had it from 110k miles and its now hitting 155k miles.

About changing the internals, servos,... in the tranny, i wasnt planning on spending a bunch of money on it. I am thinking about just getting shift firmness 2. Still contemplating it though. its between 2 and 3. I will probably be doing the tranny fluid/dif fluid in about a week or two. So i will look at the pan and see what it looks like (any metal fragments or what not) I have a list going of things i want to do/fix before i leave for school. And money is hard to come by these days. But any more thoughts on anything are well appreciated! Thanks guys!
In your case I would not go crazy. The theory still stands tall that "you have to pay to play." So if money is tight then be a little conservative and think about making it better but milder for the sake of your wallet.:thumbsup:
 

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2002 chevy trailblazer_lt
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11 Posts
First thing I would do is check the fluid is it burnt? If so sucks your in same boat as me I will drive it till it needs fixing. The go for the 2 on shift firmness. The 3 might be nice but I like the 2 for my daily driver. Agressive when I want to go but still not slamming my head back everytime. That what my 240 with an unsprung stage 5 iron disc clutch is for :D.
 

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2002 olds bravada
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118 Posts
I think that you are looking for info to help you decide on whether the pcm tune will impact the life of your trans. Someone already posted the snappier shifts come from less slippage which should be better for the trans. However, if you are looking for opinion on the feeling of level 2 or 3. I went with level 3 and it still shift easy when you are not accelerating hard. If you gun it the shifts are nice and firm not too harsh. I had read that many members were not satisfied with the level 2 and wished they asked for 3. I figured if I asked for 3, I probably would not want to send it back in for the tuning. I just dropped almost $300 to change all my fluids as my Bravie has just hit 100k. The trans was changed at 50k though. My suggestion is do a search for trans fluid changes and read the threads and try to make an informed decision. Many members will weigh on both sides of this one.
 

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2003 chevy trailblazer_ls
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1,248 Posts
After reading many posts about shift firmness, I chose level 3 for mine. No big deal -- its not like it turns into a raving beast or something -- just a bit firmer shift. I also added a 490 boost valve and is still not that noticable.
 
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