[cookiemontis]

I wanted to shared some details on performing a Manual Transmission Swap for others since there not a ton of information documenting this on the E-Series platform. For E and F series equipped with an N55 the factory manual transmission GS6-45BZ is known to contain weak second gear synchros. This seems to be the consensus after scouring the forums across various platforms equipped with the GS6-45BZ (Non M variant).This however does not seem to be the case for M Variants ( M2, M3, M4 ) which have not exhibited the same issues.
However I am not sure for platforms equipped with the B58 engine or early M2 w/N55.

Since BMW does not service manual transmissions sourcing internal components seems just about impossible and your only recourse is a full replacement by either locating a second hand or purchasing new. Based on my research the GS6-53BZ Manual transmission was equipped with all N54 equipped vehicles is much stronger ( as well as 20lbs heavier ).

The GS6-53BZ is also slightly longer than the GS6-45BZ as well as having the pilot bearing located in the transmission input shaft rather than the flywheel. This requires at minimum getting the proper selector rod, shifting arm and 6-bolt N54 flywheel with the pilot shaft in the flywheel.

I have a 2013 E-92 Coupe with a factory Manual transmission and had already upgraded my clutch to 335is/550 as well as switching over to an Mfactory Single Mass Flywheel. I purchased a GS6-53BZ second hand off Ebay from a 2009 335i which included the shifting arm and selector rod and was able to convert my flywheel by pressing out the pilot bearing and pressing in the Mfactory Pilot shaft it includes when purchasing new.

I also was able to reuse my N55 Factory Manual Driveshaft even though it is longer (L=1485MM :: 26107614408) and there was a 1.5-2.0 inch available space between the front/rear shaft which would have equated to 2.0-2.5 inches if I had used the N54 Driveshaft.

I believe BMW used a slightly shorter Driveshaft on the N54 Manual transmissions (PROPSHAFT L=1470MM :: 26107614384) too allow you to drop the front shaft from the Guibo without loosening the Center support bearing which was required when I reused my N55 Factory Manual Driveshaft.

To perform the swap you will need to source the following:
New or Used from Donor vehicle ( This includes pre-lci 335i, 135i, 535i and all 335is models factory equipped with N54. )

01 Dual-Mass Flywheel (illustration is incorrect and should show pilot shaft in flywheel ) :: 21207590942
https://www.realoem.com/bmw/enUS/sho...diagId=11_3187

Or if you elect a MFactory Single Mass Flywheel which contains both ( N54 Pilot shaft and n55 Pilot bearing ) to use with either platform.

11 Selector rod :: 25117524722
01 Shifting arm :: 25117524720
https://www.realoem.com/bmw/enUS/sho...diagId=25_0442

(Possibly)
Manual Driveshaft :: 26107614384 (This is specifically for e9x Series)
Driveshaft to Differential Nut :: M39X1,5X16,5 :: 26117567770 (Will Need to replace if swapping driveshafts)
Please Note, if you are converting from Auto to Manual (using factory Driveshaft/Differential components)
you can use the Auto Driveshaft/Auto Differential(Note-both of these are smaller/weaker than their Manual Trans Counterparts)
you cannot use the Auto Driveshaft/Manual Differential(Center Support will not Bolt Up due to misalignment)
you cannot use the Manual Driveshaft/Auto Differential(Center Support will not Bolt Up due to misalignment)

RECOMMENDED Hardware to replace
FLYWHEEL_BOLTS :: M12X1.5 :: QTY 6 :: 11227520706
PRESSURE_PLATE BOLTS :: M8X18-10.9-ZNS3 :: QTY 6 :: 21207548052
EXHAUST SEALS :: QTY 2 :: 18307553603

TRANSMISSION BELLHOUSING BOLTS
Torx bolt :: M12X50-8.8-ZNS3 :: QTY 2 :: 23001222891 :: 24001218590
Torx bolt :: M12X90 :: QTY 5 :: 23001222894 :: 23000417164
Torx bolt :: M8X50-8.8-ZNS3 :: QTY 3 :: 23001222887 :: 23001220459
Torx bolt :: M10X85-8.8-ZNS3 :: QTY 1 :: 07129903800 :: 07129902652

TRANSMISSION MOUNT
Transmission bearing(mounts) set :: QTY 2 :: 22316799331

TRANSMISSION SEALS ( would recommend if you purchased second hand since transmission is out of vehicle)
Input Shaft seal :: 23127501712
Shifter Shaft seal :: 23121222677
Output Shaft seal :: 23121282458

TRANSMISSION FLUID (Whatever is your preference)

[3pedal335]

One thing to note is there are different bellhousing bolt patterns based on the different code of the gs6-53, sadly I purchased an HGM which has a different bolt pattern and starter location (For v8’s I think). I believe the n54 has the HGX. P.s. if anyone has one I am looking!

[cookiemontis]

That is correct, there is a V8 variant which from photos the right side of the bell housing will be smooth while the I6/N54 variant will have three casting lines going up the bell housing.

Also I would recommend if buying from eBay which is where I got mine, buy from a seller with history selling and more specially shipping items of this size. The first one I bought the seller thought shipping residential in a plastic storage bin was a good idea. Needless to say it did not make it to me in one piece. Took almost 2 weeks contesting it to finally get ebay to refund my money. Provided a picture of the damaged one with the label and three lines on the bell housing.

[sanedo_man]

Originally Posted by 3pedal335

One thing to note is there are different bellhousing bolt patterns based on the different code of the gs6-53, sadly I purchased an HGM which has a different bolt pattern and starter location (For v8’s I think). I believe the n54 has the HGX. P.s. if anyone has one I am looking!

I'm planning out the swap on my 2013 e93 335i Auto. Found a GS6-53BZ but with JGK classification. Will this work with my N55?

[cookiemontis]

The JGX should also work. I am unsure what the differences are with the HGX, but both were used behind the N54.

[moose09876]

Originally Posted by cookiemontis

That is correct, there is a V8 variant which from photos the right side of the bell housing will be smooth while the I6/N54 variant will have three casting lines going up the bell housing.

Also I would recommend if buying from eBay which is where I got mine, buy from a seller with history selling and more specially shipping items of this size. The first one I bought the seller thought shipping residential in a plastic storage bin was a good idea. Needless to say it did not make it to me in one piece. Took almost 2 weeks contesting it to finally get ebay to refund my money. Provided a picture of the damaged one with the label and three lines on the bell housing.

This post just saved me from buying the wrong transmission and wasting a 4 hour drive. Thank you!

[pokemone3215]

Would this work for awd versions? My gs6x45bz 2nd gear syncro is completely gone and I'm considering doing a gs6x53bz conversion.

[simster007]

Originally Posted by pokemone3215

Would this work for awd versions? My gs6x45bz 2nd gear syncro is completely gone and I'm considering doing a gs6x53bz conversion.

I'm in the same situation with a '13 E92 335i xDrive. There are a few detailed posts on RWD swaps, a wild 135i n54 getting the GS6-45BZ swapped (1addicts) and one F30 xdrive swap on reddit (user UnSc_sierra_117). Search "n54 trans swap on n55". He needed
1: shift linkage and bracket extended 19mm.
2: extend the reverse switch harness by 60cm.
3: use an aftermarket clutch and flywheel kit for a 2009-2010 335i.
4: install an n54 short shifter kit to compensate for the longer throws.
5: (optional) install an e9x slave cylinder to delete the cdv.

Now I have yet to confirm anything myself but it appears that the transfer case will adapt between GS6X45BZ and GS6X53BZ. Will need to get the six bolt N54 flywheel due to the change in pilot bearing and appropriate clutch. I was planning on using new N54 dual mass flywheel with 335is/550i clutch as an upgrade. Now supposedly the GS6-45BZ is shorter by about an inch from the GS6-53BZ. Does that occur in the AWD versions? I'm not sure but doubt it will matter much with driveshaft length.

So the GS6X53BZ can clearly mate to the engine, should mate to N55 transfer case even. The one issue I am not sure of is the shifter bracket and linkage may not be long enough and may require the N54 shifter bracket and linkage.

[cookiemontis]

You will most certainly need the shift linkage. I am really unsure if the transfer case interchange. But I am guessing the prop shaft going to the front diff would be different lengths given the n54 transmission is slightly longer. Is the front prop shaft a fixed length?

Also I have the n54 shift linkage, a short throw uuc shifter, the stock n54 shifter and DSS if I recall is the name for both an n54 or n55. I can post some pics if anyone is interested.

I ended up going to a chassis mounted shifter so all that stuff is sitting in a storage bin.

[simster007]

Originally Posted by cookiemontis

You will most certainly need the shift linkage. I am really unsure if the transfer case interchange. But I am guessing the prop shaft going to the front diff would be different lengths given the n54 transmission is slightly longer. Is the front prop shaft a fixed length?

Also I have the n54 shift linkage, a short throw uuc shifter, the stock n54 shifter and DSS if I recall is the name for both an n54 or n55. I can post some pics if anyone is interested.

I ended up going to a chassis mounted shifter so all that stuff is sitting in a storage bin.

Yes, my plan is to use the N54 shift linkage, shift bracket for now which will need some modification.

In regards to compatibility between E92 n54/n55 xDrive 6MT setups... the prop shaft (L=738MM, PN:26209488491), transfer case (27107599693) and rear driveshaft assembly (L=1272mm, PN:26107573485) all match between each which sounds very promising. The difference now lies in the additional length of the GS6X53BZ compared to GS6X45BZ transmissions by ~0.5 inches (about 12–14 mm) overall. Hoping I don't need any driveshaft modifications... Still researching that aspect and if things will bind...

Actually bought a GS6X53BZ already and need to measure the differences. Will update when I can measure them both.

Trying to find a vendor to sell a 6-bolt SMFW with the male pilot shaft installed. Hoping mFactory will suffice and waiting for their email reply. If no luck, I may use the stock N54 DMFW with 335is/550i clutch setup.

[tmontel]

Originally Posted by simster007

Yes, my plan is to use the N54 shift linkage, shift bracket for now which will need some modification.

In regards to compatibility between n54/n55 xDrive 6MT setups... the prop shaft (L=738MM, PN:26209488491), transfer case (27107599693) and rear driveshaft assembly (L=1272mm, PN:26107573485) all match between each which sounds very promising. The difference now lies in the additional length of the GS6X53BZ compared to GS6X45BZ transmissions by ~0.5 inches (about 12–14 mm) overall. Hoping I don't need any driveshaft modifications... Still researching that aspect and if things will bind...

Actually bought a GS6X53BZ already and need to measure the differences. Will update when I can measure them both.

Trying to find a vendor to sell a 6-bolt SMFW with the male pilot shaft installed. Hoping mFactory will suffice and waiting for their email reply. If no luck, I may use the stock N54 DMFW with 335is/550i clutch setup.

So you are in the process of doing this with an x drive? I’ve got the second gear crunch as well. But I found a gs6x53bz code hgy local to me for 1k. With everything included from the pedals, drive shafts, diffs, and everything im nervous to do the swap though. I’ve been reading that I’ll have auto start stop malfunctions which isn’t the end of the world for me. I just hate warning lights. I’d love to know more from you. It seems like if you have the n54 parts it should just all go together aside from the shifter having longer throws, and the 6 bolt flywheel issue? How far are you into it? Have to attempted the install yet?

[simster007]

Originally Posted by tmontel

So you are in the process of doing this with an x drive? I’ve got the second gear crunch as well. But I found a gs6x53bz code hgy local to me for 1k. With everything included from the pedals, drive shafts, diffs, and everything im nervous to do the swap though. I’ve been reading that I’ll have auto start stop malfunctions which isn’t the end of the world for me. I just hate warning lights. I’d love to know more from you. It seems like if you have the n54 parts it should just all go together aside from the shifter having longer throws, and the 6 bolt flywheel issue? How far are you into it? Have to attempted the install yet?

I'm in the planning and buy parts stage. This car was recently purchased and needs a lot of maintenance. Currently not my daily so not in an immediate rush and expecting to perform 6MT swap, seals and oil pan gasket sometime this summer.

Not sure about auto start/stop malfunctions as my car is an E92, not f-chassis. Doing an entire auto to manual swap is definitely more involved and couldn't speak to that. I've seen swap kits online and coding is probably required somewhere.