2WD to AWD Conversion 07

wjburken said:

The Denali’s came with full time AWD.

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They're $500 used, but don't the Denali's come with the 6.2's? Looks like a 6L80, not sure the compatibility of the splines on the input shaft. I bet it's the same with the Esky's as well. Hmm....

I have a feeling that if you choose the rear limited slip differential that suits your taste and desires best, you may not need AWD nearly as often as you'd like to have it.
(I LOATHE my so-called G80 - an open diff over 25MpH that stays locked after I want it to unlock.)

The same probably goes for your tires.

All that said - even though I'm not sure if you can junkyard-source everything - I'm sure we'll all learn a lot from your research and experiences ...

if you want traction just get a awd denali or escalade and save yourself a whole bunch of trouble.
every 3-4 month's someone else comes along with the idea to do it. there is a bit more involved than you think.
this truck thread goes over some of it, this guy list's parts he used but doesn't mention any of the electrical part



I converted my 08 Silverado 2wd to AWD. I used my existing 2wd 4l80 and had it converted to 4wd.

These are the parts I bought:

Front differential from an 08 Escalade
CV shafts
GM 8.25 IFS ring and pinion 3.73 (all newer awd fronts diffs are 3.42)
Front driveshaft from the 08 Excalade
Rear driveshaft from an 06 4x4 RCSB
NP149
32 Spline input for the NP149
4wd output for the 4l80e
4wd marriage adapter for the 4l80e to the NP149
2 front bearing hub assembly (steering knuckle is the same for 2wd and 4wd).

Things that were fabricated:
Front differential brackets
cross-member

ON GMT900 trucks the frame is the same. It is even notched for the front differential brackets. I test drove a 4wd truck and put it on the rack and measured where the brackets needed to be.

Everything bolted right in place. My Kooks headers even cleared. I did most of the work myself. My brother helped with the grunt work. A friend swapped out the 4l80 output shafts for me. My dad built the brackets and modified my cross-member (again it was already changed for the 4l80). If I had all the parts handy, I could do it in less than a day. The hardest part was getting all the parts.

My truck weighed 4680 after my first mod (Vortech Twin screw). It now weighs 4900. I'm up 220 lbs, but I've done a ton of modding.

I can tell you love the Burb. You could buy any wrecked 07-14 Esky AWD or YXL Denali AWD and have every part you need to do the swap plus and exact example of where everything goes.

I came from an 02 6SP M Audi allroad wagon w/ 3rd row seat to a 06 YXL Denali (4SP & 6.0L), 08 YXL Denali AWD & lastly a 09 Esky AWD. Of course all Denali / Esky are AWD except in 09+ they had a 2WD option. All 07-14 (NNBS) are 6.2L. All NNBS Denali & 07/08 Esky have z55 Autoride. All 09-14 Esky have z95 MagRide.

You really need to stop at some kind of a GM dealer and test drive a used NNBS Denali or Esky. The AWD connects the 400hp drive train and suspension in a way that only a test drive can explain. It’ll shame the ride of the 4SP & 2WD 5.3 AFM motor in the Burb, which is already a nice ride.

07 & 08 AWD Esky (403hp) & Denali (385hp) do not have AFM like the Burb and it’s a 300k+ mile motor. 09 Esky & Denali (both 403hp) are hard to find but have the L9H, non AFM, e85, one year only 6.2L. That’s why I swap’d from my 08 to an 09.

You’re not in a hurry so go jump in an 07-09 AWD Escalade w/ a/c cooled seats or 09 AWD Denali w/ those same front seats and see what it’s like to drive an 87k or $68k (when new) vehicle that can be had for 13-$19k. Your Burb is in high demand for trade and you’ll want to step away from the AFM motor ASAP. I found my 09 Esky in TX and drove it to SoCal. It cost $1,400. more to trade over from the 08 Denali to the 09 Esky.

Food 4 thought.

put a Posi in it and a fresh set of tires. before going down the rabbit hole is my 2 cents.

does the awd transfer case have a viscous coupling? I think that's the one you'd need for not involving the computers. the 4wd like mine has clutches for auto mode, as I understand it, it's basically 2wd in auto, till it sees wheel slip and then engages clutch pack to sent power to the front. so I think you'd need computers involved with that one.


there's an old power block TV show episode about putting the nbs awd into a old obs 90s truck. for it to work like I think you're looking for your need something like that but from the newer Gen so all bolted in.

Marky Dissod said:

I have a feeling that if you choose the rear limited slip differential that suits your taste and desires best, you may not need AWD nearly as often as you'd like to have it.
(I LOATHE my so-called G80 - an open diff over 25MpH that stays locked after I want it to unlock.)

The same probably goes for your tires.

All that said - even though I'm not sure if you can junkyard-source everything - I'm sure we'll all learn a lot from your research and experiences ...

Click to expand...

I honestly do as well. I've driven in snow for years with RWD. The LSD makes a huge difference, and can do most normal things. I'm just thinking down the road, knowing I have the capability would open a ton of possibilities of use for my Burb.

Doubeleive said:

if you want traction just get a awd denali or escalade and save yourself a whole bunch of trouble.
every 3-4 month's someone else comes along with the idea to do it. there is a bit more involved than you think.
this truck thread goes over some of it, this guy list's parts he used but doesn't mention any of the electrical part

We need a 2WD to 4WD/AWD thread - PerformanceTrucks.net Forums

GMT 900 Trucks General Discussion - We need a 2WD to 4WD/AWD thread - I know there is at least one member here who has done this.. I know from crawling under both at a lot that the 2wd and 4wd/Awd share alot of the front suspension.. Just kind of wanted to get an official thread.. See if anyone...

www.performancetrucks.net

I converted my 08 Silverado 2wd to AWD. I used my existing 2wd 4l80 and had it converted to 4wd.

These are the parts I bought:

Front differential from an 08 Escalade
CV shafts
GM 8.25 IFS ring and pinion 3.73 (all newer awd fronts diffs are 3.42)
Front driveshaft from the 08 Excalade
Rear driveshaft from an 06 4x4 RCSB
NP149
32 Spline input for the NP149
4wd output for the 4l80e
4wd marriage adapter for the 4l80e to the NP149
2 front bearing hub assembly (steering knuckle is the same for 2wd and 4wd).

Things that were fabricated:
Front differential brackets
cross-member

ON GMT900 trucks the frame is the same. It is even notched for the front differential brackets. I test drove a 4wd truck and put it on the rack and measured where the brackets needed to be.

Everything bolted right in place. My Kooks headers even cleared. I did most of the work myself. My brother helped with the grunt work. A friend swapped out the 4l80 output shafts for me. My dad built the brackets and modified my cross-member (again it was already changed for the 4l80). If I had all the parts handy, I could do it in less than a day. The hardest part was getting all the parts.

My truck weighed 4680 after my first mod (Vortech Twin screw). It now weighs 4900. I'm up 220 lbs, but I've done a ton of modding.

Click to expand...

Here's the thing about the Denali's and Esky's. As great as the 6.2L is, I have zero interest in paying $5/gal + for premium gas. I also use my Burb as a work truck and exclusively use E85, so all the fancy luxury items I honestly could care less about. Just more sh*t to break. So long as I have heat/air conditioning, and a good sound system the rest is moot to me.

I did notice that people feel that way. I wasn't naive when buying the burb 2WD, as it's done what it needs to do for my intended use, and I also don't trust that people would have taken care of the drivetrain properly. Now I'm seeing things I feel need to be changed to make the truck work the way I think it should. Looking at your list really affirmed what I need, which is in line with what I was thinking. I appreciate the breakdown.

petethepug said:

I can tell you love the Burb. You could buy any wrecked 07-14 Esky AWD or YXL Denali AWD and have every part you need to do the swap plus and exact example of where everything goes.

I came from an 02 6SP M Audi allroad wagon w/ 3rd row seat to a 06 YXL Denali (4SP & 6.0L), 08 YXL Denali AWD & lastly a 09 Esky AWD. Of course all Denali / Esky are AWD except in 09+ they had a 2WD option. All 07-14 (NNBS) are 6.2L. All NNBS Denali & 07/08 Esky have z55 Autoride. All 09-14 Esky have z95 MagRide.

You really need to stop at some kind of a GM dealer and test drive a used NNBS Denali or Esky. The AWD connects the 400hp drive train and suspension in a way that only a test drive can explain. It’ll shame the ride of the 4SP & 2WD 5.3 AFM motor in the Burb, which is already a nice ride.

07 & 08 AWD Esky (403hp) & Denali (385hp) do not have AFM like the Burb and it’s a 300k+ mile motor. 09 Esky & Denali (both 403hp) are hard to find but have the L9H, non AFM, e85, one year only 6.2L. That’s why I swap’d from my 08 to an 09.

You’re not in a hurry so go jump in an 07-09 AWD Escalade w/ a/c cooled seats or 09 AWD Denali w/ those same front seats and see what it’s like to drive an 87k or $68k (when new) vehicle that can be had for 13-$19k. Your Burb is in high demand for trade and you’ll want to step away from the AFM motor ASAP. I found my 09 Esky in TX and drove it to SoCal. It cost $1,400. more to trade over from the 08 Denali to the 09 Esky.

Food 4 thought.

Click to expand...

They're cool, but not for me at this particular moment in time. I'm also not too concerned about the AFM. It's on my list of things to do, along with an upgraded cam and maybe some head work. I do all my own work on my vehicles and GM trucks have been a godsend, as they are a lot easier to work on than vehicles I've had in the past. Knock on wood my engine is quiet as a whisper when on, so I pray I don't drop a lifter before I can do the delete myself. Also $13k just for AWD doesn't seem worth it when I can do the conversion for probably less than half if I go with used parts.

j91z28d1 said:

put a Posi in it and a fresh set of tires. before going down the rabbit hole is my 2 cents.

does the awd transfer case have a viscous coupling? I think that's the one you'd need for not involving the computers. the 4wd like mine has clutches for auto mode, as I understand it, it's basically 2wd in auto, till it sees wheel slip and then engages clutch pack to sent power to the front. so I think you'd need computers involved with that one.


there's an old power block TV show episode about putting the nbs awd into a old obs 90s truck. for it to work like I think you're looking for your need something like that but from the newer Gen so all bolted in.

Click to expand...

I watched the episodes with LT Matt along with his AWD conversion on his silverado which is what really made me want to do it, as it seems really simple. Relatively speaking. A rear posi is my next step. I'll probably feel it out, and start sourcing the parts needed for the AWD conversion.

dwinters14 said:

I honestly do as well. I've driven in snow for years with RWD. The LSD makes a huge difference, and can do most normal things. I'm just thinking down the road, knowing I have the capability would open a ton of possibilities of use for my Burb.

Here's the thing about the Denali's and Esky's. As great as the 6.2L is, I have zero interest in paying $5/gal + for premium gas. I also use my Burb as a work truck and exclusively use E85, so all the fancy luxury items I honestly could care less about. Just more sh*t to break. So long as I have heat/air conditioning, and a good sound system the rest is moot to me.

I did notice that people feel that way. I wasn't naive when buying the burb 2WD, as it's done what it needs to do for my intended use, and I also don't trust that people would have taken care of the drivetrain properly. Now I'm seeing things I feel need to be changed to make the truck work the way I think it should. Looking at your list really affirmed what I need, which is in line with what I was thinking. I appreciate the breakdown.

They're cool, but not for me at this particular moment in time. I'm also not too concerned about the AFM. It's on my list of things to do, along with an upgraded cam and maybe some head work. I do all my own work on my vehicles and GM trucks have been a godsend, as they are a lot easier to work on than vehicles I've had in the past. Knock on wood my engine is quiet as a whisper when on, so I pray I don't drop a lifter before I can do the delete myself. Also $13k just for AWD doesn't seem worth it when I can do the conversion for probably less than half if I go with used parts.


I watched the episodes with LT Matt along with his AWD conversion on his silverado which is what really made me want to do it, as it seems really simple. Relatively speaking. A rear posi is my next step. I'll probably feel it out, and start sourcing the parts needed for the AWD conversion.

Click to expand...

my Denali runs on e85, currently running 92/e85 50/50 mix

dwinters14 said:

I've been doing research on doing an AWD conversion on my '07 Suburban. So far there hasn't been any clear answers or a process for the GMT900 series SUV's although I'm sure it's almost identical to the GMT800. I hate the traction the RWD has with A/T's even in the rain so I'm going to put an LSD in the rear end at some point, but I wonder if I should just bite the bullet and do the whole thing.

So far the consensus has been to buy an already 4WD truck. I will not do that for 2 reasons, firstly, I don't think it's nearly as difficult or expensive as everyone claims. A trip to the junkyard and I can fully pull all the components off of a totalled 4WD truck and most likely do the swap in a weekend.

Secondly, I do not like the variability of the OEM "4 Wheel Drive" system, so I will not need to involve computers or any modulation from the ECM of the car. I'm going to gut the diffs and put full time LSD's in the front and rear so I have true AWD all the time. I really only need the transfer case, CV axles, drive shafts, Diff housing and I guess a cross member.

Does anyone know which model truck would have the components I would need to get this done? NV149 seems to be the transfer case for the GMT800's but I'm not entirely sure it'll work perfectly with the GMT900's.

I'm also quite shocked this isn't more common? Seems like more vans get these conversions but our trucks don't.

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LSDs in a truck need rebuilding often, they don't last like a G80 does. There is no LSD for the front differential. GM only recently introduced a lock in the new ZR2 trucks but I've yet to see one backfit into our older trucks, not really needed 99.9% of the time anyway.

Do you have the 5.3 or 6.0 engine? The transmission tailshaft and output shaft have to be changed to mate with a transfer case.

GM uses the Borg Warner 4485 transfer case for AWD operation in the Denalis and Escalades. I do not know how or if it will mate to a 4L60 or 4L70 as GM mates it to the 6L80 in all applications in this generation.

The frames between RWD, AWD and 4WD trucks all have different part numbers though I do not know what the differences might be. You can see a frame swap on VEHCOR's YouTube channel, where he swaps an AWD frame to a 4x4 Yukon and talks about the differences a little.

Such a swap also requires differential brackets and 4x4 hubs. To keep the trucks balanced properly, GM would use aluminum engines on 4x4 suburbans and iron block motors for the RWD trucks. They also used aluminum lower control arms but I've yet to decipher the reasoning as to when they would be used.

The 6.2 in my pickup is more fuel efficient around town than the 5.3 in my Yukon XL.

Doubeleive said:

my Denali runs on e85, currently running 92/e85 50/50 mix

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Yes you did say that, but it was a specific year no?

swathdiver said:

LSDs in a truck need rebuilding often, they don't last like a G80 does. There is no LSD for the front differential. GM only recently introduced a lock in the new ZR2 trucks but I've yet to see one backfit into our older trucks, not really needed 99.9% of the time anyway.

Do you have the 5.3 or 6.0 engine? The transmission tailshaft and output shaft have to be changed to mate with a transfer case.

GM uses the Borg Warner 4485 transfer case for AWD operation in the Denalis and Escalades. I do not know how or if it will mate to a 4L60 or 4L70 as GM mates it to the 6L80 in all applications in this generation.

The frames between RWD, AWD and 4WD trucks all have different part numbers though I do not know what the differences might be. You can see a frame swap on VEHCOR's YouTube channel, where he swaps an AWD frame to a 4x4 Yukon and talks about the differences a little.

Such a swap also requires differential brackets and 4x4 hubs. To keep the trucks balanced properly, GM would use aluminum engines on 4x4 suburbans and iron block motors for the RWD trucks. They also used aluminum lower control arms but I've yet to decipher the reasoning as to when they would be used.

The 6.2 in my pickup is more fuel efficient around town than the 5.3 in my Yukon XL.

Click to expand...

I have the 5.3 Flex. I figured something would have to change to work with the transfer case. I'd rather modify the transfer case input shaft than touch the 4L60. Looks a million times easier to rebuild.

Interesting about the blocks and frames, I've seen it said around the internet. Probably not a big deal for my application, even if custom brackets have to fab'd up. I get about 12-14 MPG's right now with E85 doing mostly city driving, which is garbage but it's less than $3/gal, and it's far peppier so it works.

Why do the LSD's have to be rebuilt so often?

dwinters14 said:

Yes you did say that, but it was a specific year no?

I have the 5.3 Flex. I figured something would have to change to work with the transfer case. I'd rather modify the transfer case input shaft than touch the 4L60. Looks a million times easier to rebuild.

Interesting about the blocks and frames, I've seen it said around the internet. Probably not a big deal for my application, even if custom brackets have to fab'd up. I get about 12-14 MPG's right now with E85 doing mostly city driving, which is garbage but it's less than $3/gal, and it's far peppier so it works.

Why do the LSD's have to be rebuilt so often?

Click to expand...

unless I am mistaken i think most 07-14 1500 suv's are flex-fuel no matter the engine size, haven't really did a run-down of which do and do not.
gm was getting epa credits for having it during these years. things changed in 2016
from what I have been reading people were not aware there vehicles could use e85 and so they started putting the flex-fuel badge them to make it more visible, it will always indicate the option inside the fuel cover door if equipped and may have a yellow gas cap, not all e85 vehicles had a yellow cap though