Worn out T-case chain

[The Dark Side of Will]

My dad's '91 iX automatic (Lasurblau 4 door) recently started clunking with heavy throttle like it had stripped splines.

We snagged Jute91's replacement shaft fitting and had a local machinist make/weld a BMW 4 bolt flange onto it (pics to follow).

I tried to change it out yesterday, and found that the splines on the driveshaft and in the sprocket were in fantastic shape and basically not worn at all... uh-oh. I re-greased the splines and reassembled.

It looks like the chain is shot in the T-case.

RealOEM says that the chain should be replaced with both sprockets. I have my doubts about that, as the chain wears out by the pins and pin holes wearing and wallowing out. There's high contact loading on those parts, so that's expected. The sprocket should have much lower contact loading where it touches the chain, so I would expect that the sprocket could still be fine while the chain might be worn out.

Searching for the part number finds listings from the usual suspects in the range of $950. I @$$ume this is just the chain, as one of the sites said 4.4 lbs shipping weight.

Is that really what new chains cost? How hit or miss is a used chain?

From what I've read on R3V, I thought that the chains almost never wore out, but stripping the splines was more common, BUT cases of chain wear are more common if the T-case oil is low. I've heard through word of mouth that the chains wear out commonly also.

[spdracrm3]

i saved this link after someone posted it ,never used them but they do have a listing ,might be worth a call, i know when this was posted a few years ago people were amazed how expensive the chains were then

http://www.drivetrain.com/parts_catalog/transfer_case_replacements_and_parts/transfer_case_chains.html

[nando]

there are two types of chains, they are matched to the sprockets. that's why they want you to buy them as a set, although you don't need to. you just need to make sure you get the right chain.

also, the chains are not being made anymore by BW. I know the guy who bought them all up, apparently he uses them in the rear diff of a Plymouth Prowler to build shorter ratio diffs. He and I talked about it for a while, trying to find alternatives. there aren't really any good ones. Best we could do is get two smaller chains which is what they do now anyway (and why you can't get wider chains anymore). they still make the links, the issue is the longer pins that hold them together.

BMW has chains available but they are $900. if that drivetrain.com place does indeed have a replica chain it's probably worth investigating.

[Nisse Järnet]

Check with ZF directly, i got a price quote for a brand new E34ix TC chain a couple months ago. It was around ~450$
A factory rebuilt TC was around 3000$ btw :D

[nando]

ZF didn't make the E30 chain, borg warner did. :)

[The Dark Side of Will]

i saved this link after someone posted it ,never used them but they do have a listing ,might be worth a call, i know when this was posted a few years ago people were amazed how expensive the chains were then

http://www.drivetrain.com/parts_cata...se_chains.html

Awesome! Thanks!

[The Dark Side of Will]

ZF didn't make the E30 chain, borg warner did. :)

Did the Prowler guy but up BMW's stock, ZF's or BW's? (Or all of them?)

We tried to cross-reference BMW's part number on ZF's web catalog, but nothing came up.

[Nisse Järnet]

ZF didn't make the E30 chain, borg warner did. :)

Aha, shit :)

Did the Prowler guy but up BMW's stock, ZF's or BW's? (Or all of them?)

We tried to cross-reference BMW's part number on ZF's web catalog, but nothing came up.

You have to contact ZF, the numbers aint the same.

[nando]

AFAIK ZF doesn't sell the chain. they might have some but you can't purchase them without a rebuilt transfercase.

the Prowler guy bought them all from BW and whatever NOS he could find. He was pretty sure he bought all the remaining new chains other than what BMW has. I sold him 2 of my used chains since he couldn't find new ones. we discussed options like replacing the 1 1/2" chain with two 5/8" chains, but that would require modified or custom sprockets.

in any case, even if ZF and BMW have some, they aren't being produced anymore by BW. they only make narrow chains now, because 2x smaller chains are just as strong as 1 wider chain, but they're quieter and more efficient. I think the longest pins you can get are maybe 1" long. If we could get sufficient length pins, they could be remade as they still make the links.

[iXerces]

Has there been a discussion about using a 3D printing approach to replace such NLA items as the pins nando is talking about?

Full disclosure, I know practically nothing about 3D printing nor machining, but from what I understand this might technically be feasible if you could get an accurate copy made. You'd probably have to have the actual metal work/machining being done by some large outfit that specializes in metal 3D printing since in home units only do plastic, AFAIK. What are the other major potential barriers? Maybe it would be cost prohibitive either way, for the moment at least...

Thoughts?

[AndrewBird]

3D printing is only really intended for prototype parts and no machine that exists today can make full strength parts.

The issue I see with the pins is they are more of a rivet than a pin. You would need to figure out how to peen the end and get the correct tension once assembled, which could take some trial and error.

Seems much easier to me to modify the sprockets to run two chains. All you would need to do is turn a groove in the center of each sprocket for the ends of the chain to sit in.

[nando]

The pins are what take all the drivetrain forces. You can't make them with a 3d printer, they are made from steel wire of a specific grade.

[nando]

3D printing is only really intended for prototype parts and no machine that exists today can make full strength parts.

The issue I see with the pins is they are more of a rivet than a pin. You would need to figure out how to peen the end and get the correct tension once assembled, which could take some trial and error.

Seems much easier to me to modify the sprockets to run two chains. All you would need to do is turn a groove in the center of each sprocket for the ends of the chain to sit in.

I think this is possible but the sprockets are hardened which makes machining more difficult. There was a specific chain used in a snowmobile that he thought would work, I'll see if i can dig up the part number.

[Nisse Järnet]

Koenigsegg 3D prints turbo housings etc so it can be done but its expensive :)

https://www.youtube.com/watch?v=DNedUZxP8NU

[nando]

this isn't a turbo housing, it's a hardened steel wire. :p