KHester84

I've been doing tons of research about the GMT-900 aka NNBS style transfer cases. I'm very interested in swapping to a more durable transmission since I am planning on going FI in the near future, the only problem is that not too many people have tried swapping in a 4L80e/6L80e/6L90e on a 4wd platform. I'm hell bent on retaining the 4wd functionality that I paid for when I bought the truck, therefore I need all of the assistance I can get from forum members and maybe some GM techs/sales reps.

In the GMT-900 platform, GM has started putting Magna Powertrain "MP" transfercases in their vehicles as the new transfer case of GM. MP is not new to the game, it is just a new name for NVG, NP, etc, however these new transfercases are different from the older NVG 246/261/263s, etc in both function and design.

I stumbled upon 3 articles from Transmission Digest that go into detail about the new MP transfer case options, ratings, and the like. The first article explains the model numbers, torque ratings, and gives some details about the 1222/1225/1226 models (RPO NQG) and 1625/1626 (RPO NQF). The second article goes into detail about the 3023/3024 models (RPO NQH). The third article discusses the 3023/3024 operational theory and diagnostics within the units.
Article 1 Page 10
Article 2 Page 18
Article 3 Page 18

I have compiled this data into a spreadsheet listed below. I have not found much information about these MP transfer cases on this site, so I wanted to share this information with you all. I have made some guesses as to which transfer case will match with what transmissions, if these seem questionable please chime in.

There is some conflicting information listed in these articles compared with what has been stated on these forums about transmission output shaft spline counts on the 6L90. In the second article, transfer case MP 3024 is claimed to be used with the 6L90 (RPO MYD) transmission, but has a 29 spline input count, and a 31 spline output count...seems weird. I also found a motor trend test drive article that features a 2008 2500 Suburban equipped with a 6.0L engine and 6L80e connected to a MP 3024 transfer case. If this is correct, then the MP 3024 transfer case must be the 6 speed tranny tranfer case, while the MP 3023 is the TC for 4L60/65/70 equipped vehicles. Can anyone confirm the spline counts on a 4wd 6L80/6L90?

Here is my spreadsheet:


I'll be creating another thread that will outline the goals for my transmission swap that will rely heavily on information discussed here.

Cheers
Keith

KHester84

Yall are a hard crowd to please lol.

Anyone have the spline counts from a 6L80/6L90 4x4 model? The output shaft of the transmission, not the transfercase.

Keith

sand man

great thread im very intrested in finding out how much my transfercase can handle

thor72k5

6L80 = 32 splines
6L90 = 34 splines

As I understand it, you can bolt any GM round pattern transfer case to either tranny. This includes the Atlas 2 & 4 speed transfer cases with the same pattern.

sand man

pump for a great thread

mitchellmade

iTrader: (13)

I should be picking up a 6l90e in a week will let you know what i find out

bdubb

iTrader: (2)

Missing the AWD transfer case. NVG149

mitchellmade

iTrader: (13)

that wasn't available in 900 ,was it?

bdubb

iTrader: (2)

You're correct, I had it wrong.

It is a Borg Warner 4485 (BW4485) or RPO NR3

mitchellmade

iTrader: (13)

Is there anyway to set it to cancel out traction control??