E46 M3 M-Diff vs E86 Z4M M-Diff ... differences?

[maupineda]

Originally Posted by Vanne

So they are different.. even to open. The E46 m3 is a breeze compared to the z4m diff.. nearly impossible to open.. have to drill out the locking ball bearing and then get a 4 meter extension bar on a specially made mount in a press.. let's just call that bloody hard...

Anyways, decided after opening the diff to just buy a proper LSD.

Hi, any pictures you could share, I am planning to rebuild mine with new clutch packs and a 4.1 gear set

[Vanne]

How are you going to open it?

I might shoot some pics when I get down the shop next time when my diff arrives

[F360C]

Originally Posted by Vanne

How are you going to open it?

I might shoot some pics when I get down the shop next time when my diff arrives

What LSD did you end up going with? I was going to buy replacement clutches from RacingDiff for the stock LSD but they advised it would be almost impossible to get open.

I am looking at their 4 clutch set up paired with a 3.91 or 4.10. Originally i was all 4.10 but i am wondering now if it might be too short on some occasions.

[maupineda]

Originally Posted by Vanne

How are you going to open it?

I might shoot some pics when I get down the shop next time when my diff arrives

If I have gotten it right, you need to split it just like the E46M3...

remove the ring bolts
press or tap out the ring out
remove the small screws on the backside of the ring seat
split the upper part open

^^ Watch from 3:52 through 5:30

I know is a different carrier, hence why I ask if the bolts' array is different

if you could point how different the process would be, it will help greatly.

[GuidoK]

Interesting video.
But who noticed 2 important steps that he forgot? (or at least: didn't film )

[maupineda]

I have reached out to them and got a very detailed answer, so yes, the diff is different and to open you need a special tool (can be made up) and drill a steel pin/ball out that secures the cap, then unscrew the whole cap.

The Z4M uses the V2 of this design, as well as some late production M3s, and so is shared with the E92 and E60, and it has an additional set of clutches, so I think V2 can handle more torque as it was used on the V10 engine.

To the above point, backlash and mesh can be skipped if no change to the gearset. they said 100% of the time they checked it both come back on point. if you change the gearset, shimming the carrier is all that is needed. they really seem to know these diffs inside out, something I did not get with the US suppliers. I mean, changing bearings and crush sleeve is nothing special other than the intese labour and specialty tools required for it.

[GuidoK]

Originally Posted by maupineda

To the above point, backlash and mesh can be skipped if no change to the gearset. they said 100% of the time they checked it both come back on point. if you change the gearset, shimming the carrier is all that is needed. they really seem to know these diffs inside out, something I did not get with the US suppliers. I mean, changing bearings and crush sleeve is nothing special other than the intese labour and specialty tools required for it.

I would never skip on backlash (that was one of my points).
Especially as it's a measurement that takes maybe 30 sec to do.
They change bearings. So measuring backlash is the fastest and simpelest of measurements to immediately see if something's wrong. For example the bearings could be slightly out of spec or not seated properly. That is why you do that.
So to me this is cutting corners. It has nothing to do with knowing diff's inside out. A diff is quite a simple machine. They don't follow workshop manual procedure if they don't measure the backlash. And I don't mean jsut BMW's workshop manual procedure, but virtually all manufacturers workshop manual procedures.
Skipping on blueing the gears if the gearset isn't changed I can imagine. That is also a lot of work. But backlash? nah.

The second thing is that they don't secure the central nut securing plate on the input axis.

[Vanne]

Got my diff back, well the outer case is the only thing that's still original from the upgrade. I ended up buying a custom race diff from them in Cerbia, and got it installed by Gear Masters here in DXB (.) anyways, pumking came in a nice box and included new output shafts.

Took a week or so before it was all back together plumbed in with a temp sender. The preload is tight, but will loosen up a bit I'd say, and the backlash is 0.08. which to me is a lot, however when I checked with the supplier, said it's nicely in spec.

Looking forwards to running this in a bit..

https://www.racingdiffs.com/collecti...33671153090695

And specified for circuit racing..
1.5 way (30°/60° ramp angle) Maximal number of active clutches.





backlash set.


Temp sensor plumbed into the case.

Running in will be very easy hardly no load 20 minutes, then cool down 30 mins, another 20 mins at low load, then another 30 mins cooling and then 30 minutes at medium stick. Then 30 mins cool, and then 20 mins at full stick, then swap oil and done.

[F360C]

Originally Posted by maupineda

I have reached out to them and got a very detailed answer, so yes, the diff is different and to open you need a special tool (can be made up) and drill a steel pin/ball out that secures the cap, then unscrew the whole cap.

The Z4M uses the V2 of this design, as well as some late production M3s, and so is shared with the E92 and E60, and it has an additional set of clutches, so I think V2 can handle more torque as it was used on the V10 engine.

To the above point, backlash and mesh can be skipped if no change to the gearset. they said 100% of the time they checked it both come back on point. if you change the gearset, shimming the carrier is all that is needed. they really seem to know these diffs inside out, something I did not get with the US suppliers. I mean, changing bearings and crush sleeve is nothing special other than the intese labour and specialty tools required for it.

Bringing this old thread back but has anyone rebuild the GKN2 LSD in our cars and can share the process for getting the LSD itself open?

maupineda You don't happen to still have their detailed response you could forward me?

So close to pulling the trigger on the RacingDiff clutch pack but want to know what I am in for in terms of install.

[Vanne]

Opening ours up is pretty much impossible unless you make the "key" that fits in these 6 slots around the inside of the perimeter.

And if you look closely you'll note where you can see that the locking ball bearing has been drilled out.



Absolutely nothing like the m3 diff.. whitch has like 6 bolts, undo and take apart, easy peasy..

Lol yeah that video shows the m3 casing, completely different to ours. If I drop back into the shop, I'll take a picture of the "key" since I payed for him to make it. Lol. Or you could contact Sava in Dubai and ask him. Nice bloke, smokes a lot..

We cracked open the case with the "key" with a 4 meter extension bar and 4 big guys on it... It's not an easy job, that's for sure.

You'll need to order the specific z4m clutch pack kit, as after we opened mine up we discovered that the E46 has 2 clutches less than the z4m, which is why Racingdiffs.com now offer a specific pack for the z4m.

Hope that helps , explains a bit..

Oh and after cracking the diff, I decided to just put in a proper race diff from them. Lifetime Warrenty.. gotta love that.. 30/60 ramps. Got it at a pretty darn good price, seeing as we were sharing info with Racingdiffs.com


(GearMasters Dubai, UAE)

[F360C]

Originally Posted by Vanne

Opening ours up is pretty much impossible unless you make the "key" that fits in these 6 slots around the inside of the perimeter.

And if you look closely you'll note where you can see that the locking ball bearing has been drilled out.

Attachment 2585344

Absolutely nothing like the m3 diff.. whitch has like 6 bolts, undo and take apart, easy peasy..

Lol yeah that video shows the m3 casing, completely different to ours. If I drop back into the shop, I'll take a picture of the "key" since I payed for him to make it. Lol. Or you could contact Sava in Dubai and ask him. Nice bloke, smokes a lot..

We cracked open the case with the "key" with a 4 meter extension bar and 4 big guys on it... It's not an easy job, that's for sure.

You'll need to order the specific z4m clutch pack kit, as after we opened mine up we discovered that the E46 has 2 clutches less than the z4m, which is why Racingdiffs.com now offer a specific pack for the z4m.

Hope that helps , explains a bit..

Oh and after cracking the diff, I decided to just put in a proper race diff from them. Lifetime Warrenty.. gotta love that.. 30/60 ramps. Got it at a pretty darn good price, seeing as we were sharing info with Racingdiffs.com

This is great info Vanne!

I would love a pic of the key.... I have found a couple tools online that I think might work. Any chance you could measure the tool for me when you see it?

I am wondering if this would work?

http://www.langtools.com/sku-2770-6-...1-ton-dana-44/

[maupineda]

Originally Posted by F360C

Bringing this old thread back but has anyone rebuild the GKN2 LSD in our cars and can share the process for getting the LSD itself open?

maupineda You don't happen to still have their detailed response you could forward me?

So close to pulling the trigger on the RacingDiff clutch pack but want to know what I am in for in terms of install.

I can, forward me your email address and I will send what racediffs responded to me.

But is not much more detailed than Vane’s

[F360C]

Originally Posted by maupineda

I can, forward me your email address and I will send what racediffs responded to me.

But is not much more detailed than Vane’s

Thanks for the email! I wish they had more detailed instructions. I am tempted to try it.

Wonder if the would work as the key to open it?

[maupineda]

Originally Posted by F360C

Thanks for the email! I wish they had more detailed instructions. I am tempted to try it.

Wonder if the would work as the key to open it?

I may do it if I am able to source a 4.1 gearset. I saw the tools, but I do not know the diameter. if we get the dimensions of the tool and ask racingdiffs, the ones for the diff and the spacing of the tabs, we would know for sure.

[Vanne]

Open only if your interested in swapping the clutches for a new set. I had 200k kilometers on mine, the clutches were in semi ok nick. I think the hydro-swash plate (i look at this thing and it reminds me of a helicopter swash plate)- does a good job. So the only real reason to open it is to replace the stock clutches.. you cant add extra ones as then you cant close it up anymore. When I found out I wasn't able to add more clutches, that's when I went down the race diff route.

So your either going to end up with a stock/re-furbed Mdiff , or at that stage your going to drop in a diff from one of the many other manufacturers..

ill show you my plates that came out.

[F360C]

Originally Posted by maupineda

I may do it if I am able to source a 4.1 gearset. I saw the tools, but I do not know the diameter. if we get the dimensions of the tool and ask racingdiffs, the ones for the diff and the spacing of the tabs, we would know for sure.

Picked up the oem Motorsport 4.10!

Motorsport 4.10 by Adam McGregor, on Flickr

Originally Posted by Vanne

Open only if your interested in swapping the clutches for a new set. I had 200k kilometers on mine, the clutches were in semi ok nick. I think the hydro-swash plate (i look at this thing and it reminds me of a helicopter swash plate)- does a good job. So the only real reason to open it is to replace the stock clutches.. you cant add extra ones as then you cant close it up anymore. When I found out I wasn't able to add more clutches, that's when I went down the race diff route.

So your either going to end up with a stock/re-furbed Mdiff , or at that stage your going to drop in a diff from one of the many other manufacturers..

ill show you my plates that came out.

Thanks for the pics Vanne!

This is basically what I want to do... just refresh the stock LSD. I would love a drexler or RacingDiff uograded LSD but I have already spent too much on the car this year. If i can get the LSD open I can can refresh it with slightly better clutches for $600 vs $3K for an upgraded LSD.

Any chance that shop wants to sell the tool to open the diff or make another?

[maupineda]

I have my 4.1 gear-set coming also. I have decided against refreshing the clutches as my car has only 78k km, and have no indication of any wear issue, so I will only replace the bearings and cross the rebuild bridge when I really have to.

Were did you get yours? I had to pay a big penny for mine 😳

[maupineda]

I got my 4.1 OE Motorsport gear set

It will definitely take some time before I am able to install it, but maybe mid this summer.

[F360C]

Originally Posted by maupineda

I have my 4.1 gear-set coming also. I have decided against refreshing the clutches as my car has only 78k km, and have no indication of any wear issue, so I will only replace the bearings and cross the rebuild bridge when I really have to.

Were did you get yours? I had to pay a big penny for mine 😳

I got mine through an employee order.

I am not in a huge rush to install either... I am planning mid summer like you. My only question now is what bearings to go with. The E46 M3 LSD uses the roller bearings for the pinon but the GKN2 in our diffs uses ball bearings . Slightly different design and I dont know if it would really make a difference if I used the old bearing design vs the new one.

The only thing is the E46 M3 style bearings are easily available from diffsonline where as the newer style ones are much harder to find. Racing diff sells them but you need to buy all the bearings for the diff in a kit instead of just the 2 for the pinon.

[maupineda]

Originally Posted by F360C

I got mine through an employee order.

I am not in a huge rush to install either... I am planning mid summer like you. My only question now is what bearings to go with. The E46 M3 LSD uses the roller bearings for the pinon but the GKN2 in our diffs uses ball bearings . Slightly different design and I dont know if it would really make a difference if I used the old bearing design vs the new one.

The only thing is the E46 M3 style bearings are easily available from diffsonline where as the newer style ones are much harder to find. Racing diff sells them but you need to buy all the bearings for the diff in a kit instead of just the 2 for the pinon.

I am using racing diffs, the kit is really affordable, even if I don't use the output shaft bearings is still not too expensive. I think diffsonline do have a kit for the Z4M, but is almost twice as expensive as the racingdiffs one and it also comes with the output flange bearings.

My plan is to get a new bearing on the pinion only, my car is 78k kms so I am not changing output flange ones at this point. I will also buy the shim kit from racing diffs in case I need to adjust the meshing, but I have been told that is very possible the 4.1 gears goes fine, being an OE item ensures tolerances are all within the same range, thus making fitting issues less probable.

[Vanne]

Ill ask next time i am down that way, probably after eid id imagine. def need the shim kit..

[flory]

Hi there, have you guys ended up using the RacingDiffs set to refurbish your diffs and have you been happy with it?