Rear-end swap: 8.6" 10 bolt w/3.08 >> 9.5" 14 bolt w/3.42 + 3.42 swap in 8.25" front (or else)

[5StarCustmSolutns]

Rear axle removal thread: https://www.tahoeyukonforum.com/threads/rear-axle-c-clip-removal-guidance.139472/


My goal is to order all the parts and tools necessary to make this happen by end of business today. Any advice, guidance or humor throughout this will be greatly appreciated.

Friday five days ago was the first time I'd ever seen the inside of a differential, and if I don't get this completed before our new kitchen gets here....I will likely be experiencing living inside a garage for the first time also


Anyone see any must have parts missing from this list? or any more job specific tools I will need?

{edit} -and-

Can anyone verify that I can or can't tell my ECU to make nice with the 3.42's with a Tech 2? Would love to have one but am leaning towards laptop and HP Tuners b/c I have to shut down the AFM and the TCC Lockup in 1st-4th, dial it back in 5th/6th as soon as I'm done with her kitchen; and I'm of belief? Tech 2 can't do the TCC??

 

[Geotrash]

Can't change the TCC lockup or the gear ratio with a Tech 2, unfortunately.

 

[5StarCustmSolutns]

Can't change the TCC lockup or the gear ratio with a Tech 2, unfortunately.

Dang it..

I've got a 68.308mi 9.5 14 bolt tee'd up in your neck of the woods right now.. Well almost in your woods....Roanoke. Have about 20min to make a decision for a Friday pickup. I'll prob wait til morning and go get it Monday. I'm still licking my wounds from getting "got" for $170 right before Christmas on an Escalade instrument cluster . Plus the salesman was trying to pressure me, and thats exact wrong approach to me

 

[Foggy]

You'll need HPTuners to do what you want in the transmission...
Believe Me, It makes a world of difference
I "believe" that you won't need any driveshaft/Ujoint/Pinion changes.. It should all just
bolt in... At least it does in the Yukons. (for the rear end)...
The HPT will do your DOD disable, your speedo (for new gears), and trans shift points
I love my 6L80E with it 'tuned' correctly... Stock it kinda sucked

 

[5StarCustmSolutns]

Had an interesting evening yesterday. I stumbled into the subject of carrier breaks.....and either the site I was looking at parts on was incorrect or I'd accidentally selected the wrong axle assembly to look at parts for? The Front Diff R&P gear prices I was seeing had this huge increase to jump the carrier break and go from 3.08 to 3.42? So I spent the next hour or so hour learning up on what a carrier break was(and what the hottest new winter trout lures are). But thinking about how limited my options just became and how expensive things just got for the front diff, I got aggravated....shut down computer, turned out the lights, and sulked my way in the house determined to sell the truck lol.
Then this morning I found this:

Thick Gears vs. Thin Gears and Axle Carrier Breaks Explained

Crawlpedia is an off-road encyclopedia featuring a detailed explnation of thick and standard ring and pinion gears and how axle carrier breaks work.

www.crawlpedia.com

and it's got a much better description(with visual aids) of what a carrier break is and a list of which common axles have and don't have a break that affects this project.
I must've accidentally selected a GM 8.2 BOP instead of the 8.25 IFS?? That's the only thing I can figure?
Either way that link was relevant enough to this thread to include. Lot of good info on that site period

 

[5StarCustmSolutns]

When I first started using forums I didn't understand why the trend seemed to be to advise new members with questions to go read and find the answer themselves... I was also much younger at the time... After a little experience, I get it.... It's kind of like giving a man a fish and feeding him today or teaching a man to fish and feeding him for rest of his life

But right now, since my truck is on jackstands with differentials removed, I'm in need of a fish....or a really hot lure I can catch one pretty quickly on?

Currently in the middle of this 9.5" 14 bolt 3.42 front/rear swap on my 2011 Avalanche. Yest I purchased an 8.25" IFS 3.42 front diff. It looks like poo but I have it. Yest eve I made arrangements to pick up the 9.5" rear a couple hours from now. I mentioned the front I had just bought and it's condition to the owner of the yard I'm goin to today and he offered me the one out of the donor truck for $100 bones!?!? Told him I was of the belief the 9.25 was NOT a direct bolt up under the front of trucks that came w/8.25?? He says it is... However the yard yesterday said it was not?

So I'm getting conflicting answers from competing salvage yards?

If anyone knows about this, and is certain, would you please share your wisdom:

Is '07-13 9.25" front diff a direct bolt onto my 2011 Av that came w/the 8.25"? -and- If it does bolt on, are there any spline count, axle length/diameter, or hub fitment issues?

Sorry to ask, I'm dizzy from reading about this right now and am running out of time..

 

[avalonandl]

The avalanche (1500) and Tahoe/Yukon are built on the same chassis. Wheelbas is the diffence so mounting points are the same. 2500 a different animal

 

[Geotrash]

When I first started using forums I didn't understand why the trend seemed to be to advise new members with questions to go read and find the answer themselves... I was also much younger at the time... After a little experience, I get it.... It's kind of like giving a man a fish and feeding him today or teaching a man to fish and feeding him for rest of his life

But right now, since my truck is on jackstands with differentials removed, I'm in need of a fish....or a really hot lure I can catch one pretty quickly on?

Currently in the middle of this 9.5" 14 bolt 3.42 front/rear swap on my 2011 Avalanche. Yest I purchased an 8.25" IFS 3.42 front diff. It looks like poo but I have it. Yest eve I made arrangements to pick up the 9.5" rear a couple hours from now. I mentioned the front I had just bought and it's condition to the owner of the yard I'm goin to today and he offered me the one out of the donor truck for $100 bones!?!? Told him I was of the belief the 9.25 was NOT a direct bolt up under the front of trucks that came w/8.25?? He says it is... However the yard yesterday said it was not?

So I'm getting conflicting answers from competing salvage yards?

If anyone knows about this, and is certain, would you please share your wisdom:

Is '07-13 9.25" front diff a direct bolt onto my 2011 Av that came w/the 8.25"? -and- If it does bolt on, are there any spline count, axle length/diameter, or hub fitment issues?

Sorry to ask, I'm dizzy from reading about this right now and am running out of time..

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

 

[randeez]

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

sort of... 2010+ 2500hd axle pretty much bolts in. wouldnt call it a direct swap though

 

[Geotrash]

sort of... 2010+ 2500hd axle pretty much bolts in. wouldnt call it a direct swap though
View attachment 392075
View attachment 392076

That's good to know! Thank you, sir.

 

[5StarCustmSolutns]

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

Thanks for weighing in... I had to delay going to get the axle a few hours to help procure lodging at Snowshoe for the Wounded Warriors Snow Day event we're helping with 3/2-3/5. I've been playing role of reservation coordinator for last 2hrs lol...

Im not 100% it will be the same donor vehicle for the front and the rear? He made it sound that way, however mostly what I heard was that I would get to help pull, and that I would get to see odometer and condition of vehicle with my own eyes!
I did call him back about 830 and ask again about the 9.25 fitting in my truck, and he said yes. He said I was overthinking it. Said Yukon XL, Burban, Esc ESV/EXT, and Av are same chassis. Said take pics of mine to compare, but it will work... I guess we'll see here in a few hours

 

[5StarCustmSolutns]

sort of... 2010+ 2500hd axle pretty much bolts in. wouldnt call it a direct swap though
View attachment 392075
View attachment 392076

This the front diff you got the Cognito spacers for? I went back and Re-read that thread this morning. When I read it the other day I didn't catch that it was 2010+ 2500. Was it a Silverado/Sierra? Is it a 30 or 33 spline?

edit- and is it AWD or 4x4 hi/lo

 

[randeez]

This the front diff you got the Cognito spacers for? I went back and Re-read that thread this morning. When I read it the other day I didn't catch that it was 2010+ 2500. Was it a Silverado/Sierra? Is it a 30 or 33 spline?

edit- and is it AWD or 4x4 hi/lo

yea silverado/sierra 2500/3500,
spline - inside the diff i think are 33? but doesnt really matter youre connecting to the 8 bolt axle stubs.
the 8bolt complete cv axles are 36 spline iirc. cant use them on 1500s or pre-2010 2500s, however gmt900 and pre2010s are same size and both 33 spline at the wheel hubs

and i dont mean 8bolt wheel hubs...connecting to the stub shafts are 6 hole for 1500, 6 bolt for pre2010 2500+ (larger than 1500) and 2010 HD+ are 8 bolts

so you need the 8 bolt inner cup to the 33spline outer.

oem axles you can pull the cv joint off the outer side of both pre/post HDs and swap them making a longer axle with oem parts.
aftermarket axles you cannot swap the cv joint, but you can swap the inner "tripod" cups between the two, but axle shaft between the two is shorter
spacers may not be needed if you use the longer 2010+ shafts and swap the outer joints onto them, but at the time i was only buying aftermarket axles and couldnt so they were short. wasnt looking to spend $300+ on each axle (x4) for oems just to see if it would even work

or call RCV and confuse the fck out of them and they will send you a set after a few tries for $2800 bux

 

[5StarCustmSolutns]

90 minute drive to salvage yard and THERE WASNT ONE 9.25" FRONT NOR ONE 9.5" REAR axle at this place... Despite the fact that I talked to dude 5 times this week, including twice this morning, each time making it crystal clear what I was looking for.....smh

The only thing that kept me from going ballistic was the 77k mi 8.25" w/3.42's in it... Only had 77k miles and was 1/3 the cost of the unit I bought yesterday. It was a good deal but not good enough to make me forget what stupid is..

 

[5StarCustmSolutns]

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

Can't remember who it was,

I'm confused. As far as I know, the 9.25" rear diff with the 6-bolt wheel hub flanges only came on 2WD half-ton Escalades and Denalis because of the higher torque output of the 6.2. If that's true, then I wouldn't expect there to be any front diff in that donor truck. Are you sure that the rear axle you're about to pick up has the 6-bolt hub flanges and came out of a 2WD Escalade or Denali?

And to answer your other question, no, a 9.25" front diff will not fit under a half-ton Avalanche, AFAIK.

Last week while I was reading through one of the threads on here about this axle swap deal, someone(and I just spent about 20min trying to find it)said something along the lines of "make sure the 14 bolts you're looking at buying are not 8.6 3.42 10 bolts being passed off as 9.5 14 bolts". I thought it might've been you? possibly @OR VietVet or @CaptainAmerica1 ?? Either way you've all probably read it at one point....but I remember thinking how could that ever happen? Well, yesterday I saw exactly how. When the yard owner is telling you a ____ is a ____ when it's really a ____. If you don't know your stuff, it's real easy to either roll right out of there with a ____ thinking you've got a ____! Or convince yourself that a ____ is good enough and settle for what's avail.. Then when/if you do figure out that the heat and pressure broke you down, you end up ____ ____ ___ ____ _____'n all the way back to the ___ ___ salvage yard hoping you can still return your part...

Thanks to the foundational work all you guys put down, I was able to hold my ground yesterday....even eventually got a "you were right there is another 3.42 option" out of the guy....

@randeez, @Dantheman1540, @Trey Hardy, @swathdiver , and everyone else who's been a contributor to these axle thread

 

[randeez]

90 minute drive to salvage yard and THERE WASNT ONE 9.25" FRONT NOR ONE 9.5" REAR axle anything at this place... Despite the fact that I talked to dude 5 times this week, including twice this morning each time making it crystal clear what I was looking for.....smh

The only thing that kept me from going ballistic was the 77k mi 8.25" w/3.42's in it... Only had 77k miles and was 1/3 the cost of the one I bought yesterday. It was a good deal but not good enough to make me forget stupid

What year are you working on? Cause I don't think those front axles are for an 07+, the tab on the top is how they mounted up to 06 (07 classic trucks) gmt800s. Gmt900s have two mounting holes right next to the stub shaft on diversside

 

[5StarCustmSolutns]

What year are you working on? Cause I don't think those front axles are for an 07+, the tab on the top is how they mounted up to 06 (07 classic trucks) gmt800s. Gmt900s have two mounting holes right next to the stub shaft on diversside

View attachment 392139

Mine 2011.... Both those are 8.25's.

Not sure what year the one missing it's long tube flange came off of? Didn't see donor. Part was on shelf. Only bought because it was the closest 3.42 to me and literally had to go right past that yard Tue. Also, assured I could go ahead with rear swap and not worry bout having to roll 4x2(in Feb) until I found a 3.42 front. It was the $300 one, gonna return it.

The fully intact(better pic here) one came out of '08 Burban. Was still in truck yesterday. It was only $100.00, and we had just driven 90min to get a 14-9.5" w/a 9.25" IFS that ol dude told me was there, on his Chevy only yard.... only to find out he didn't even know they existed.

I think it just upside down compared to your pic??

Paid $243.80 w/core for 123k mile 14 bolt rear today. It's 150mi away in KY, across river from Cincy. Leaving about 930 or so to go get it.

 

[swathdiver]

Paid $243.80 w/core for 123k mile 14 bolt rear today.

Core?

 

[randeez]

Mine 2011.... Both those are 8.25's.

Not sure what year the one missing it's long tube flange came off of? Didn't see donor. Part was on shelf. Only bought because it was the closest 3.42 to me and literally had to go right past that yard Tue. Also, assured I could go ahead with rear swap and not worry bout having to roll 4x2(in Feb) until I found a 3.42 front. It was the $300 one, gonna return it.

The fully intact(better pic here) one came out of '08 Burban. Was still in truck yesterday. It was only $100.00, and we had just driven 90min to get a 14-9.5" w/a 9.25" IFS that ol dude told me was there, on his Chevy only yard.... only to find out he didn't even know they existed.

I think it just upside down compared to your pic??

Paid $243.80 w/core for 123k mile 14 bolt rear today. It's 150mi away in KY, across river from Cincy. Leaving about 930 or so to go get it.




View attachment 392237

Got it, think you're right

 

[5StarCustmSolutns]

Core?

$150 + $80 core + tax =$243.80. Bessler Auto Salvage Wilder, KY found on car-part.com

Quoted me $235 w/3yr unlimited mile warranty. I figured since putting one of the Torsen style carriers and all new bearings, no need for warranty. He came back $165 w/o warr. I said how bout 150 cash price... he said 150 + tax.. deal