WTB: 325iX Viscous Coupling or Rebuilt TC

[Tarbuster]

Doing a transfer case rebuild and need a viscous coupling, preferably new.
These are NLA from Germany, and all of the US parts houses appear to be cleaned out, but you knew that.

Anybody holding a fresh VC?

Might entertain a used unit if it is coming out of a relatively low miles car, but I'm not sure how anyone would substantiate that mileage factor.

Also:
The mechanic doing the work says the input shaft, part number 27 24 1 227 037 is what's needed to complete the rebuild, but that part is also NLA.
There is a second input shaft listed, at – 039, but I'm unsure if that supersedes the 037 part or not.

Anybody know if those two input shafts are interchangeable?
One parts guy tells me that they both relate to the same TC chain, so they ought to be, and recommends I order the 039.

If I can't find a VC, may need to entertain a rebuilt Transfer Case altogether, also difficult to source currently.
Anybody holding a rebuilt TC?

[nando]

The sprockets must match the chain, but I think the shafts are interchangeable.

It's also possible to rebuild the VC if you can't find one.

[The Dark Side of Will]

Also:
The mechanic doing the work says the input shaft, part number 27 24 1 227 037 is what's needed to complete the rebuild, but that part is also NLA.
There is a second input shaft listed, at – 039, but I'm unsure if that supersedes the 037 part or not.

Anybody know if those two input shafts are interchangeable?
One parts guy tells me that they both relate to the same TC chain, so they ought to be, and recommends I order the 039.

37 is the driven chain sprocket for the front driveshaft output.
39 is the driving chain sprocket at the front of the viscous coupling.

[nando]

Yeah, those have to match the chain.

are you sure those are in need of replacement? I've had a lot of TCs opened up, I've never seen any with significant wear.

[Tarbuster]

From what my TC rebuild guy tells me:
I'm looking for the TC shaft that has the female splines that the fr driveshaft splines fit into. Those internal splines are worn.

He says I'm needing 272 412 270 37 – what he is calling the input shaft.
He may have the numbers mixed up. And I think it's actually an output shaft and it's the 039.

Real OEM diagram:

http://www.realoem.com/bmw/enUS/showparts?id=1293-USA-11-1988-E30-BMW-325ix&diagId=27_0003

The 039 shaft is line item #6. Isn't this actually the shaft with the internal splines which connects to the front driveshaft?
The 037 shaft is line item #29. NLA. I don't think I need that.
The 663 shaft, the only one actually called an output shaft, next to the VC, is line item 18. NLA. I don't think I need that either.

If my female splines are worn, which of those three shafts should I be ordering?
I think it's the 039?

[The Dark Side of Will]

From what my TC rebuild guy tells me:
I'm looking for the TC shaft that has the female splines that the fr driveshaft splines fit into. Those internal splines are worn.

He says I'm needing 272 412 270 37 – what he is calling the input shaft.
He may have the numbers mixed up. And I think it's actually an output shaft and it's the 039.

Real OEM diagram:

http://www.realoem.com/bmw/enUS/showparts?id=1293-USA-11-1988-E30-BMW-325ix&diagId=27_0003

The 039 shaft is line item #6. Isn't this actually the shaft with the internal splines which connects to the front driveshaft?

No. (and 039 is callout #9)

The 037 shaft is line item #29. NLA. I don't think I need that.

That's the one you need.

37 is the driven chain sprocket for the front driveshaft output.
39 is the driving chain sprocket at the front of the viscous coupling.

If my female splines are worn, which of those three shafts should I be ordering?
I think it's the 039?

It's 037.

[rampart05]

TC case front output sprocket

If you need the front output sprocket. I have one in great condition. Nearby in Colorado Springs. Send me a PM

Don

[Tarbuster]

Thanks for squaring me up on that 037 part # and application, Will.

So I found a viscous coupling with 160K on it.
Now it is the 037 output shaft which stalls my TC rebuild. And I see rampart05-Don just came up with one!

...

There is the lesser issue of the actual line item #6: NLA shaft seal 272 112 246 32 (I'm told it's internal to the TC)
I'm thinking I could substitute with: 271 112 263 14 (same seal as listed for the automatic transmission TC: also line item #6) – My TC/iX is a manual trans configuration BTW.

See Real OEM auto trans TC diagram here. Should be the same part, no? Though perhaps it relates to the different housing for the AT TC case as seen on the fr driveshaft side?

https://www.realoem.com/bmw/enUS/showparts?id=1203-USA-08-1988-E30-BMW-325ix&diagId=27_0003

I'm also told that seal can be sourced based on its specification outside of BMW part searches.

...

^^^This question has been answered offline: NO, this particular seal from the manual to the automatic TC is NOT interchangeable. I'm leaving the question up because I think it's valuable for the readers to see the answer. And yes, the 272 112 246 32 can be sourced via its dimension: 32 X 47 X 7.

PM sent, Don.
– Roy

[Edit] nando + The Dark Side of Will : Thanks guys, for all your input! I should be good to go now.

[nando]

An alternative to replacing the whole sprocket is to rebuild the front driveshaft so it engages deeper into the splined section. The splined depth of that socket is at least 1 1/2", but the stock shaft only uses 3/4" of it. So there is still more than enough 'fresh' spline surface to use if you can somehow engage it.

The downside is you need to find somewhere a shaft extension (a guy here made some a while back) that goes deeper into the socket, and you have to drop the transfercase to grease and inspect the splines on the front driveshaft going forward.

BTW, the splines fail because of improper lubrication (it requires a high MOS2 grease that won't wash out or oxidize). Since figuring that out (and using an extended shaft) I haven't had to worry about it in years, and I've beat the crap out of it too.

[Tarbuster]

Yeah, thanks for elaborating that, nando.

Some of you might be familiar with Gordon Haines' iX Registry, a tremendous resource which used to be online. Maybe still is? (I printed the whole thing out. Must be ~300 pages)

In one of the last issues, number 26/28, a guy talks about getting a hold of a fabricator/welder who did that lengthening to his splines. But nando, you just answered something which I was not quite putting together: and that is that it cannot be removed easily for lubrication.

My understanding is that one of the best Moly products for splines, and one that used to be spec'd by BMW and even had a part number, is Molykote 2. That's molybdenum disulfide (MOS2) with lithium.

I ran down the original and superseded PNs of that spline grease and came up with an alternative product called UNIREX 5240. The BMW motorcycle guys use it, and another product by Castrol.

I got my Molykote 2 + from Motion Industries just a couple days ago. They're also a good source for NLA bearings when doing a TC rebuild. 800-526-9328.

Don was just telling me he uses Marine grade Amsoil grease. This might be it:

https://www.ebay.com/p/AMSOIL-Synthetic-Water-Resistant-Grease-14oz-Tube/527117084?iid=283301927066&chn=ps

Here are some threads I found useful in getting my head wrapped around this project:

Testing a TC that's already been pulled from the car:

https://www.r3vlimited.com/board/showthread.php?t=359111

Rebuilding a TC:

https://www.r3vlimited.com/board/showthread.php?t=406860&highlight=Viscous+coupling

Rebuilding a VC:

https://www.r3vlimited.com/board/showthread.php?t=406859

^^^
This third link is the bomb! Except we need someone to take on the task of doing a bunch of them.

Thanks again, guys! This forum rocks.