[kdog_x]

EDIT: Added my rebuild thread here

http://f30.bimmerpost.com/forums/sho....php?t=1426356



Brought my car into the dealer, they advised that they transfer case was broken. They showed me up on the lift how the shaft on the case going to the rear driveshaft was spinning, but the actual flange was not. Then they advised me that it was going to be $5700 to repair

Anyways, got the transfer case removed at home yesterday. Debating whether to purchase a used unit or try to repair this one. So I removed all of the torx head screws from the unit, but I can't figure out how to get the flange removed so I can open the case and inspect. Anyone have any experience with this one?

I removed the snap ring from the shaft, and I don't see any other anything else holding it. I tried giving it some taps with a rubber mallet thinking maybe the shaft came out the back, but it didn't seem like it was budging. Do I need to use some type of puller on the flange? or am I missing something? Thanks!!

[kdog_x]

Got it figured out, just needed a block of wood n a big hammer. Looks like all of the teeth are sheared off on the output flange. Still trying to get the transfer case apart, wondering if just that flange would resolve the issue though

[kdog_x]

Finally got it pried apart and pulled the front case off, thats some serious sealer they use on this thing. Looks like there is a score mark on the output shaft near the bottom (see picture). When I push the flange all the way down past the score mark it turns the whole assembly, but above that the teeth don't engage. (Keep in mind the teeth are pretty worn on the flange.)

Anyone know if that score mark is a sign of damage or if it is normally there? I can get a replacement flange assembly from the dealer for a little over $200, but if the output shaft is damaged, I think I probably need to replace the whole unit since it doesn't appear to be a spare part from what I can tell. I'm hoping that the flange is all that's needed, but the score mark has me wondering. I would hope BMW would use a hard enough material for the shaft itself, that it wouldn't be easily damaged.

[Polo08816]

Originally Posted by kdog_x

Finally got it pried apart and pulled the front case off, thats some serious sealer they use on this thing. Looks like there is a score mark on the output shaft near the bottom (see picture). When I push the flange all the way down past the score mark it turns the whole assembly, but above that the teeth don't engage. (Keep in mind the teeth are pretty worn on the flange.)

Anyone know if that score mark is a sign of damage or if it is normally there? I can get a replacement flange assembly from the dealer for a little over $200, but if the output shaft is damaged, I think I probably need to replace the whole unit since it doesn't appear to be a spare part from what I can tell. I'm hoping that the flange is all that's needed, but the score mark has me wondering. I would hope BMW would use a hard enough material for the shaft itself, that it wouldn't be easily damaged.

Is this transfer case unique to the diesel? Would you be able to point it out via a RealOEM/parts diagram?

[kdog_x]

No, it's not unique to the diesel. It's used in quite a few different models of BMW. 2014+ I think. Its the ATC 35L model

When I flip the Output flange over so that the part with the most teeth is making contact it seems to turn with no issues. So I think the internal shaft is probably good.

I'm going to go ahead and order the output flange some fluid, and replacement driveshaft bolts and I'm gonna give it a try. All of that adds up to about $300, so I can get off at that price I'm def. a happy camper!

[FaRKle!]

Added you to the database.

I think you're the only one to try and take it apart/fix it yourself! Good luck!

[kdog_x]

I'd like to replace the rear output bearing as well, as long as I'm in this deep, since it could be related. But the Atc 35L doesnt seem to have many suppliers for the internal parts. The bearing is about 72mm x 45mm. The older model seems to be 72x35. I'll update if I end up finding a source, got all my other parts ordered

Seems like one of the other models would use the same bearing, but I'm not familiar enough to know. If anyone knows better deinotely fill me in!

[kdog_x]

A couple of updates... I pressed out the rear output bearing the other day. It is a 6009C3 which is a fairly standard deep groove bearing (75mm x 45mm x 16mm) available from several manufacturers. I didn't remove the front shaft bearing since I didn't have issues with the front shaft, but it appears to be a 6208 model bearing dimensions @ 80mm x 40mm. BMW installs them with the numbers facing inwards so you really can't identify them without pressing them out.

The rear output flange is not stocked at any dealer in the United States and is a special order from Germany item. I was told it would take 10 business days to arrive. Luckily I was able to find a parts supplier in the states that had one available (albeit for $70 over the dealer price). So now I'm just waiting on my parts to arrive, but all in all it looks like it should be about a $500 repair

$300 - Output Flange
$100 - Fluid (Got 2 quarts, maybe only needed one?)
$100 - Front / Rear DS bolts / drain plug /rear oil seal / rear bearing

Hopefully everything works out... got my fingers crossed!


I notice I don't see any of my posted pictures on the desktop version of this site? On the mobile app they all show up...

[jdr78569]

DANG! I wish i kept my old one to rebuild. I couldnt find anything on here to rebuild it. Kuddos bro! I had to suffer the told of replacing mine. Sounds like the same thing happened to mine honesly. the rear would free spin but at times would grab and turn the front So probably messed with the teeth.

Hope it all works out! if it does can you post parts and sites so if anyone runs into this they have some info.

[jdr78569]

Originally Posted by kdog_x

A couple of updates...

I notice I don't see any of my posted pictures on the desktop version of this site? On the mobile app they all show up...

Pics show up on my phone app but not the desktop. I had that issue what i did was get on the computer and hit edit, it shows the attachments. I hit show preview and they showed then hit save. It works most of the time but maybe a time or so, if not you can use a 3rd part site and upload them then copy the link. I had to do that for my DIY's I used Imgur.

Man I wish i didnt toss out my xfer case! I know it was possible but never attempted.

[kdog_x]

Hmm, strange. I posted a picture to Imgur and added it above, but that didn't show up either. Also, your other suggestion didn't seem to do it. Not sure what's going on with it

[kdog_x]

If you have time to wait and you know German you can order replacement parts from the manufacturer here:

www.fzth.de

And there's a great exploded view of the transfer case in this PDF on page 25

http://www.fzth.de/fileadmin/user_up...e_2018_web.pdf

[kdog_x]

As you can see from the picture I changed course and decided to do a complete tear down lol. I figure with the cost of the bolts in the fluids it would be silly not to replace all the bearings while I'm in there. If I can put this thing back together successfully when my parts arrive I'll have to do a write up

[jdr78569]

Originally Posted by kdog_x

As you can see from the picture I changed course and decided to do a complete tear down lol. I figure with the cost of the bolts in the fluids it would be silly not to replace all the bearings while I'm in there. If I can put this thing back together successfully when my parts arrive I'll have to do a write up

Makes me want to get a case just incase now lol!Wish i didn't toss mine out, do the AT35L work with all cars are are they vin specific? Great job man! keep it up and let us know! i understand the xfer cases go out commonly on diesels

[kdog_x]

It seems like they go out on alot of models judging from the forums, although most are still within the warranty period. The diesel is lower HP, I would figure that would prolong the life, but there could be some other element I'm missing.

The output flange could be too weak, or the bearing for the rear shaft could have had a bad lot or something. It could be that the "lifetime" fluid needs changing or at least topping off. This has motivated me to change the trans fluid while Its already down, cheap insurance. If the trans goes thats beyond my rebuilding skills.

Got the new flange in! Side by side with the damaged one. Bearings should be in soon!

[FaRKle!]

Originally Posted by kdog_x

It seems like they go out on alot of models judging from the forums, although most are still within the warranty period. The diesel is lower HP, I would figure that would prolong the life, but there could be some other element I'm missing.

I'd imagine it's due more to increased torque from a stop vs gas engines.

[kdog_x]

600 miles (highway) since the rebuild, and its going strong. Changed the tranny fluid while I was in there. There used to be a lag I attributed to turbo lag when taking off, thats almost gone now, much more responsive. I did reset the transfer case and tranny adaptations though. Time will tell how long it lasts. I feel that replacing the input shaft would have been ideal, but it's only available overseas. Requests to Hetzel for the part produced a quote, but once they saw I only wanted one piece... no more communication. I have one on order from a shop in England. They said about 3 weeks. I figure if it goes back out I'll have one ready on the shelf.

[hardparker]

Originally Posted by kdog_x

600 miles (highway) since the rebuild, and its going strong. Changed the tranny fluid while I was in there. There used to be a lag I attributed to turbo lag when taking off, thats almost gone now, much more responsive. I did reset the transfer case and tranny adaptations though. Time will tell how long it lasts. I feel that replacing the input shaft would have been ideal, but it's only available overseas. Requests to Hetzel for the part produced a quote, but once they saw I only wanted one piece... no more communication. I have one on order from a shop in England. They said about 3 weeks. I figure if it goes back out I'll have one ready on the shelf.

You, sir, are awesome! Thanks for all the pics and part numbers.

From what I can tell, it looks like the fit between the output splines and internal splines on the flange is either poor to begin with and worsens over time and that the flange's internal splines are the softer of the two metals in that interface. It would appear that perhaps the circumference of the flange's "tube" where it's splined inside has "belled" out some, further worsening the wear. I wouldn't be surprised if the worn part and new part have different external diameters there. That would probably accelerate the output seal's wear, too.

The flange, in contrast seems in mostly good shape. No discernible wear other than where the end of the flange's splined tube rocked against the output shaft as it wobbled off axis due to the belling and wear of its splines. That's what caused that small groove; the end of the flange's internally splined tube. Perhaps because the flange is a poorer quality cast assembly, versus the forged output shaft, torque over time caused the flange's splined tube to expand in diameter, begin to wobble minutely, and eventually the output shaft's splines simply machined off the softer cast iron's splining inside of the tube.

Solutions to that problem long term would be to metallugically treat a new flange before installation. Either induction hardening or cryo treatment would probably do the piece well. Outside of that, I'd advise packing the splines on the shaft and flange with heavy grease to improve the interface between them.

The clutches seemed to look decent. Did you replace them while you had it apart? I've noticed replacements as I've searched through catalogs for ZF 8HP upgrade parts.

[jdr78569]

Originally Posted by kdog_x

600 miles (highway) since the rebuild, and its going strong. Changed the tranny fluid while I was in there. There used to be a lag I attributed to turbo lag when taking off, thats almost gone now, much more responsive. I did reset the transfer case and tranny adaptations though. Time will tell how long it lasts. I feel that replacing the input shaft would have been ideal, but it's only available overseas. Requests to Hetzel for the part produced a quote, but once they saw I only wanted one piece... no more communication. I have one on order from a shop in England. They said about 3 weeks. I figure if it goes back out I'll have one ready on the shelf.

Awesome man! im definitely going to keep a look out for another case and get parts ready. Im not getting rid of my F31, especially since its paid off lol. So need to be prepared for the worse. It sucked when it went out the 1st time. Little time and limited resources = lots of money. In total what did all the parts go for and time? Any parts u didn't rebuild that u recommend?

[kdog_x]

I didn't replace the clutches. They seemed to be in great shape so I reused them. I'd need to add up the exact cost but it was about $500, with $275 being spent on the flange. The flange could be gotten from Germany a bit cheaper with enough time, if your car isn't down waiting for it. If I could have gotten the input shaft I would have replaced it as well... that would add about $200 to the bill according to what I've been quoted. That would put a total rebuild of all of the bearings, input shaft, output flange, fluid, and driveshaft bolts at about $700 or so, certainly a bit of labor involved, but not bad for an essentially new unit. Obviously if something else was bad on your transfer case, your parts needs may vary.

I'm putting a new thread together with my rebuild details and photos. It does require a few specialty tools, but isn't overly difficult if you have access to a press and some bearing splitters or a local shop that will work with you.

http://f30.bimmerpost.com/forums/sho....php?t=1426356

[catskillclimber]

Did you find the missing teeth or were they pulverized?

[kdog_x]

Originally Posted by catskillclimber

Did you find the missing teeth or were they pulverized?

Didn't find any missing teeth, but there were shavings visible once the output flange was removed.

I don't know what's going on with the other post, I uploaded all of my pictures to imgbb last night, but it wont pull up the album for me to get to the links, it just sticks me on the upload page and no other options work. Maybe they're doing site maintenance or something.