GS6-53DZ swap to GS6-45BZ?

[bscsystem]

The 45BZ come with all N55 cars so far I know, mine came from a F20/F22.
The 53BZ can not improved, there are no parts or spare parts on the marked. The 45BZ can hold enough power/torque, it is also an S55 engines with another bell housing. And there are synchron rings as spare parts on the market if there are worn.

Hey,

I'm driving E92 335i N55 and my gearbox is GS6-45BZ - THD4. Unfortunately my first gear pop off every time and there is no gearboxes listed for sale.
So I need to swap my gearbox with Diesel version. What do you think guys, should I take the different gear ratio into account? Is this a big problem?

I won't find any parts for sale tho

 

[Chrysheight]

The 45BZ come with all N55 cars so far I know, mine came from a F20/F22.
The 53BZ can not improved, there are no parts or spare parts on the marked. The 45BZ can hold enough power/torque, it is also an S55 engines with another bell housing. And there are synchron rings as spare parts on the market if there are worn.

Where can one find synchro rings for the 45bz transmission? I just purchased a used 53bz transmission to replace my 45bz, but if replacing the rings is an option, I'd probably like to stick with the 45bz transmission

 

[bscsystem]

well, guys, I bought a new 45BZ transmission and looking to sell the old one.

 

[9krpmrx8]

Anyone know the difference between a GS6X45DZ and GS6X45BZ? I have read conflicting info as to whether the DZ is for diesel cars or not.

 

[vachfolle]

I confirm that DZ is for diesel engine : gear set > B = Petrol/gasoline gear ratio. D = Diesel gear ratio.

 

[Mike111]

I have the 53bz hgy I am trying to put it in a pl33 lci 335ix 09 prod 02/09 ^ ... so far the fly wheel changed to 6 bolt from 8 on that year but I also noticed that the real oem site says dz for diesel? Idk if this will work but I know the n55 trans will not bolt on to an N54 it needs a bell housing plate and also new msd81 not used and a standalone htc unit to control it. So rather put down on a new m series with the cost of that project so I am trying this manual swap , now this trans I bought is from the exact year and it came off of a 335xi pre lci 53bz not dz? I figure this will work concidering it worked on the downer car but I am not so sure as I didn’t pull the part off the car so looking into this noticing the different part number trying to figure if I was givin the right parts. Do you know if this will work or have I been driving a diesel car this whole time? Or is it the automatics 335xi coming in diesel because manual trans say dz and that’s what The site says is compatible which the one I want to swap to the 53bz but don’t know if it will work??

 

[Mike111]

I confirm that DZ is for diesel engine : gear set > B = Petrol/gasoline gear ratio. D = Diesel gear ratio.

So than all the lci manual trans are coming with diesel gear ratio? Because real oem bmw site says dz? what is the difference just the type of car it got put in just to know what it was original stall in ? It does say i need to look into repair manual and show parts I have to replace which are seals and bolts.fly wheel also changes to 6 bolt pattern. Maybe that is the conversion it need to be put from dz to bz if you buy it new unlike the one I bought considering it states bz for gas I should be all set just have to change the fly wheel

 

[Jw219]

Hi! I appreciate nobody has been here for a little while. I'm currently doing an e36 n55 swap and have a gs645bz box going in. The flywheel is obviously not an issue as its an n55 but my transmission crossmember and shifter rod are for an n54 swap so a 53bz. I see people on here talking of shifyer differences but I can't decifer exactly what the difference is between the 45bz and 53bz shifter and whether this would cause an issue. People seem to have done the swap from 45 to 53 and vice versa so I assumed they were the same bar the flywheel?! Theres a guy on this forum that said when he went from 53 to 45 he changed shifter parts? Any help would be appreciated.
Thanks

 

[doublespaces]

Maybe @AzNdevil has some insight on the differences here.

 

[Taymar]

Anyone know for sure if the M2/M3/M4 version of the 45BZ has the same internals, just a different bellhousing?
The price difference between a new n55 45bz and an M4 45bz from BMW is 'only' about $500 bucks.

I've heard you can put an S55 flywheel on an n55 or a 6 bolt n54, and use the M clutch and transmission, but it's nearly impossible to find any info on this or whether the M transmissions are a different length or just a different bellhousing clearance.

 

[CalvinNismo]

I’m not sure about the internals, but the M2/M3/M4 manual is the same length as the M-DCT so they only have to make one prop’ shaft length. (It’s a longer ‘box.)

From what I’ve read the ratios are the same, even though the F8X has a 3.46 rear end.

 

[Taymar]

I’m not sure about the internals, but the M2/M3/M4 manual is the same length as the M-DCT so they only have to make one prop’ shaft length. (It’s a longer ‘box.)

From what I’ve read the ratios are the same, even though the F8X has a 3.46 rear end.

Thank you! I can find info on the DCT setup, but not much on the manual. Any idea if the M4 manual transmission, flywheel, and clutch would work with an n54? (or what issues I may need to overcome).

I was able to find some BMW documentation that did say the M transmissions have some upgrades to handle the extra power; though it was very vague and more of a marketing document than a technical training thing.

 

[CalvinNismo]

Any idea if the M4 manual transmission, flywheel, and clutch would work with an n54? (or what issues I may need to overcome).

Yeah, as long as you have a 6-bolt crank you’ll be fine. N54 and N55 share flywheels across gearboxes (N54 DCT and N55 DCT for example), so the end of the crank is in the same position in relation to the bell housing bolting face. I have a 1M flywheel on my N55.

People use S55 flywheels on N5X DCT’s and the S55 is based on the N55, so I’d be pretty sure the end of the crank position to bell housing bolting face is the same for N54, N55 and S55.

By extending that same logic, the F8X flywheel and twin disc will be fine on an N54 with the F8X gearbox.

I don’t know for sure, but the shift linkage is something that may cause you issues. If I was doing this I’d try the F8X linkage (not sure how similar the chassis mount is to the E-Series cars), or be tempted to try the E9X M3 shift linkage as they came with a twin disc also, so that will be a shorter linkage. Otherwise custom made, or a cut and weld of 2 linkages may be required.

 

[Taymar]

Nice, thank you! Do you think if there is no combo of OE parts that can be combined to put the shifter in the right spot, that I'd be able to get it to work by modifying the linkage and NOT having to cut or reshape the trans tunnel?

Looks like the pre-LCI M2 uses the 'M' transmission, clutch/flywheel all with the n55. LCI then got the s55 and kept most of the same trans parts.

Driveshaft looks like it'll be a tricky one, probably going to need a custom length.

Need to confirm the gear ratios as well on the M trans, looks like they have a slightly shorter rear diff and all that M electronic stuff that I don't want to get into.

If you have a minute, I'd appreciate your option on this one please - If you were in this position - need to buy a new (reman) transmission from BMW, no core to return. I can choose between the original n54 manual trans (GS6-53BZ), the n55 manual trans (GS6-45BZ), or the M2/3/4 manual trans (GS6-45BZ variant).

The cost of the transmissions is pretty high but also similar between the three. I know flywheel/clutch will be more expensive on the M but still doable.

My question is - if you take cost out of the equation, which setup would you go for? I'm targeting around 450-475hp on the n54. Half the people I've talked to are telling me the synchros are very weak, others are telling me they're fine if not abused. I want something that's going to have a good shift feel and last a good amount of time.

 

[CalvinNismo]

I forgot about the OG M2 for some reason, makes sense! If I were you I’d be on eBay for a used gearbox! But that’s not what you asked!

If starting from scratch, I’d go for an E-Series ‘box and I’d go for the N55 GS6-45BZ. It’s 12kg lighter than the GS6-53BZ and could save some fitment headaches in comparison to the F8X GS6-45BZ. If you already have all of the GS6-53BZ bits, shifter, prop’ and the like, I’d probably stick with that and spend the money saved on other nice bits.

I think fitment of the F8X manual in the tunnel will be fine as the DCT fits fine, and I understand them to be similar sizes, but don’t know for sure. You might be able to use an E-Series DCT shaft with the F8X ‘box if you do go for that, length-wise it should be pretty close! I’m sure you could get a shifter to work, but will it be optimal and a good shift?

 

[Taymar]

Thank you! I've actually been scouring ebay since considering the F8X manual from the M cars... such a hard call as I'm looking at about half the price vs. new. The E series boxes are not quite that big a gap.

The downside, all the M3/4 cars I've seen have been in massive wrecks, presumably because the higher value of the M cars takes a lot more body damage to total. Transmission Crossmembers and shifter brackets snapped off due to impact. I'm a bit scared what those kind of shock loads could mean for the internals, since no parts are available.

I think you're right on the money with the DCT shaft, looks like there's one that's just 2mm difference!

I did just grab a used M4 shifter, shift rod and bracket on ebay, thinking it's a relatively inexpensive way to at least measure and compare the shifter setup.

Do you think the GS6-45bz will hold up ok over the long run? I've heard a lot of anecdotal stories about the carbon synchros being fragile and starting to crunch the 1-2 shift after a relatively low mileage. However, I don't know how many of these stories came from the original owners, and whether they were mechanically sympathetic.

Really appreciate the advice; I think I'm leaning towards the e series 45bz. If the F8x shifter linkage measures very similarly to the e series n55 version, I may roll the dice on an M gearbox if one comes along at the right price. I'm kind of curious about it now. Master cylinders are all the same, slave cylinders are the same bore and appear to be the same connector, but different part number. So really it'd just be shifter position and propshaft like you said.

 

[CalvinNismo]

Do you think the GS6-45bz will hold up ok over the long run? I've heard a lot of anecdotal stories about the carbon synchros being fragile and starting to crunch the 1-2 shift after a relatively low mileage. However, I don't know how many of these stories came from the original owners, and whether they were mechanically sympathetic.

I think it’ll be fine! The used market F8X ‘boxes should be in better condition really than N55 variants as they should have been auto-rev-matched most of the time.

Mine has been fine so far, no qualms, but the oil has been changed twice in mine, and I am mechanically sympathetic. It’s a nice shifting gearbox in my opinion.

 

[Taymar]

I think it’ll be fine! The used market F8X ‘boxes should be in better condition really than N55 variants as they should have been auto-rev-matched most of the time.

Mine has been fine so far, no qualms, but the oil has been changed twice in mine, and I am mechanically sympathetic. It’s a nice shifting gearbox in my opinion.

Thank you! That's a great point on the rev matching.

I have obtained a manual shift lever, bracket, and selector rod from an M4 and one from an e series n55 car. The front and rear mounting locations appear nearly identical. The ball joint of the M4 shifter sits about 1.75 inches higher up and about 1" further back. The selector rods are different, n55 is a ^ shape while the M4 is thicker and shaped like an S. The connection point at the front does seem to be in about the same position, though. If clearance isn't an issue I would venture to say the n55 shifter assembly might work with the M4 box.

Flip side, the height increase of the M4 unit might actually be kind of nice, brings the shifter closer to the hand without increasing throw. The fact that it's located further back could need some modification however. I'll try and get some photos and maybe document it in a thread if I wind up going the M4 route.

Thank you again for the help!

 

[sonicnofadz]

Thank you! That's a great point on the rev matching.

I have obtained a manual shift lever, bracket, and selector rod from an M4 and one from an e series n55 car. The front and rear mounting locations appear nearly identical. The ball joint of the M4 shifter sits about 1.75 inches higher up and about 1" further back. The selector rods are different, n55 is a ^ shape while the M4 is thicker and shaped like an S. The connection point at the front does seem to be in about the same position, though. If clearance isn't an issue I would venture to say the n55 shifter assembly might work with the M4 box.

Flip side, the height increase of the M4 unit might actually be kind of nice, brings the shifter closer to the hand without increasing throw. The fact that it's located further back could need some modification however. I'll try and get some photos and maybe document it in a thread if I wind up going the M4 route.

Thank you again for the help!

Taymar, you and I have similar thoughts about using the gs6-45bz transmission from the M2/3/4 on the n54/n55. I have just ordered a low mileage one from ebay that is out of a 2015 f80 M3, for about the same price as a clapped out gs6-53bz. I plan on using this transmission on my 6 bolt n54 (2009 E90 335i) with the factory s55 clutch/flywheel. The gs6-45bz (SHBT variation) out of the M f8X cars is pretty stout, there are guys that have put down north of 700whp without breakage, the internals are apparently not the same as the n55 variant, though the exact differences remains a mystery...For use on n54/e90 I suspect one might need to fabricate or modify the shifter, and maybe also the driveshaft, because this transmission is longer than the variant that comes with the n55 (bell housing is longer). If this works, this might be a good option for n55/n54 guys. I much prefer the shift quality and feel of the gs6-45bz, vs the gs6-53bz, and it is getting harder and harder to find a decent 53bz trans for a good price. Wish ZF offered replacement parts for these things! I have a couple other projects in my shop, so won't be able to commence on this project until Jan or Feb, but I will post back with my findings, and probably also make a youtube video if things work out.

 

[Taymar]

Taymar, you and I have similar thoughts about using the gs6-45bz transmission from the M2/3/4 on the n54/n55. I have just ordered a low mileage one from ebay that is out of a 2015 f80 M3, for about the same price as a clapped out gs6-53bz. I plan on using this transmission on my 6 bolt n54 (2009 E90 335i) with the factory s55 clutch/flywheel. The gs6-45bz (SHBT variation) out of the M f8X cars is pretty stout, there are guys that have put down north of 700whp without breakage, the internals are apparently not the same as the n55 variant, though the exact differences remains a mystery...For use on n54/e90 I suspect one might need to fabricate or modify the shifter, and maybe also the driveshaft, because this transmission is longer than the variant that comes with the n55 (bell housing is longer). If this works, this might be a good option for n55/n54 guys. I much prefer the shift quality and feel of the gs6-45bz, vs the gs6-53bz, and it is getting harder and harder to find a decent 53bz trans for a good price. Wish ZF offered replacement parts for these things! I have a couple other projects in my shop, so won't be able to commence on this project until Jan or Feb, but I will post back with my findings, and probably also make a youtube video if things work out.

Very cool, thank you. I haven't sourced a transmission yet but I have picked up a shift lever and support bracket from both an M car and a non-M. The mounting points look like they're a match; however the casting is different in the center section. The selector rod is also different. I believe the M lever sits higher up. I will try and get a couple of pics and measurements to compare. I think you're right on the driveshaft too. I'm wondering if it's possible to combine the front section from one model and rear section from another to get the correct length.