Chevy & GMC Vans

Hey guys, I'm looking to buy a 2002 AWD van and I'm researching it.

I'm thinking if I do score it I'm going to want to put a 2-speed 'case in it, but I can't find anywhere what the input spline count on the stock case is. Anyone know?

I already have a 23-spline NP231 laying around here and I'm wondering if it would bolt up. I realize there is a lot of electronics to figure out, but if it won't bolt up in the first place, there is no point.

Thanks.

http://www.drivetrain.com/parts_catalog ... stroSafari

According to Drivetrain.com, should be 27 splines.

Another cool link, thanks.

That 27 spline is for the NP136, how about the borg-warner?

And is it 5-bolts or 6 holding it to the tranny?

Thanks again.

The GM light duty 4x4's use 27 spline from a 4L60E (700R4 as well) to the t-case. It doesn't matter what t-case it is. They don't do like Jeep, Dodge and Ford and use 2 different spline counts. The bolt pattern will be 6 bolts at the trans and 5 at the t-case. This is what my 98 AWD was.

So does anyone have a picture of the adapter?

Is it the 5-bolt Texas pattern? Or 5-round?

I found two places I can get 27 spline inputs and retainers for the cases I have laying around, so now just to figure out how to bolt it up.

Thanks guys.

Here are pics...





The transmission side is 6 bolt round pattern.

Here is the BW4472...



Here is the donor NP231C I used. This case was around a 1993.



Here they are side by side.