BW4472 Exploded view, part numbers, cross reference.

[augidog]

I'm converting a like-new rebuilt 4472 which was hooked to a 700R in a custom mid-90's Sonoma, into a bolt-in replacement for mine. I have pics of that, but will start with a couple references I found while trying to figure this all out.

An exploded view with a nice parts list.

BW - 4472 (1).pdf

Exploded view, Borg Warner part numbers.

(1021.53 KiB) Downloaded 12 times

A snippit from an old website.

XB C72 Catalog_ TRANSFER CASE, Assembly - Transmission Supply.pdf

GM numbers, input and output specs, casting numbers

(382.19 KiB) Downloaded 10 times

You have to need to know this info for it to be more than mildly interesting, but I did need to know and it was super helpful.

More on the conversion later.

[MountainManJoe]

Nice. Can you still get parts for these things?

[augidog]

Nice. Can you still get parts for these things?

That's a definite yes and no, and that's where the above info will help, by confirming numbers.

New
Bearing and Seal Kits seem readily available.
Drive and Driven Sprockets.
Output Bushings

Used
Complete junkyard pulls.
Various internal parts.
Housing castings

NO CHAINS new or as a separate used item.

I bought this like-new rebuilt off Ebay.
I needed to replace the long 32-spline output shaft and housing with the short 27-spine output.

s-l500.webp (28.45 KiB) Viewed 356 times

Hunting for those parts, I found this GM NOS Output Assembly in the freaking box!

I bought the correct used output housing, and a tail housing Seal Kit.

Look at the exploded view to see how easy it was to swap the complete output assembly #8.

[sixsix]

I cannot get those links to work right.
It may be the site or it's server instead.
Seems very limiting.

Getting this:

508 Resource Limit is Reached
blah, blah... try again later


EDIT: did finally work, but this 508 thing has been going on for a few days now.

[sixsix]

aug, I have been reading up on the Bravada 'thing', relative to some discussion from years back and recently.
I saved some addys, talking, BW4472, Sy/Ty, NV136/236, different axles, different chains, shaft removals, etc.

And I have 2 questions:
- why, when the front diff is eliminated ( shaft removed ), do you lose the "PARK" setting on the transmission ?
"You'll have to use the Parking Brake to hold ...".
- what about those different axles supposedly needing/requiring that different chain ?

You may have some follow up to your couple of posts from The Other Side. A repost here...?

[MountainManJoe]

@sixsix, the site is constantly under siege from bots. Sometimes they manage to tie it up completely. I'm thinking about changing providers.

[MountainManJoe]

- why, when the front diff is eliminated ( shaft removed ), do you lose the "PARK" setting on the trans ?

I can answer that. The BW4472 transfer case has an open differential inside. (because front and rear axles need to spin at different speeds in a turn)
Did you ever try jacking up the rear end, and notice that when you turn one wheel, the other spins in the opposite direction, even though the driveshaft is stationary? It's the same thing. The park gear (which is in the transmission) only locks one input. The transfer case has two outputs (front and rear driveshafts). As long as one of them is free to spin, the other can too, and so the van will just roll away.

That's how the two outputs are allowed to "differentiate" (turn different speeds) so you can actually take a turn without binding , tire scrubbing and crow-hopping. In fact, with differentials, any inputs can become outputs, and vice versa. To lock the system, you always need to lock TWO inputs/outputs. This is the reason why limited slips differentials exist. As soon as you have one free-spinning output, power will always go there. The limited slip attempts to bias one output to the other.

The BW4472 does have biasing, in the form of a viscous coupling, but it doesn't kick in until you build up some speed. (It's a shear-thickening fluid). So it won't stop until the van starts rolling away very quickly.

[sixsix]

...The park gear (which is in the transmission) only locks one input. The transfer case has two outputs (front and rear driveshafts). As long as one of them is free to spin, the other can too, and so the van will just roll away.

I made an EDIT above to show I meant transmission, not transfer case - sorry.

Why does any vehicle roll at all with or without the front drive shaft - when the transmission is in park ?
EDIT: Is there not a 'Mechanical Connection' to the item that is in Park. Did Vans with AWD have a different park mechanism or was it in the TC ?


ps: thanks for heads up on the bot thing, anything we can do to help push things to better hgts. while "keeping it simple" ?

[MountainManJoe]

Why does any vehicle roll at all with or without the front drive shaft - when the transmission is in park ?

Not any vehicle. Just ones with an open diff inside the transfer case. For example the later vans with the electric TC (NP136 I think) won't do that.
Was my explanation hard to follow?

anything we can do to help push things to better hgts. while "keeping it simple" ?

Not really. It's pretty much on me.
Bots are kind of a fact of life now. But I'm just frustrated with the support I get from the company. It has really gone downhill in the last couple of years. They used to be based in Canada, but now don't even speak English. I've been researching new providers so that I can at least get decent support. But moving providers is a big project, so I just need a good week to sit down and make it happen.

[sixsix]

No, Joe, I am just being extremely hard-headed on that item, but that's OK, OPEN DIFF IN THE CASE seemed to calm me down...


BOTS... "486 guests online now" - LOL rotflmao
At least with Ublock, no ads.

[augidog]

I was going to inquire into how I can be a supporter, and if more support gets more bandwidth.

sixsix...there are no ads here.

I'm composing my thoughts and will try to ask the question about the different chains in the proper light, based on what I know and don't know, later this evening.

[MountainManJoe]

I was going to inquire into how I can be a supporter, and if more support gets more bandwidth.

Yeah. Better hosting package = more resources = a more robust site.
hmm these bots sure do generate more business for them. If I was a web hosting company and wanted customers to give me more money ... we need a tin foil hat emoji

I'll private message you ...

[augidog]

If you want to keep up with this, you'll need those documents I attached.

Using them, I cross referenced some numbers.

The "new" T-case is a rebuilt GM 15960128.
The GM database shows this as built for the 1995 Blazer/Jimmy.
The list I attached also said Bravada.

The casting numbers are the same as my GM15989331 case.
Almost all of the internals are identical.
I changed the rear output shaft assembly and front output flange.
(a few steps later, we also learned we had to swap the input shaft...
while both are 27-spline, the 700R4 and 4L60E outputs (apparently) have different diameters)

I'll be talking about the Chain issue next.

[augidog]

aug, I have been reading up on the Bravada 'thing', relative to some discussion from years back and recently.
I saved some addys, talking, BW4472, Sy/Ty, NV136/236, different axles, different chains, shaft removals, etc.

And I have 2 questions:
- why, when the front diff is eliminated ( shaft removed ), do you lose the "PARK" setting on the transmission ?
"You'll have to use the Parking Brake to hold ...".
- what about those different axles supposedly needing/requiring that different chain ?

You may have some follow up to your couple of posts from The Other Side. A repost here...?

You can still "Park" the transmission. The viscous coupler, being what it is, will not hold if either driveshaft is removed.

I don't know squat about front axles, and I can barely hold my own talking about basic differentials. When someone suggested that different chains might be about the front axle, I inquired with the big guy. Instead of setting me straight, he laughed at me for even thinking it.

There are some technical notes explaining the differences in chains, and it says don't mix chains and vehicles or you'll get bad behavior.

It's ONLY after a lot of drama that I've deduced that the notes refer to putting the wrong chain in the TRANSFER CASE and has nothing to do with the vehicle. Although I don't see different numbers for sprockets, some Ebay listings say "newer version" so I am going with it's the sprockets that must be the difference. I still don't quite understand what's going on, but it's the only logical tech/mech explanation I can come up with.

[MountainManJoe]

Nice photos. Thanks for documenting this. Awesome