Is it possble to use the GS6-53BZ (n54 trans) on a N55?

[cficare68]

Ive been searching for the better part of a week now and can not get a direct answer to this question. Long story I lost 1st gear in my transmission on my 2011 135i. The car will go into gear and start to move forward but will throw it out of gear. 2nd threw 6th and reverse works great. Which leads me to believe ive damaged a bearing internally or chipped a tooth off of first.

My first option was to have it rebuilt but upon researching it appears that bmw has decided to be greedy and not sale the internals to these trans. Which has left me with two options. Option A. A used trans which will run me 2000 to 2900 dollars. Or option B a new trans from BMW for around 3600.

So im now left wondering if i were to get a n54 trans (which is more than half the price of a n55 trans with more availability) would it work. From what i have read the belt housing should bolt up with out an issue cause on the 4 cylinder and 6 cylinder motors bmw has been using the same bellhousing since the 70s. Also with the 1m using a n54 motor and a n55 trans i would assume the input shafts would be the correct spline count as well.

Does anyone know if in fact if it would be a direct fit? Cause i can seem to find a direct answer. Just bits and pieces that there is a possibilty of it working.

Thanks in advance.

[juld0zer]

Possible to mock up a paper template of your bell housing, going to the shop with the donors and checking the fitment?

[rich_mane]

Originally Posted by cficare68

Ive been searching for the better part of a week now and can not get a direct answer to this question. Long story I lost 1st gear in my transmission on my 2011 135i. The car will go into gear and start to move forward but will throw it out of gear. 2nd threw 6th and reverse works great. Which leads me to believe ive damaged a bearing internally or chipped a tooth off of first.

My first option was to have it rebuilt but upon researching it appears that bmw has decided to be greedy and not sale the internals to these trans. Which has left me with two options. Option A. A used trans which will run me 2000 to 2900 dollars. Or option B a new trans from BMW for around 3600.

So im now left wondering if i were to get a n54 trans (which is more than half the price of a n55 trans with more availability) would it work. From what i have read the belt housing should bolt up with out an issue cause on the 4 cylinder and 6 cylinder motors bmw has been using the same bellhousing since the 70s. Also with the 1m using a n54 motor and a n55 trans i would assume the input shafts would be the correct spline count as well.

Does anyone know if in fact if it would be a direct fit? Cause i can seem to find a direct answer. Just bits and pieces that there is a possibilty of it working.

Thanks in advance.

I know it's a bit late of a reply here but I just saw this, if you haven't already fixed the car maybe this could be of some help.

The main difference between the two transmissions is the input shaft inside the trans. On the N55, the transmission has a male shaft while the flywheel has a female pilot bearing. On the N54 transmission, the flywheel has the male shaft, and the transmission holds the female pilot bearing. So theoretically, you would be able to run the N54 transmission, but you would need to find a 6-bolt N54 flywheel with the male shaft (and a couple other small parts for the shifter.) That's why I'm in search of one right now, I'm trying to swap my N55 auto trans. to a manual and I bought a 2009 N54 manual trans. to do it with.

[cficare68]

Originally Posted by rich_mane

I know it's a bit late of a reply here but I just saw this, if you haven't already fixed the car maybe this could be of some help.

The main difference between the two transmissions is the input shaft inside the trans. On the N55, the transmission has a male shaft while the flywheel has a female pilot bearing. On the N54 transmission, the flywheel has the male shaft, and the transmission holds the female pilot bearing. So theoretically, you would be able to run the N54 transmission, but you would need to find a 6-bolt N54 flywheel with the male shaft (and a couple other small parts for the shifter.) That's why I'm in search of one right now, I'm trying to swap my N55 auto trans. to a manual and I bought a 2009 N54 manual trans. to do it with.

Just saw this thank you. Still haven't fixed the trans yet. (just been dealing with not having a first gear) But I will also be picking up an 09 trans in the next couple of weeks. Did you ever complete the swap?

[bbnks2]

Originally Posted by cficare68

Just saw this thank you. Still haven't fixed the trans yet. (just been dealing with not having a first gear) But I will also be picking up an 09 trans in the next couple of weeks. Did you ever complete the swap?

Pilot bearing is easily pressed put of the n55 flywheel no issue there at all... the issue is the driveshaft is a different length. I've also read the shifter doesnt sit at the same position anymore but not sure on how true that is... the shifters are interchangeable between n54 and n55. My guess is that the selector rod is different on some cars like xi and it's not actually the shifter that's the issue.

[Troy T8]

Did you make any progress on this? I am running into the same situation. And would like to do n54 trans if possible

[rich_mane]

Originally Posted by bbnks2

Pilot bearing is easily pressed put of the n55 flywheel no issue there at all... the issue is the driveshaft is a different length. I've also read the shifter doesnt sit at the same position anymore but not sure on how true that is... the shifters are interchangeable between n54 and n55. My guess is that the selector rod is different on some cars like xi and it's not actually the shifter that's the issue.

The flywheel bit is true for sure, when I was doing my swap I only had an AT flywheel anyway so I just went for the one that matched the tranny I was buying at the time. OP could just reuse his and press the center out. I don't know for sure about the driveshaft in this situation though. I ended up just reusing my AT driveshaft and pulling it apart to get the length I needed. Still uses the entirety of the splines so no worries and no problems for me yet. Shifter fits perfectly in my car, I had to use an N54 shift bracket and i'm pretty sure an N54 selector rod as well.

Originally Posted by cficare68

Just saw this thank you. Still haven't fixed the trans yet. (just been dealing with not having a first gear) But I will also be picking up an 09 trans in the next couple of weeks. Did you ever complete the swap?

Originally Posted by Troy T8

Did you make any progress on this? I am running into the same situation. And would like to do n54 trans if possible

Yes I completed the swap just over a year ago and it's been running great ever since. Haven't had any problems with it.

[cficare68]

Originally Posted by bbnks2

Pilot bearing is easily pressed put of the n55 flywheel no issue there at all... the issue is the driveshaft is a different length. I've also read the shifter doesnt sit at the same position anymore but not sure on how true that is... the shifters are interchangeable between n54 and n55. My guess is that the selector rod is different on some cars like xi and it's not actually the shifter that's the issue.

According to ECS tuning the manual transmission driveshafts are the same part number. However if they are wrong and you are right amd they are wrong I can get the driveshaft out of the 09 135i im getting the trans out of. Since he is swapping the car to a LQ9 w/ a 4l60 trans.

[cficare68]

Originally Posted by Troy T8

Did you make any progress on this? I am running into the same situation. And would like to do n54 trans if possible

Yes i picked up the transmission today from my friend. The trans came with the shifter arm assembly as well and just ordered the flywheel about an hour ago. So im playing the waiting game now. Looking online for the n55 trans the cheapest i could find the transmission for was $2,000 with 120,000 miles on it. Thus far into this swap i a $800 bucks and all that i have left is the trans fluid.

[bbnks2]

Originally Posted by cficare68

According to ECS tuning the manual transmission driveshafts are the same part number. However if they are wrong and you are right amd they are wrong I can get the driveshaft out of the 09 135i im getting the trans out of. Since he is swapping the car to a LQ9 w/ a 4l60 trans.

N55 (GS6-45bz)
Manual drive shaft transmission L=1385MM 1 26107614420
Driveshaft, dual-clutch transmission L=1353MM 1 26107614424

N54 (GS6-53bz)
Manual drive shaft transmission L=1371MM 1 26107567933
Drive shaft automatic transmission L=1373MM 1 26107574680

Who lists them as being the same? There might be enough slack in the yoke to pull the N55 driveshaft the extra 14mm but you would have to figure that out yourself.

[cficare68]

Originally Posted by bbnks2

N55 (GS6-45bz)
Manual drive shaft transmission L=1385MM 1 26107614420
Driveshaft, dual-clutch transmission L=1353MM 1 26107614424

N54 (GS6-53bz)
Manual drive shaft transmission L=1371MM 1 26107567933
Drive shaft automatic transmission L=1373MM 1 26107574680

Who lists them as being the same? There might be enough slack in the yoke to pull the N55 driveshaft the extra 14mm but you would have to figure that out yourself.

Stated in the post where i found my info from. Also previous too already was if need be i have a driveshaft from the same car i got the transmission from. Regardless this is not an issue at this point. But for the sake of finding out what is necessary i will try the stock n55 drive shaft first and swap to the n54 one if necessary.

[cficare68]

Still working on this swap. Just been dealing with no first gear driving around on the stock trans. Haven't gotten a chance to go grab the n54 driveshaft yet but I think i might just try the swap with the n55 driveshaft. If the N55 driveshaft is 14mm longer than the N54 i don't see there being an issue with it.

[Hannibal4444]

Were you able to reuse your original driveshaft? I'm thinking about replacing my GS6-45bz with a GS6-53bz. My driveshaft comes out to being 15mm longer. So a similar difference in your situation.

[ShocknAwe]

Be better off trying to retrofit the zf8. Can't remember the designation of the unit that has been swapped in by others.

[13A1AH]

I just want to clear up some stuff on the 45bz to 53bz trans swap I’ve seen after I’ve just done it to my 135i, I’ve seen a lot about how you can just press the input shaft from the n54 into the n55 flywheel, you can’t the shape of the rest for the flange on the backside of the input shaft doesn’t work correctly and the holes are different sizes. Also want to say that you can run the slave cylinder, and driveshaft from the n55 car. One more thing is that you do have to extend a little reverse wiring harness super easy just 2 wires. Hope I can clear some stuff up for some people save them a headache.
Also horsepower freaks and garageholics have good removal and install videos
If your having a hard time finding a 6 bolt n54 clutch look at X clutch kits, there’s also a spec single mass steel flywheel that I bought you will have some gear chatter if you run oem clutch like I did not too bad though.

[Keviendo]

How did it go with swapping the N54 MT while keeping the N55 MT driveshaft?

[moose09876]

Originally Posted by Keviendo

How did it go with swapping the N54 MT while keeping the N55 MT driveshaft?

Well.... I forgot the auto driveshaft at my house when I went to a friend's with a lift to swap, so I used the manual shaft. It's definitely tight, but doable. I put the guibo side in first, then the differential side, it was definitely a squeeze. Loosely attached the carrier bearing, tightened both ends, then snugged down the carrier bearing where it wanted to rest which was a little different than factory. Getting it in place is the hard part, once it is in it will relax and go into place. I have ~25 mi on it so far with no issues that I can tell.

[Keviendo]

Originally Posted by moose09876

Well.... I forgot the auto driveshaft at my house when I went to a friend's with a lift to swap, so I used the manual shaft. It's definitely tight, but doable. I put the guibo side in first, then the differential side, it was definitely a squeeze. Loosely attached the carrier bearing, tightened both ends, then snugged down the carrier bearing where it wanted to rest which was a little different than factory. Getting it in place is the hard part, once it is it will relax and go into place. I have ~25 mi on it so far with no issues that I can tell.

Nice! I’m glad that you managed to squeeze it in.