Transfer case interchange lwx500 to atc500
 

03 4.6is transfer case female splines to front driveshaft are worn. the tcase parts arent available to repair the output. I sourced a front drive shaft extension repair but its fit is loose and not ideal on the lwx500. the tcase chain isnt available for the lwx500 or nv125 either. Id like to swap in the atc500 as it was also avialable on the e53. I was planning on using a simple on/off switch to engage the transfer case motor to switch between rwd and 4wd. Anyone done this before?

Did you check with Cobra Transmissions? I did a full t-case rebuild last year and bought everything from them as a kit. I also bought a new front output shaft from them as well.

He did say parts were getting scarce though, so he may be out of stock by now too.

As far as the ATC500, Im subscribed! Would like to see it done.

ive checked many different vendors including cobra. They have all the parts for the atc500. Very few for the nv and none for the lwx. No one has a chain either and one vendor mentioned he might have one in june but not going to hold my breath. Im going to confirm that (i hope) the 5hp24 only had one output shaft version which if thats correct means the coupler shaft between the trans output and tcase input should be able to work with my trans. not sure if the tcase will come with this coupler but i would hope so lol.

Interesting. I have the LWX and rebuilt it back in the fall of 2024, if I recall correctly. Glad I did now that you tell me the parts are non-existent.

I actually bought an eBay donor and rebuilt that one as the X5 was my daily until recently. I have the OE LWX in my storage shed and was thinking of rebuilding that one too, amd selling it. Looks like it’s scrap now.

The mounts must be identical on the ATC500, hopefully? They didn’t change that with the facelift, right?

If so I would assume it can be installed. The only other showstopper may be the input shaft from the transmission as I imagine any other differences can be overcome by swapping parts that should be available (driveshafts?). The NV and LWX had different inputs (from the 5hp24) so there’s a chance the ATC input may be different as well. Cobra sold an input shaft for the NV that would allow it to be swapped in for an LWX.

My assumption is that since the 5hp wasn’t different between cars with different transfer cases, any input differences between transfer cases has to do with the length of the input shaft. If this is true, then I’m sure a too-long input shaft can be cleanly cut down to length by a machine shop and installed into the ATC case. I wonder if the cobra people would be willing to tell you of the input shafts are different, and if so, how? I. Sure if you were buying a rebuild kit they would.

i talked with the owner of erikkson industries who specialize in the 5hp24 and is a great wealth of knowledge and assistance. He thinks that the splined output shaft is the same on all bmw x5 5hp24. Which means as long as whatever tcase you use has the coupling sleeve then your g2g. I talked with another specialist from tcbmwx5.com (good resource) and he said my idea of actuating the motor in the atc tcase would not work as there is more involved then a simple on off function. So the nv case should bolt right in.
However
The whole reason to use a new tcase was to simply have the front drive output flange be new and matched to a new extended length driveshaft for best durability. My front flange is typically worn in the lwx tcase though still engages the also worn front shaft tightly and with no play in the radial/rotating back and forth direction. I ordered a 65$ shaft extension on ebay advertised to fit only the nv tcase but was pretty sure it would work with the lwx front flange. It works but the fit around the splines radially has play/is loose and would surely make a clunk. So i talk to tcbmwx5 and he says that the aftermarket extended drive shafts are loose like that. so theres really no point in going with a new case and shaft. My original tcase other then the worn front flange and stretched chain (which i finally found) is fine. My only other idea to actualy fix the front drive spline issue without creating another problem is to see if a higher quality shaft extension from germany / austria has a spline interface closer to oe.

I can’t recall which eBay spline extension I bought when I extended my front driveshaft, but it fit like a glove in my LWX. I’ll see if I made any notes when I get back home in a few days.

Yes, there was only one adapter shaft used for all the 5HP24 E53 transmissions (BMW p/n 24 20 1 423 756, ZF p/n 1058 314 025). The same part was fitted to both the 4.4i transmission (1058 000 029) and the 4.6iS transmission (1058 000 034)

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Phil

RRPhil, seeing your reply reminded me that several years ago you were wondering how the 4.4 version of the 5HP I am using with the 4.6 motor that I swapped into my x5 would hold up.

I’ve got around 25k on the combo at this point and I’m happy to report that I haven’t ruined it yet. I don’t regularly stomp on it, but occasionally I open it up. It also gets lots of light off road and unimproved road use. I keep an eye on the temps periodically as I figure this will be where I’ll notice any impending problems.

Great to hear that your 4.4 transmission is still performing fine in your 4.6

I think we probably identified the D-brake (used in 3rd & 5th gears) as the highest risk item (the 4.4 has 4 clutch plates and the 4.6 has 5). Maybe the characteristic of the 4.4 torque converter helps. I guess the solenoids may also adapt, too, to offset any clutch slip.

As you say, the 260mm converter is more likely to overheat the fluid, as that engine was matched to the 280mm unit.

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Phil

Thanks RRPhil. I was thinking about swapping the TQ out, but realized (and your pic confirms) that the bell housings are different. No ribs on the 4.6 version.

I may have a line on a 4.6 bell housing. Would it do any harm to swap in the bell housing and larger TQ if I ever need a new one?