Need suggestions

[TollKeeper]

So I have decided to upgrade my XUV a bit. Mainly because it doesn't have the power needed to pull my trailer in the mountains. I have the GU6 with G80 axle. So its great for mileage when on interstate, which I never drive unless I am towing my quads/sleds to the mountains. I am not really concerned about my fuel mileage, I just want to be able to go up some up these big mountains at or near speed limit, which my GU6 cant do.

My truck: 2004 GMC Envoy 5.3 with a new GM tranny, and 151k on everything else.

I talked to my local dealer, and they tell me that they can get a file so that I can switch to whatever axle I choose. Is this true?

So I started shopping around, and these are my options
GT4/3.73 with G80 from another XUV
GT5/4.10 with OPEN from a SS
GT5/4.10 with G86
GT5/4.10 with G80

Is the SS/G86 axle going to withstand my truck? I know its recommended not to use the 113 axle on my 129. Is the exception the SS axles?

or... Would I be better off to just put a new ring in my current axle? I can get a 4.10 and just use my G80. Then I would just have to replace the front diff.

Opinions and thoughts?

 

[djthumper]

If you already have the 8.6" rear end I would just upgrade the gearing and then upgrade the front differential, unless you can find the gears for the front.

 

[TollKeeper]

That's the way I am leaning. Just never done gears before. I have done a axle thou. I pretty much have my choice of 3.73. Found them with both the G86 and the G80 here local. The 4.10 would have to be shipped in.

 

[Blckshdw]

not really concerned about my fuel mileage, I just want to be able to go up some up these big mountains at or near speed limit

If budget wasn't an issue, bolt on a supercharger, get a tune, and call it good. Problem solved

 

[TollKeeper]

I didn't say budget, I said fuel economy. I only drive about 100 miles a week. My tank usually lasts a month. I am OK with 2 weeks.

 

[TollKeeper]

So I picked up a rear axle from an 04 envoy xl with 90k GT5 & G80. It was cheaper than a ring and pinion, and who knows, maybe I can make my money back if u sell it. I also picked up half my interior stuff that I am needing to convert to the woodgrain interior. Denali steering wheel, radio bezel, and headlight bezel. Now I just need a center console and gear shift knob.

So now I have a question in regards to the front axle. I can find a whole bunch of GT5's from 02 GMT360. But everyone I have been speaking with say the 02 models only fit the 02 trucks. Any truth to this?

Waiting for winter to end to put in the difs. Still waiting for the dealer to tell me the got the new batch file from gm.

 

[Mooseman]

Playing around on car-part.com, 2002 seems to be a bastard year where they ask if there are one or two mounting bolts below and forward of the yoke. Two bolts I get all years whereas one bolt I get only 2002.

 

[TollKeeper]

Next question is, I have been reading up on all the front differential removal procedures, and all the write ups are on the 4.2. I have the 5.3, and wonder if there are changes to the procedure. Obviously, coming out the top isn't going to happen.

 

[Mooseman]

The vast majority have the 4.2 and haven't seen anything about the V8. Hope you don't have to remove the oil pan. That's how I'd do it if there was no other way.

 

[TollKeeper]

I remember pcmofnc saying they could not do anything about great ratios. But the dealer can? I'm confused.

 

[Mooseman]

I have a theory that the gear ratio is tied to the VIN when the PCM is first programmed. So by programming the PCM via the Tech 2 and Tis2000 with the VIN of a truck with the desired gear ratio should work.

It's a spring project that I want to do to prove this.

 

[TollKeeper]

Sweet! I got a GT5 G80 rear dif and a GT5 front diff paid 600 for both. 82k miles on the front, and 90keep on the rear.

Next question is the front diff came from a SS. Will the disconnect bolt up and work the same?

 

[Mooseman]

Should. It bolts to the oil pan. On the SS, there would be a AWD type without an actuator.

 

[Sparky]

You have a 5.3, there is no issue programming the gears or tire size changes on that engine as the PCM is the basically the same as other V8 vehicle models of that year range (full size trucks, even the fbody with the LS1, etc).

The gear ratio programming limitation is on the 02-05 inline 6 GMT360 trucks. That PCM is the oddball one.

 

[TollKeeper]

So can the gear ratios be changed via the tech2, or does a new batch file need to be imported in?

 

[Mooseman]

I'm not sure but @limequat should be able to answer you.

 

[limequat]

What sparky said. You can do it with a tech II if you can find a dealer to cooperate. Might be easier to get a tuner -ahem- to help out. That way you fix the ratio and get a tune too!

 

[TollKeeper]

Lime, how much does something like that cost?

 

[Mooseman]

Check his signature

 

[TollKeeper]

I'm mobile. Can't see it lol. Don't know how to get to it either.

 

[djthumper]

$99

 

[Denali n DOO]

I'm mobile. Can't see it lol. Don't know how to get to it either.

Turn your phone sideways and you'll see signatures...

 

[TollKeeper]

Question on the rear axle. on the SS G86 axle, do they have the same calipers, mounting brackets, e-brake, etc, as the non SS G86 axles . basically, is it the same axle just 9.0 vs the 8.6?

 

[TollKeeper]

And another question, will the ABS sensors hook up the same?

 

[Mooseman]

Yes and yes.