L76 4l70e swap, need transfer case help

[jstev4610]

I'll be swapping a 2008 l76 and 4l70e into my grand wagoneer and need some help picking a transfer case. I want to go awd, from what I can find it appears a nvg-149 would bolt right up to the output shaft, I think it's a 27 spline on the transmisison and the 149 takes the same.

 

So I have a couple questions:

 

Am I correct and if so, what should I be looking for one to be pulled off, a 2003 Denali?

 

Is the 149 a good choice for the L76 vortec max with a black bear tune or are there other suggestions? I want to stay away from anything electronic that would require sensor readings.

 

With the 4l70e, is the speed reading wired to the transfer case or the transfer case? If the t/c, does the 149 have a speed output that will connect up with my harness?

 

 

 

I won't have the drivetrain for another 2 weeks so can't look to confirm and want to have everything on hand as early as possible. Any help is highly appreciated, I have been unable to get any locally. I realize there's likely more I am not considering, this is my first swap and really any major dealings with the transmission and transfer case workings.

 

Cheers

James

[BlueAKSSS]

First off welcome to the site and good luck with your project! The 149 does have a speed sensor which should connect to your harness but you could always change the end connector. The transfer case to get would be from a 01-02 Gmc Denali SUV or a 01-06 Denali truck, and of course 03-05 Silverado SS. Don't get a transfer case from a 03-06 Escalade or Denali SUV because they are not the 149 model and instead the electronically controlled Borg Warner AWD case. Hopefully that helps!

[jstev4610]

That's great info, many thanks! Do you happen to know, are the splines the same in each of those years, so if my transmission is a 27 spline then I just need to grand any of those that I can get my hands on? Are there any you know for sure that are a 27 spline? I think I found that the SS's are, curious about the others.

[BlueAKSSS]

That's great info, many thanks! Do you happen to know, are the splines the same in each of those years, so if my transmission is a 27 spline then I just need to grand any of those that I can get my hands on? Are there any you know for sure that are a 27 spline? I think I found that the SS's are, curious about the others.

All NVG-149 transfer cases are the same that I know of, in other words one from a Sierra Denali is the same as the one in a SS. I do not know the spline count but your number sounds right. Maybe someone can verify that has one off there truck or just knows.

[jstev4610]

So just a follow up, the 4l70e is indeed a 27 spline output, and a 2002 escalade 149 transfer case is a 27 spline input.

[zippy]

You are way over-complicating the spline issue. Just look for a transfercase that was factory behind a 60/65/70E type of transmission and it should be compatible. The 149 is a great unit as long as it is a low mileage unit. The 149 uses a viscous coupler limited slip for the center differential and under higher milage they lose their locking ability. The best option if you can find one would be the TBSS transfercase because they use a Torsen limited slip in the center differential which has a much longer life and front/rear locking. From memory both can be ran by simply using the speed sensor outputs. Most Escalades use an open unit for the center differential and use the Stabilitrac system to control power transfer which means their transfercase is designed to send power to the easiest tire to spin and the computer transfers the power by applying the brakes to that spinning wheel. The TBSS and SSS transfercase utilize a limited slip center diff to simply send power to the driveshaft with more traction instead of less.