[toicy4ya]

Sup Guys,

Anyone know what are the signs of a bad transfer case mount? Anyone ever replace one?

I noticed when driving and coming to a quick stop my car makes a certain "kaplunk" sound. It feels like a bad motor mount, but they checked out fine.

[floydarogers]

The transfer case doesn't have a mount per se - it's attached/mounted to the back of the transmission, which is supported by the rear engine/transmission mount.

You should check the play in the center driveshaft support, the guibo, the rear u-joint, etc.

[toicy4ya]

Is there any way to tell if it's bad while driving?

[xthejuicex]

Originally Posted by toicy4ya

Is there any way to tell if it's bad while driving?

Mount a GoPro or another action camera to the transfer case cross member and see if you can see anything with significant play or movement.

[PhaseP]

Originally Posted by floydarogers

The transfer case doesn't have a mount per se - it's attached/mounted to the back of the transmission, which is supported by the rear engine/transmission mount.

You should check the play in the center driveshaft support, the guibo, the rear u-joint, etc.

Transfer case has a mount. On xi (xdrive) the mounts are the two engine mounts on engine and then the transfer case mount. On xi transmission itself has no mount since transfer case has it.

330xi:
http://www.realoem.com/bmw/enUS/part...MW-330xi&mg=22

330i :
http://www.realoem.com/bmw/enUS/part...BMW-330i&mg=22

If car is lifted it can be diagnosed for extra play with a pry bar and visual inspection.

[tetsuo111]

I just bought new motor mounts (034 Motorsports solid rubber 50A) and a new OEM transfer case mount, as preventative maintenance at 55k miles.

The transmission / transfer case bushing should be upgraded at the same time as the motor mounts, but in our case (xDrive), there are no aftermarket, low-compliance bushings available. I plan to fill the voids in the stock TC bushing (45A with large voids to minimize NVH) with 65A poly fill (3M Window Weld) to reduce the compliance, resulting in a firmer drivetrain.

Will update in a separate post for results.

[mikes4]

Originally Posted by tetsuo111

I just bought new motor mounts (034 Motorsports solid rubber 50A) and a new OEM transfer case mount, as preventative maintenance at 55k miles.

The transmission / transfer case bushing should be upgraded at the same time as the motor mounts, but in our case (xDrive), there are no aftermarket, low-compliance bushings available. I plan to fill the voids in the stock TC bushing (45A with large voids to minimize NVH) with 65A poly fill (3M Window Weld) to reduce the compliance, resulting in a firmer drivetrain.

Will update in a separate post for results.

Someone has gone this route and I think he said the fill he used was too still and had horrible nvh. Check the xi subforum.

Let me know how yours turns out. I've been toying with the idea of making mounts for xi people by creating a cast of the existing mount and then doing a new mount with harder durometer rubber with the metal insert jigged to the correct position, but I have more good ideas than I do spare time lately.

[tetsuo111]

Originally Posted by mikes4

Someone has gone this route and I think he said the fill he used was too still and had horrible nvh. Check the xi subforum.

Let me know how yours turns out. I've been toying with the idea of making mounts for xi people by creating a cast of the existing mount and then doing a new mount with harder durometer rubber with the metal insert jigged to the correct position, but I have more good ideas than I do spare time lately.

Mike, I don't spend enough time in the xDrive forum as I ought to. Thanks for this.

My understanding is that of the entire drivetrain, the transmission / transfer case bushings have the greatest potential for NVH. I've removed compliance throughout my suspension, including solid RSBs, without any negatives on NVH. The Turner Delrin diff bushings are the only low-compliance mod that resulted in an audible and somewhat distracting "whining" sound. I actually enjoy it, but most of my passengers don't.

I'll search for that reference. I'm not surprised someone has tried this, although I thought I might be first. I might find a happy compromise by only partialling filling those voids, say 1/2 or 3/4 full. I plan to use 3M Window Weld as the poly filling. The stiffness spec is 65A, compared with OEM = 45A, and BMW Group N rubber at 70A rubber. The numbers seem "reasonable" but only a test will reveal success or failure.

[Julian2485]

Originally Posted by tetsuo111

Mike, I don't spend enough time in the xDrive forum as I ought to. Thanks for this.

My understanding is that of the entire drivetrain, the transmission / transfer case bushings have the greatest potential for NVH. I've removed compliance throughout my suspension, including solid RSBs, without any negatives on NVH. The Turner Delrin diff bushings are the only low-compliance mod that resulted in an audible and somewhat distracting "whining" sound. I actually enjoy it, but most of my passengers don't.

I'll search for that reference. I'm not surprised someone has tried this, although I thought I might be first. I might find a happy compromise by only partialling filling those voids, say 1/2 or 3/4 full. I plan to use 3M Window Weld as the poly filling. The stiffness spec is 65A, compared with OEM = 45A, and BMW Group N rubber at 70A rubber. The numbers seem "reasonable" but only a test will reveal success or failure.

Yes someone did try it and said the nvh was to much for him

[Supermoon]

Originally Posted by tetsuo111

Mike, I don't spend enough time in the xDrive forum as I ought to. Thanks for this.

My understanding is that of the entire drivetrain, the transmission / transfer case bushings have the greatest potential for NVH. I've removed compliance throughout my suspension, including solid RSBs, without any negatives on NVH. The Turner Delrin diff bushings are the only low-compliance mod that resulted in an audible and somewhat distracting "whining" sound. I actually enjoy it, but most of my passengers don't.

I'll search for that reference. I'm not surprised someone has tried this, although I thought I might be first. I might find a happy compromise by only partialling filling those voids, say 1/2 or 3/4 full. I plan to use 3M Window Weld as the poly filling. The stiffness spec is 65A, compared with OEM = 45A, and BMW Group N rubber at 70A rubber. The numbers seem "reasonable" but only a test will reveal success or failure.

Did you end up doing this?

[Rotorocious]

Thanks for bumping this. I was thinking of replacing the OEM mount or doing that fill idea.
Has anyone done that too? I bet it doesn't just pop out easily.

[Supermoon]

I ordered a cartridge of 3M windshield adhesive.
50-55A hardness.
A notch softer than the window weld so hopefully it will cause less NVH.

[tetsuo111]

Originally Posted by Supermoon

Did you end up doing this?

I fabricated low-compliance (60A durometer) mounts using new, OEM bushings and a poly vacuum kit with Energy Suspension poly material. After re-purposing the kitchen into a lab for an evening, the result was a satisfactory set of new mounts.

Before the mounts were installed, my car was hit and totalled.

My current daily is an E91 6MT RWD. The drivetrain was treated with new E30 trans mounts (thanks for the tip, feuer !), 034 Motorosports N54 engine mounts, Turner Al billet RSBs, and Turner Delrin diff mounts.

The drivetrain is quicker to spool-up after reducing compliance. The sole bump in NVH results from the Delrin diff mounts. The NVH is less (subtly) with Delrin bushings, compared with the solid Al billet diff bushings on the old car.

Shameless promotion - the 60A bushings are available. PM.

[Julian2485]

Originally Posted by Supermoon

I ordered a cartridge of 3M windshield adhesive.
50-55A hardness.
A notch softer than the window weld so hopefully it will cause less NVH.

Please keep us posted

[PhaseP]

Originally Posted by Rotorocious

Thanks for bumping this. I was thinking of replacing the OEM mount or doing that fill idea.
Has anyone done that too? I bet it doesn't just pop out easily.

No it doesn't pop out easily (no surprise )
I had replaced my transfer case mount a few mounts ago. I had taken pictures, could write a DIY sometime if I get to it.
I bought a special tool for BMW transfer case mounts. Without it would be very difficult, unless you can fabricate similar tool yourself. Even with it I had to do some improvising.
The old mount wasn't really bad when I took it out. It had just started cracking but very early stage. I had a slight clunk at sudden movements, was thinking the cause was this mount, noticing the cracks in the rubber. But after removing it and being able to inspect close up, it was fine, could go a few years more. My clunk is still there with new one installed. It is slight though, someone driving with me cannot notice it. But I can.

[Julian2485]

I just emailed strongflex to see if they can make a poly bushing for us xi Guys

[Julian2485]

Good news guys strongflex said they decided to make poly inserts for us xi guys but also stated it will take a little time since they have other project going on

[Supermoon]

Replacing this mount seems like a huge PITA without a proper tool.
The one I found cost over $200. I'm out.

[Rotorocious]

Originally Posted by Supermoon

Replacing this mount seems like a huge PITA without a proper tool.
The one I found cost over $200. I'm out.

Ya ,it really isn't an issue now but I'd be in that area anyway doing maintenance . Maybe I'll wait for the poly mount insert or squirt in window adhesive lol.