thunder550

iTrader: (70)

I'm looking into the feasibility of converting my 1/2 ton d-max swap over to full time AWD. Fitment wise, I'm wondering if the NVG149 would bolt up to the Allison, and if the input shaft in the AWD t-case would swap with the one from the Allison (NP1/NVG263 I think?) the same way they do between the 60E and 80E t-cases.

Capacity wise, I read that the NVG149 was rated to 2200 ft-lb. Also wondering if I just divide that number by the 3.10 first gear ratio from the Allison, which would give me just over 700 ft-lbs, which I will probably exceed with the Duramax. I'm not sure if I'd load up the engine/turbo enough to hit peak torque in 1st gear, but if I do that would be toeing the line.

As far as the mechanics of the swap, is it just the transfer case and front diff that need to be swapped? Are there any electronics in the AWD components that need to be wired in?

thunder550

iTrader: (70)

Answered my first question...according to rockauto, the D-max (NP1/NV263) and SS (NP3/NV149) transfer cases both use the same gasket, so the bolt pattern has to be the same.

lsxperformance

iTrader: (2)

Mine has no electronics other than vss, the front diff on awd truck does not unlock and is always on. Unlike the 1/2 ton diff. Pretty simple system really. From what I read is it uses abs to control it. But I'm not sure how that works or if it does anything. Or maybe that activates the abs module when wheels are free spinning. I don't really see the point of doing this tho, if you already have 4x4? Just wondering..

thunder550

iTrader: (70)

Looks like the input gears are different. Probably have to be a custom piece. There was a guy on one of the forums who was making them to mate the nvg149 to the 4L80E but I'm betting there's nothing available for the Allison.

As far as why, 4x4 is only useful when it's engaged. I don't run around on the street with it engaged, and there are times in traffic or whatever where i get on it and end up spinning the rear tires. Keep in mind the rpm range on the dmax is quite a bit lower than on a gasser, and it doesn't take a ton of throttle to spin the tires. Would be really nice to have AWD all the time, idon't have time in those situations to hit the button and wait for it to engage.

skolman91

iTrader: (28)

the 2200ft lb rating is for the viscous coupling im guessing, as for only being able to take 700ft lb im sure it could stand quite a bit more imo. there are definitely people out there making more on them, how many im not sure.
no electronics just vss like mentioned, the front diffs are the same the only difference is the pass side axle and tube. some people just engage the 4wd locking that axle then unplug it before doing the swap and say they do fine. Quite a few people making good power on 4x4's so id tend to believe it, but diesels are all low torque so who knows..
Get a awd axle and tube just in case and lock the stock one and see if lasts, let us know what you find out..
but like you have already figured out, the hardest part would be the input, that wont be cheap.
what about different length driveshafts?

thunder550

iTrader: (70)

With a 2200 ft-lb limit, you have to divide it by the 1st gear ratio of the trans to find the peak engine torque in 1st gear that the t-case could handle. In this case it's 2200/3.1, which is about 709 ft-lb. When the engine is making 709 ft-lb in 1st gear, the transfer case will be seeing 2200 ft-lbs applied. At least that's what makes sense to me. Then there's the other question about whether or not the engine will load up enough in 1st gear to actually make peak torque. I think the idea is worth trying if I can figure out what to do for an input gear.

thunder550

iTrader: (70)

Messaged Eric at Duraburb yesterday and got a response back. He says that the AWD t-case from the 07+ 6L80E trucks will take the planetary input from our NP263 transfer cases. I took a look at the RPO codes from my wife's 2011 Yukon Denali and got NR3, which is a Borg Warner 4485 transfer case.

Here's the diagram of our NP263:


Here's a diagram of the 4485 internals:



I'm having a hard time envisioning what parts would actually swap. The downside to this is that the 4485 acts as an open differential, so all the power will go to the wheels without traction. I guess on the newer vehicles they rely on Stabilitrak's individual brake application to reroute power to the wheels with traction instead of building it into the transfer case like the NV149's viscous coupling. I'm not sure how well something like that would work on a vehicle without any form of traction control. Eric also said he doubted the 4485 could take the torque from the D-max.

FWIW here's a BW 4473 transfer case internals, it's a 65/35 split viscous coupling from the 03+ GMC Savana AWD vans and others



and here's the NV149 from the Silverado SS

thunder550

iTrader: (70)

Here's an application guide for some of the Borg Warner transfer cases
http://www.jameshalderman.com/images...p_chart_BW.pdf

skolman91

iTrader: (28)

I just picked up a spare 4472 the other day. and if the 4473 is comparable like i would assume it is, no way i would put that behind a dmax, they are just really small units.
I would rather pay the $800 for a custom made input, then put alot of time and money into a open type unit and spin one front tire when you go to launch the first time..my 2cents at least

thunder550

iTrader: (70)

Yeah I'm not really interested in the open t-case. I emailed Rockwell Standard Gear last night and got a response back today, he said not to waste the money on the NV149 either, it would never hold. Starting to sound like this isn't a feasible project.