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TrailblazerSS
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Discussion Starter · #1 ·
I'm going to be replacing my diff and figured I should do my gear swap while I'm at it.

My question is: What Rpm's did you change your shift points to for cruising and wot?
 

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07' TrailblazerSS
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I don't believe you change anything but your gear setting in the computer and the puter takes care of everything else, UR50SLO did mine while I was finishing cleaning and filling the rear axle and it took him like 5 minutes to plug in and change the setting and he was done. My truck shifts fine and I asked him what he changed and he said just the gear setting from 4.10 to 3.42's and that's it.
 

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Would love to go 3.42's but not sure how well that would be with AWD.
 

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'08 TBSS 2wd
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HPT will auto-correct the shift points when you change the gear ratio/tire size.
 

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Discussion Starter · #5 ·
I don't believe you change anything but your gear setting in the computer and the puter takes care of everything else, UR50SLO did mine while I was finishing cleaning and filling the rear axle and it took him like 5 minutes to plug in and change the setting and he was done. My truck shifts fine and I asked him what he changed and he said just the gear setting from 4.10 to 3.42's and that's it.
Awesome. Thanks for the info!

HPT will auto-correct the shift points when you change the gear ratio/tire size.
Jeez, I thought there was a lot more to it. Good thing I have a friend with HPT who can tune it. Thanks for the help!
 

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2007 TBSS AWD
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BERTO_702; said:
Jeez, I thought there was a lot more to it. Good thing I have a friend with HPT who can tune it. Thanks for the help!

That is the quick and dirty way. If you really want to dial it in you are going to have to get into the part and wot shift tables. :2cents:
 

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secret squirrel
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thats one helluva ratio change.....alot of freeway driving.....???:burp:
 

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secret squirrel
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1900rpms is my guess...:burp:
 

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2007 TBSS 3SS
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Dang that is a big change. Wonder how much MPG he will pick up? I dont care about MPG (truck is mostly in the garage), but its always nice to say you have a 400hp truck and still get 18-20 mpg
I like 3.73's but dont know if i want t swap out gears.
 

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17 miles each way to work. 99.5% freeway.
I drive 30 miles one way to get to work, all highway. I'm really looking into doing this.
 

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What will your rpm's be at at 75mp?
I did the 3.42 change in mine and at 70 MPH it's 1850 RPM and in town driving the 1SS 2WD get's 16.3 for gas mileage and will go around 270 miles, that wasn't empty it was about 1/4 tank left and only put in 16.5 gallons back in the truck.

To me and I will say it again it's been WELL worth it and to me it REALLY hasn't lost a lot of snort out of it like you would think it would!!!!
 

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XPTBSS
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I did the 3.42 change in mine and at 70 MPH it's 1850 RPM and in town driving the 1SS 2WD get's 16.3 for gas mileage and will go around 270 miles, that wasn't empty it was about 1/4 tank left and only put in 16.5 gallons back in the truck.

To me and I will say it again it's been WELL worth it and to me it REALLY hasn't lost a lot of snort out of it like you would think it would!!!!
Hell I don't see why you guys are going thru all this labor for that. I cruise about 65mph on the highway and knock down between 18-20 on the dashhawk. I get about 350 miles per tank and I have a cam and stall. :dunno:
 

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Discussion Starter · #15 ·
Hell I don't see why you guys are going thru all this labor for that. I cruise about 65mph on the highway and knock down between 18-20 on the dashhawk. I get about 350 miles per tank and I have a cam and stall. :dunno:
I think the stall is what's helping your highway mileage.
 

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Well I go 65 to 70pmh as well but I'm only getting 16 at best. I think I need a new tune.
 

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Hell I don't see why you guys are going thru all this labor for that. I cruise about 65mph on the highway and knock down between 18-20 on the dashhawk. I get about 350 miles per tank and I have a cam and stall. :dunno:
A cam and stall is a heck of a lot more work then installing gears, with out me driving around town looking for a front seal gasket it would have taken 2-1/2 hours from start to finish. Your getting 18-20 on highway I'm getting 16.3-4 IN TOWN driving stop light to stop light, You got 350 miles to the tank and again I GOT 270 miles to 3/4 of a tank of IN TOWN DRIVING. My Avalanche with a slight tune not much at all to it with the same gears less cubic inch (5.3 liter) and weighs more is knocking down 21 MPG at 75 MPH, this is why I went and did this to the SS, the SS is lighter more cubic inch to get it moving so this is why I did it and it hasn't disappointed me at all with doing it.
 

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XPTBSS
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A cam and stall is a heck of a lot more work then installing gears, with out me driving around town looking for a front seal gasket it would have taken 2-1/2 hours from start to finish. Your getting 18-20 on highway I'm getting 16.3-4 IN TOWN driving stop light to stop light, You got 350 miles to the tank and again I GOT 270 miles to 3/4 of a tank of IN TOWN DRIVING. My Avalanche with a slight tune not much at all to it with the same gears less cubic inch (5.3 liter) and weighs more is knocking down 21 MPG at 75 MPH, this is why I went and did this to the SS, the SS is lighter more cubic inch to get it moving so this is why I did it and it hasn't disappointed me at all with doing it.
So why not just drive at lower speeds and have the same difference? A cam and stall were the last things I did for gas mileage. Of course I didn't buy an LS2 powered SUV with 4.10 gears weighing in at 5,000 lbs expecting good gas mileage either.
 

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Call da amber lamps
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^^ I've only seen 17mpg 90% highway driving at 65mph to Killeen to Dallas and back. 18-20 is definitely on the higher end of the spectrum as far as gas mileage for these trucks go.
 
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