[FastGas]

Alright gents, I recently picked up an all-original 08 EXT with 54k miles on it. I've ordered the whipple 2.3 kit for it along with a few other misc mods (Wilwood BBK front and rear, PML deep trans pan, B&M custom milled diff cover, valve covers with coil mounts, accel coils, 10.5mm wire set, catted LTs, oil cooler adapter, 3 row rad with integrated oil and trans coolers, etc). I'm mainly curious what the group would recommend for trans tuning and or mods to accept the increased power. This will not be used as a hooligan vehicle but it will be asked to tow a 3 place jet ski and motorcycle trailers (approx 3000lbs max) and be a fun weekend vehicle.

 

[FastGas]

I also wanted some input on swapping to 3.73s from the 3.42s. I wasn't very impressed that the 6.2 likes to hunt between 4-5-6 on the highway and between 5-6 around town when encountering small hills. I'm hoping the whipple will help that somewhat but I know gears with the 22s can make a definite impact.

 

[EricVonHa]

Hi there, the tooning aspect is all LS-based. So, whether you are a do-it-yourself kinda person or want to get one of the performance shops to tune it for you.. tons of options out there because there's millions of these LS-based GM motors are in everything.

Your truck is all wheel drive, yes? Not sure what is out there for the front axle gear change, but converting to 2WD opens up all options for the rear end. Any competent speedshop should be able to do it.

 

[FastGas]

Hi there, the tooning aspect is all LS-based. So, whether you are a do-it-yourself kinda person or want to get one of the performance shops to tune it for you.. tons of options out there because there's millions of these LS-based GM motors are in everything.

Your truck is all wheel drive, yes? Not sure what is out there for the front axle gear change, but converting to 2WD opens up all options for the rear end. Any competent speedshop should be able to do it.

The engine tuning is straightforward, I'm more concerned with the trans. I have heard tell that there is an updated, OEM 6L80E calibration that came out around 2014 which vastly improves longevity and overall behavior. I doubt this truck has had that update installed since it has basically been in a car collection since new. I also hear a lot of chatter on a TC upgrade that should be at the same time....

Yessir, it is AWD. Yukon lists a 3.73 ring and pinion set for the front since it uses the standard GM IFS diff:

StackPath

I understand this will most most likely require some recalibration of the ECU to cope with the RPM changes. 3.73s would yield about 200 more rpm across the board.

 

[Cad-driver]

Hi FastGas,

Welcome to the forum! This sounds like a lot of fun! Please keep us updated. I know that takes extra time/effort but, it sure sounds interesting!

 

[SpyShops NY]

You got pics of the interior?

 

[FastGas]

You got pics of the interior?

It's just wood/black leather in really nice shape. The only wrinkle is the nav doesn't work and the disc is pretty beat up which I assume means the reader/player is junk.

 

[petethepug]

The s/c s/w is going to tune the motor. Not sure if it comes with a trans tune incorporated into the package your purchasing. Blackbear is a popular tune that requires $2-$4 worth of tuner developed SW communication devices purchased along with their tune. I’d give them a call and first crack at your plans before you purchase any kits.

There’s info to drop in a pre loved OEM 2011+ VCIM/OnStar module & SD card based Navi without reprogramming the theftlock feature if you want to upgrade to 2014 equip.

The SW will provide factory BT, cell phone remote start, lock/unlock & upload directions from cell to truck Navi, one touch up/down windows front & one touch down in back plus 5/10 other updates. There’s also a solution for integrated A2DP BT music streaming that has a 5 min install.

XLNT choice for a build platform at that milage & zero AFM to deal with. Do you know if the whipple kit will want larger injectors? Texas Speed is another XLNT source for parts and knowledge base for gearing.


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[SpyShops NY]

It's just wood/black leather in really nice shape. The only wrinkle is the nav doesn't work and the disc is pretty beat up which I assume means the reader/player is junk.

I do have a spare 6 CD/DVD changer drive and navigation drive as well from a 2008. I also have a v.2015 nav disc which is the last version made in 2015.