2WD to AWD Conversion 07

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?

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@NickTransmissions Nick will know if the output shaft on the 4L60 has to be changed if converting from RWd to 4WD, I'm pretty sure it does but don't remember. As for the frames, it is possible that the holes are there but need to be tapped, seen that before. Stop by the house and compare mine to yours.

The LSDs have clutches and springs that wear out faster under continuous duty in a truck that weighs 2-3x as much as a car. The truck G80 is a hybrid, it is basically a locking limited slip, it too has clutches but of course they are not engaged all the time which is why they typically last the life of the vehicle. When I was looking at different brands of limited slips, they all prominently mentioned being rebuildable and that set off a warning in my little brain. Then I read the comments which confirmed that they are a high maintenance item. Works if you want it but the mean time between failure is higher than the G80.

Mine averages (whole tank) about 11 mpg around town on E85 and 14 on the highway so you're doing good compared to mine.

Doubeleive said:

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

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Wes, the 2007-2009 trucks and SUVs could have had non-flex fuel engines, the LH6 (pickups only) and the LY5. The 6.0 L76 used from 2007-2009 was not FlexFuel and you know about the L92 being straight gas as well.

swathdiver said:

@NickTransmissions Nick will know if the output shaft on the 4L60 has to be changed if converting from RWd to 4WD, I'm pretty sure it does but don't remember.

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Hey @swathdiver, if you mean converting a 2WD to 4WD/AWD then yes, trans has to come out, be taken half way apart so you can swap the 2WD output shaft out for the 4WD shaft on all 700R4s and 4L60Es and frankly all GM transmissions AFAIK.

NickTransmissions said:

Hey @swathdiver, if you mean converting a 2WD to 4WD/AWD then yes, trans has to come out, be taken half way apart so you can swap the 2WD output shaft out for the 4WD shaft on all 700R4s and 4L60Es and frankly all GM transmissions AFAIK.

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Thanks Nick, that's what I thought. Will the 4L60 bolt up to a Borg Warner 4485 transfer case with the same adapter?

So there's that too @dwinters14

Oh, the 4x4 and AWD front differentials are different internally too, not just on the one side. So make sure you get an AWD front differential from an Escalade or Denali.

swathdiver said:

Thanks Nick, that's what I thought. Will the 4L60 bolt up to a Borg Warner 4485 transfer case with the same adapter?

So there's that too @dwinters14

Oh, the 4x4 and AWD front differentials are different internally too, not just on the one side. So make sure you get an AWD front differential from an Escalade or Denali.

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You're welcome...I think the 4485 uses a 32 spline input for pairing with 4L80s and 6L80s 32-spline outputs while the 4L60Es all use 27-spline output shafts...

NickTransmissions said:

You're welcome...I think the 4485 uses a 32 spline input for pairing with 4L80s and 6L80s 32-spline outputs while the 4L60Es all use 27-spline output shafts...

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Okay this leaves me with a couple of questions. The 4L60E AWD transfer case from the GMT800 is the NV149, which should bolt up to the 27 spline no problem. The AWD transfer case from the GMT900 is the 4485, that has the 32 spline input shaft for the 4L80.

LT on youtube did a 4L80 trans swap on a GMT800 drivetrain by changing out the input shaft to accommodate the newer trans. Can the same not be done on the 4485? Or simply use the NV149 with the Denali/Esky front end? He did a few modifications to make it fit, but I don't think he had to gut the trans at all.

dwinters14 said:

Okay this leaves me with a couple of questions. The 4L60E AWD transfer case from the GMT800 is the NV149, which should bolt up to the 27 spline no problem. The AWD transfer case from the GMT900 is the 4485, that has the 32 spline input shaft for the 4L80.

LT on youtube did a 4L80 trans swap on a GMT800 drivetrain by changing out the input shaft to accommodate the newer trans. Can the same not be done on the 4485? Or simply use the NV149 with the Denali/Esky front end? He did a few modifications to make it fit, but I don't think he had to gut the trans at all.

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No idea who/what "LT" is but you can take a look at a diagram or service manual for a BW4485 and or NV149 to see what may be possible and how to, if modifying the 4485 with parts from the 149 to meet your needs is feasible.

I don't work on too many t-cases as most of the time it costs much more to rebuild them than to buy a good used one.

As far as gutting the trans, if someone converted a 4L80 from a 2WD unit to a 4WD unit, he would have had to completely disassemble that transmission, swap output shafts, remove the rear pin hole seal and replace it with the 4WD cup plug at the rear of the case.

NickTransmissions said:

No idea who/what "LT" is but you can take a look at a diagram or service manual for a BW4485 and or NV149 to see what may be possible and how to, if modifying the 4485 with parts from the 149 to meet your needs is feasible.

I don't work on too many t-cases as most of the time it costs much more to rebuild them than to buy a good used one.

As far as gutting the trans, if someone converted a 4L80 from a 2WD unit to a 4WD unit, he would have had to completely disassemble that transmission, swap output shafts, remove the rear pin hole seal and replace it with the 4WD cup plug at the rear of the case.

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He was on Powerstroke tv I think as well where they did another AWD conversion on a Silverado. This video only centers on the transfer case and changing the input shaft. I don't believe he talks about the 4L80 and what's been done to it.

dwinters14 said:

He was on Powerstroke tv I think as well where they did another AWD conversion on a Silverado. This video only centers on the transfer case and changing the input shaft. I don't believe he talks about the 4L80 and what's been done to it.

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Ok, you mentioned not having to tear into the transmission in your last:

dwinters14 said:

He did a few modifications to make it fit, but I don't think he had to gut the trans at all.

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So wanted to clear up any misundersrandings about that.

I can't tell you what, if anything, specifically you could do to modify those transfer cases to meet your needs as I dont work on those tcases...Perhaps you can post a question in the above video's comments section to see if the channel or someone can provide you the particulars...

NickTransmissions said:

Ok, you mentioned not having to tear into the transmission in your last:

So wanted to clear up any misundersrandings about that.

I can't tell you what, if anything, specifically you could do to modify those transfer cases to meet your needs as I dont work on those tcases...Perhaps you can post a question in the above video's comments section to see if the channel or someone can provide you the particulars...

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No worries man! I appreciate your input on the output shaft and trans info which definitely points me in the right direction. I'm going to do my homework on the T-cases and trans compatibility and see what makes the most sense. I'm hoping I'd just need a custom input shaft with the right splines to make them compatible. If the output shaft is too short or something else then yes, I'd be in a whole heap of poo.

dwinters14 said:

No worries man! I appreciate your input on the output shaft and trans info which definitely points me in the right direction. I'm going to do my homework on the T-cases and trans compatibility and see what makes the most sense. I'm hoping I'd just need a custom input shaft with the right splines to make them compatible. If the output shaft is too short or something else then yes, I'd be in a whole heap of poo.

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You're welcome..If you cant find a compatible transfer case input coupler, you may need a special output shaft from Advance Adaptors or a similar company to be installed in the trans in place of the oem shaft. I build 4L60Es for a variety of specialized 4x4 applications that call for the installation of a custom output shaft to mate with either a different GM factory tcase, another vehicle manufacturer's tcase or aftermarket tcase like Atlas units...