Can you fit a 335i diff onto a 135i? (different input flanges issue)

[Lewis Cosgrove]

Right I'm looking to replace the diff on my 135i, Iv been searching around for a good used one and found one of Ebay with the correct part number. However it was removed from a 335i not a 135i and it seems to have a different input flange than the one found on a 135i diff... Just wondering if anyone could tell me if i would be able to take the 3 bolt flange off my broken 135i diff and fit it onto the new 335i one. The 3 bolt flange on the 135i seems to be held on by the large nut in the center, which should be easy to remove and then slide off the flange piece. But given that there is a spline with no threads on it coming out of the 335i diff it would be impossible to fit it on. Its looking like I'm going to need to find a used 135i diff which wont be easy

335i Diff:

https://3a663eb0fef48c6d2d60-a88f8eb...30869_x800.jpg

135i Diff:

http://aswr-partsimages.s3.amazonaws...c751e0337b.jpg

[ShocknAwe]

As long as the pumpkin is the same size and you swap in the same ratio (auto=3.46, 6mt=3.08), it'll fit and function identically.

[Lewis Cosgrove]

Its a manual so the 3.08 ratio. Its the same size diff same ratio its just it connects to the driveshaft differently which is a problem. You can see the difference in the pictures above just wondering if its possible to swap the 135i 3 bolt flange onto the 335i diff.

[dtla1]

I'm not sure where you got the image for the 135i differential, but I think it's wrong. Maybe for a different generation, but e-chassis 135 and 335 parts are pretty much interchangeable.

[Lewis Cosgrove]

No I've looked at the one on my car and its the 3 bolt flange and when you look them up they all have the 3 bolt flange as well. Its strange, why couldn't it just be the same as the 335i.

[Jorgensen54]

It would make absolutely no sense for that 3bolt flange to be threaded. Torque would spin it right off and you'd get no power transfer.

It looks like you'd take the pinion nut and cardan shaft nut(joint) off the 3er diff, and replace with the 3-bolt flange... but that splined section of the pinion shaft protrudes much further on the 1er diff. At least in the pictures.

[juld0zer]

It won't work. They are not interchangeable unless you get the matching rear section of the prop shaft but you'd then need to rebalance the whole shaft assembly which adds cost and downtime.

The reason is if you have a bolted diff (aka 3 bolt flange), the rear section of the prop shaft has a centring bush that slips onto that skinny protrusion. So even if you can transplant the 3 bolt flange across to the inserted diff (aka 50mm big tight nut), you have the risk of vibration. I have a feeling the flange will fit fine, because the large bi-hex nut on the inserted diff is the locknut and 'flange' in one. The other problem you have is setting the pre-load with your transplanted flange.

My suggestion is to verify which type of diff you have, then go shopping. It can't be that hard to find a suitable donor. After all, you guys in the states have an abundance of wrecking yards and a lot more BMWs than us here in Australia!

[Lewis Cosgrove]

Thank juld0zer for the info, yeah think I'm going to have to wait and try to find a used 135i diff somewhere. Only issue is I live in the UK and I've only ever seen one other 135i in the last year here, I might be waiting a while haha

[Gizmo135i]

I’m not 100% sure this applies to all 135 cars but I’m pretty sure most have the flange nut like in the picture of the 335i diff. Bmw hasn’t used a 3 bolt flange/flex disk on the rear joint of the driveshaft for some years.

I would check your car again, if you google 135i diff all of them have the sunk flange nut type joint.

[Traf]

I have a 135i and it is a guibo type coupling at the rear. Luckily for me because it is beefier than the nut type.

[vtl]

I beleive US spec 135i models all had the insert nut style propshaft. Mine is an australian model (Euro RHD spec basically) and had the 3 bolt flange. Have since swapped it for a M3 diff though.

[juld0zer]

It might be specific to the transmission perhaps?

[vtl]

Originally Posted by juld0zer

It might be specific to the transmission perhaps?

The 3 bolt flange is only found on certain euro spec manual 135is, and not all of them. I have a 2008 and my friend has a 2009 135i manual which also has the 3 bolt flange. All 335is have the insert nut propshaft

I've seen a 135i (early 2008) manual with the insert nut and a later 2013 135i n55 has the insert nut as well.

The 3 bolt flange should be stronger than the small CV joint you get with the insert nut coupling. Good if you do lots of drag launches on drag radials.

[frontside0815]

Had exactly the same question.
Wrote Mfactory and they told me the same like juld0zer: it wont work :-(.

What i still would like to know: If you have a 3.08 LSD would you be able to use the Diff with the ring gear in the E82 pumpkin?
Of course you have to reset the backslash, but it would still be easier then machining of the welded ring gear...

It is so fucked to get a LSD into our cars.

Concerning the 3 bolt flange: I have a german 2009 135i and i have the 3 bolt flange with two Flex discs!

[juld0zer]

Assuming both diffs are the same physical size, then yes I don't see why the guts would not be interchangeable.

But.. The effort may equal getting your welded diff sorted out.
Don't some companies sell exchange diffs with LSD already installed? That significantly reduces the downtime and mucking around with bearings, setting the preload, seals etc.

[Gizmo135i]

Originally Posted by frontside0815

Had exactly the same question.
Wrote Mfactory and they told me the same like juld0zer: it wont work :-(.

What i still would like to know: If you have a 3.08 LSD would you be able to use the Diff with the ring gear in the E82 pumpkin?
Of course you have to reset the backslash, but it would still be easier then machining of the welded ring gear...

It is so fucked to get a LSD into our cars.

Concerning the 3 bolt flange: I have a german 2009 135i and i have the 3 bolt flange with two Flex discs!

I guess that would explain why I’ve never seen one here in the u.s. with a 3 bolt flange lol.

If you already have a diff with lsd and it bolts in then why not just get a 135i driveshaft with the cv joint from a junk yard?

[Traf]

There is no 135i shaft with a CV joint. The CV joint driveshaft is M3 and 1M only.
I do have a manual diff with it's 3 flange drivershaft if anybody in europe is interested, not using them anymore since i switched to M3 diff.

[vtl]

Originally Posted by Traf

There is no 135i shaft with a CV joint. The CV joint driveshaft is M3 and 1M only.
I do have a manual diff with it's 3 flange drivershaft if anybody in europe is interested, not using them anymore since i switched to M3 diff.

No the insert nut propshaft on most x35is is actually a small CV joint. It allows smooth articulation and has negligible 'wind up' but is very small.

The V8 CV joint is found on a lot of older V8 BMWs and M cars (1M and M3 included). This is a more traditional style CV joint and is much larger than the insert nut propshaft