diff swap

redrum36 · 08-24-2011, 06:15 PM

is there any reason that a diff from a manual and from an automatuic cannot be swapped? are they both the same gears too?
thanks
d

cpt97m3 · 08-24-2011, 07:46 PM

Quote:

Originally Posted by redrum36

is there any reason that a diff from a manual and from an automatuic cannot be swapped? are they both the same gears too?
thanks
d

6MT are 3.08 and Auto's are 3.46. I believe the cases are different also, at least on the later models.

redrum36 · 08-24-2011, 09:26 PM

I would love to go 3.46. I believe that they are swappable but just need to confirm 100%.

TX78666 · 08-24-2011, 09:56 PM

I believe you are right. I did this swap on my e46. Planning to do it on my 135. It looks like a lot of non 1-series diffs ought to fit as well.

TX78666 · 08-24-2011, 09:59 PM

The fitment guide for this diff (and others, I am sure) seems to indicate there are lots of options.

http://parts.bmwofsouthatlanta.com/p...107571187.html

TX78666 · 08-24-2011, 10:04 PM

3.46 diff.

http://parts.bmwofsouthatlanta.com/p...107572055.html

Looks like a lot of 3-series diffs will work. Should be a fairly easy find. Might need to swap flanges.

redrum36 · 08-24-2011, 10:16 PM

cool! now to find an LSD!

nordique14 · 08-25-2011, 10:19 PM

Quote:

Originally Posted by cpt97m3

6MT are 3.08 and Auto's are 3.46. I believe the cases are different also, at least on the later models.

my diff builder told me that the 128/328 and the later build (9/07) 135/335 automatics use a smaller 188L case. The 135/335 manuals use a 215L case. So you cannot simply swap auto for manual or even 128 manual for 135 manual.

BerkTechnology · 08-26-2011, 01:27 AM

Quote:

Originally Posted by nordique14

my diff builder told me that the 128/328 and the later build (9/07) 135/335 automatics use a smaller 188L case. The 135/335 manuals use a 215L case. So you cannot simply swap auto for manual or even 128 manual for 135 manual.

You can swap the entire diffs over from any 135/335/auto/manual. The ring gear size does not matter. The 188 & 215 refer to the PCD of the ring gear. While the cases are physically different sizes they both bolt up exactly the same to the driveshaft and axles.

128/328 diffs are an entirely different animal as far as the case goes. Driveshaft for sure won't bolt up, not sure about the axles though, never tired.

So if you find yourself a 188 case you should be okay to use that as your core for a diff build. OS Giken makes diffs for both sizes.

nordique14 · 08-26-2011, 11:02 PM

Quote:

Originally Posted by BerkTechnology

You can swap the entire diffs over from any 135/335/auto/manual. The ring gear size does not matter. The 188 & 215 refer to the PCD of the ring gear. While the cases are physically different sizes they both bolt up exactly the same to the driveshaft and axles.

128/328 diffs are an entirely different animal as far as the case goes. Driveshaft for sure won't bolt up, not sure about the axles though, never tired.

So if you find yourself a 188 case you should be okay to use that as your core for a diff build. OS Giken makes diffs for both sizes.

Thanks for the clarification. I assumed the the different cases meant the output flanges would be in the wrong location preventing any direct swap.

BerkTechnology · 08-27-2011, 01:55 PM

No problem!

08-24-2011, 06:15 PM	#1
redrum36 135i-DIOT 11 Rep 124 Posts Drives: 2011 135i Join Date: Apr 2011 Location: chicago iTrader: (1)	diff swap is there any reason that a diff from a manual and from an automatuic cannot be swapped? are they both the same gears too? thanks d __________________ 2011 135i -muffler delete, AFE intake, springs, sway, vorslag, Stoptech STR60 david@shark3.com "Faster, Faster, until the thrill of speed overcomes the fear of death."Hunter S. Thompson FS:VISHNU Procede
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08-24-2011, 09:26 PM	#3
redrum36 135i-DIOT 11 Rep 124 Posts Drives: 2011 135i Join Date: Apr 2011 Location: chicago iTrader: (1)	I would love to go 3.46. I believe that they are swappable but just need to confirm 100%. __________________ 2011 135i -muffler delete, AFE intake, springs, sway, vorslag, Stoptech STR60 david@shark3.com "Faster, Faster, until the thrill of speed overcomes the fear of death."Hunter S. Thompson FS:VISHNU Procede
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08-24-2011, 09:56 PM	#4
TX78666 Lieutenant 7 Rep 443 Posts Drives: e46 330i ZHP, N55 135i Join Date: Jul 2011 Location: 78666 iTrader: (0)	I believe you are right. I did this swap on my e46. Planning to do it on my 135. It looks like a lot of non 1-series diffs ought to fit as well. __________________ Because... grocery getter.
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08-24-2011, 09:59 PM	#5
TX78666 Lieutenant 7 Rep 443 Posts Drives: e46 330i ZHP, N55 135i Join Date: Jul 2011 Location: 78666 iTrader: (0)	The fitment guide for this diff (and others, I am sure) seems to indicate there are lots of options. http://parts.bmwofsouthatlanta.com/p...107571187.html __________________ Because... grocery getter.
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08-24-2011, 10:04 PM	#6
TX78666 Lieutenant 7 Rep 443 Posts Drives: e46 330i ZHP, N55 135i Join Date: Jul 2011 Location: 78666 iTrader: (0)	3.46 diff. http://parts.bmwofsouthatlanta.com/p...107572055.html Looks like a lot of 3-series diffs will work. Should be a fairly easy find. Might need to swap flanges. __________________ Because... grocery getter.
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08-24-2011, 10:16 PM	#7
redrum36 135i-DIOT 11 Rep 124 Posts Drives: 2011 135i Join Date: Apr 2011 Location: chicago iTrader: (1)	cool! now to find an LSD! __________________ 2011 135i -muffler delete, AFE intake, springs, sway, vorslag, Stoptech STR60 david@shark3.com "Faster, Faster, until the thrill of speed overcomes the fear of death."Hunter S. Thompson FS:VISHNU Procede
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08-27-2011, 01:55 PM	#11
BerkTechnology Lieutenant Colonel 223 Rep 1,565 Posts Drives: Fast Join Date: May 2008 Location: Irvine, CA iTrader: (1)	No problem!
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