[bhmax16]

Hey guys, I replaced my front output flange last night because I discovered some wear on it when replacing some bearings in my transfer case last weekend. I figured I'd write up a quick DIY on it for those that are interested. Replacement is simple so I'm going to make this short and sweet.

Tools needed:
Prybar
Rubber mallet
Seal puller

This DIY should be used in conjunction with others in this forum for changing your transfer case fluid and pulling the front driveshaft.

This is what we start with:


After draining your transfer case fluid and removing the front driveshaft, use a prybar and pry on the output flange as shown. A small slide hammer would also work here, but my cv axle puller attachment was too small to fit:


This is the flange removed from the transfer case:


Notice the wear/scouring on the flange:



Use a seal puller to pull out the old seal (or your fingers if you're the hulk):


Here is a shot of one of the bearings I replaced in the transfer case last weekend. BMW does not sell any internal parts for our transfer cases, but you can get the bearings from Cobra Transmission:


Use a seal driver to drive the new seal flush with the transfer case. I like to use a little RTV on the outer edge to ensure a good seal:



Apply anti-seize to the splines of the new flange (BMW provides this with purchase of the flange). Press the flange into the transfer case until you can't push it any further, then slightly rotate to align the splines. Once you are aligned, use a rubber mallet to drive the flange all the way into the transfer case.



Now attach your front driveshaft and fill your transfer case with the proper fluid (it takes about 0.6 quarts). Reattach any plastic shielding under the vehicle that was removed for access.

Go for a spin, or have yourself a cold one of your favorite brew.

[ajaye]

Nice. What lead you to the bearing replacement to begin with, did you have a code(s) or failure? Just curious. Thanks for the DIY.

[bhmax16]

The bearing replacement was due to noise when not under load, especially on the highway. If I was cruising around 70mph, then let off the throttle, I would get a loud rumbling sound. Similar to what you'd experience with a differential with too much backlash, but it was clearly a bearing noise. I diagnosed the front output shaft bearings by grabbing the front driveshaft and wiggling it (I had nearly 1/8 inch of play at the flange). I confirmed these bearings were the issue when I pulled the front driveshaft (effectively making the car rwd and eliminating load from the bearings) and the noise disappeared.

Cobra Transmission is the only source of the bearings to my knowledge. BMW sells no internal parts for our transfer cases, which is asinine. $80 for two bearings and 5 hours of my time and I was back on the road again, vs $2500 for a rebuilt transfer case through BMW. Replacing the bearings was the clear choice.

[ajaye]

Originally Posted by bhmax16

BMW sells no internal parts for our transfer cases, which is asinine.

Unless you are BMW!

Nice work, thanks again for the info.

[ericnk]

how long did the job take you and how did you take it out. did you use a pry bar ?

[E60528xi]

I realize this is an older thread, but I felt it better to resurrect it with additional info that closely applies to this topic than start a new one

First a big thanks to bhmax16 for providing pics and info.

Although I have an E60 528xi, the ATC-300 transfer case is the same as used by the E90 X.

Here's a video that shows the transfer case output shaft;


The output shaft needs clearance to slide in and out (slightly) hence the splines, so some play must be present to allow that movement. Additionally, since the helical gear (that the shaft slides into) sits in the two bearings that bhmax16 described above, any movement of the shaft inside the helical gear is independent of the helical gear bearing play.

However, the total movement felt could be a combination of the two, knowing the normal amount of play associated with the shaft normal clearance would help to compare to what is happening in the video above.

The out put shaft from my vehicle also has some scoring and also has the spline marks similar to bhmax16 (see pics below).

Using a dial caliper I could hardly make out any difference between the worn and unworn surface, maybe less than a .001".

I wonder how much play this would cause?

Does anyone know how much play should there be on a good shaft?


Thanks

[Serqz]

So it's finally snowing here in Iowa a day after I removed my front driveshaft. The input shaft on the front side of the transfer case has some play in it. I removed my driveshaft and the grinding/vibrations went away. I was wondering what you need to pull out the shaft, and if I need to remove the whole transfer case to access it. The pictures you posted aren't available for me anymore, but I was wondering if you still had a few or could guide me in the process. I think there is a 30mm nut holding it on but I might just be able to pry it off. Did you do this project on jack stands?

Thanks for the help,
Nic

[bhmax16]

Originally Posted by Serqz

So it's finally snowing here in Iowa a day after I removed my front driveshaft. The input shaft on the front side of the transfer case has some play in it. I removed my driveshaft and the grinding/vibrations went away. I was wondering what you need to pull out the shaft, and if I need to remove the whole transfer case to access it. The pictures you posted aren't available for me anymore, but I was wondering if you still had a few or could guide me in the process. I think there is a 30mm nut holding it on but I might just be able to pry it off. Did you do this project on jack stands?

Thanks for the help,
Nic

Hey Serqz - I'll have to check my records to see if I still have these photos available somewhere. It appears the location I posted them is no longer active.

There is no nut holding the front output flange on the transfer case that I recall. It should be held in with a clip only (similar to a CV axle shaft). It should pull out of the transfer case quite easily with a bit of coercing using a prybar between the flange and case.

You do not need to remove the transfer case to pull out the front output shaft and yes you can accomplish this on jack stands though I used a set of ramps.

With that said, if you are hearing a grinding sound I fear you may have a bigger issue, such as a bad bearing inside the transfer case. The bearings are generally the source of play which is why I pulled my transfer case to replace them. I only replaced the front output shaft due to scouring, but it was not the source of my play or noise. If you hear a grinding sound you would likely need to drop the transfer case and split the case halves open to assess the damage. I have had luck procuring some of our transfer case bearings from Cobra Transmission. https://cobratransmission.com/BMW-X3...e-Parts-Search The link indicates for X3 or X5 but the parts are still correct. The E90 uses the ATC300 transfer case. The transfer case is not difficult to drop if you need to. I pulled it, replaced the output shaft bearings, sealed the case halves back up and reinstalled in about 5 hours.

[Serqz]

Originally Posted by bhmax16

Hey Serqz - I'll have to check my records to see if I still have these photos available somewhere. It appears the location I posted them is no longer active.

There is no nut holding the front output flange on the transfer case that I recall. It should be held in with a clip only (similar to a CV axle shaft). It should pull out of the transfer case quite easily with a bit of coercing using a prybar between the flange and case.

You do not need to remove the transfer case to pull out the front output shaft and yes you can accomplish this on jack stands though I used a set of ramps.

With that said, if you are hearing a grinding sound I fear you may have a bigger issue, such as a bad bearing inside the transfer case. The bearings are generally the source of play which is why I pulled my transfer case to replace them. I only replaced the front output shaft due to scouring, but it was not the source of my play or noise. If you hear a grinding sound you would likely need to drop the transfer case and split the case halves open to assess the damage. I have had luck procuring some of our transfer case bearings from Cobra Transmission. https://cobratransmission.com/BMW-X3...e-Parts-Search The link indicates for X3 or X5 but the parts are still correct. The E90 uses the ATC300 transfer case. The transfer case is not difficult to drop if you need to. I pulled it, replaced the output shaft bearings, sealed the case halves back up and reinstalled in about 5 hours.

bhmax16 You said you had to replace 2 bearings, which ones were they? I see a few options ranging from $90-230 depending on how many you buy. Did you have to purchase the seal separately?
I have identical symptoms as you but have been driving without the driveshaft in for a few days now with no issues. I’m going to order the bearings tonight and put them in this weekend if they arrive in time. My output shaft has some play but I don’t think I’ll need to replace that. It seems like it is bearing related, no iron stains on transfer case also.
Thanks!

[bhmax16]

Originally Posted by Serqz

bhmax16 You said you had to replace 2 bearings, which ones were they? I see a few options ranging from $90-230 depending on how many you buy. Did you have to purchase the seal separately?
I have identical symptoms as you but have been driving without the driveshaft in for a few days now with no issues. I’m going to order the bearings tonight and put them in this weekend if they arrive in time. My output shaft has some play but I don’t think I’ll need to replace that. It seems like it is bearing related, no iron stains on transfer case also.
Thanks!

Serqz - Absolute minimum you'll need a Qty 2 of these: https://cobratransmission.com/atc-30...ing-55162023-1

You could also just opt for the full bearing kit if you feel like changing them all while you're in there, but if you have isolated the issue to only the front output shaft then no need to swap the other bearings unless it helps you sleep better at night: https://cobratransmission.com/atc-30...kit-55162017-1

Yes I purchased the output shaft seal separately.

Once again I'll remind you that you DO need to drop the transfer case and split the case open to replace the bearings. The output shaft itself can be replaced without removing the transfer case, but if you're doing the bearings you'll need to pull and open the case. You'll need to first remove your exhaust so you can also remove the rear driveshaft.