Is a new gearbox a solution for the "well known" problem???

[Franzino]

Unfortunately my gearbox has the same issues as a lot of other Z4M owners . I’m not asking if this problem is normal, because there are threads everywhere about this on forums. But I have a question were I did not find the answer for.

Problem
Shifting from first to second is not going so smoothly as in the other higher gears (there is a big difference). It's really jerky going from first to second gear. But it does not make a grinding noise on my car, like other Z4M owners report. I have to be aware when shifting from first to second and downshifting from third till second. I feel that there are a couple of big resistance points that you have to go through when shifting to second gear. It's pretty hard to constantly be aware of it. It is seriously the only flaw I think my car has, but I still love the Z4M. I'm going to be doing the CDV delete soon, which I hear helps the problem a bit…but it’s not a cure for the problem.

Question
My Z4M has 40.000KM (25.000 miles), is still under warranty and my BMW dealer is a personal friend of me. I have told them the problem with the car and their head technician drove my car. He could feel the stiff first till second gearshift and he said it was normal for the Z4M. The only thing they could do at the time was changing the oil of my gearbox (it’s a small improvement). You can not order any spare parts of the Z4M ZF gearbox! When driving an E46 M3 I never had this issue with the manual gearbox, that’s because they don’t share the same gearbox. The gearbox in the e46 M3 is from Getrag and the one in the Z4M is from ZF. The M3's original six-speed doesn't fit the Z4's chassis.

Solution?
If I really want, there is a small chance they will replace the gearbox with a new one (under warranty). My Z4M is from building year 2006, but will a newer gearbox be the solution for the problem? Did the Z4M’s that were produced in 2007 and 2008 have the same gearbox problems? Is there a building year when the gearbox problem did not occur? The reason I ask… If I decide I want a new gearbox then I certainly don’t want the problem to get worse. Maybe a new gearbox will even be worse and is going to grind as a lot of other Z4M owners report. I would be nice to see the problem disappear, but it will be a nightmare if the problem got worse…

What do you guys think?

I have found this on Wikipedia:

"It is widely reported on owner forums that the 6-speed gearbox in the 2006 & 2007 M roadsters and coupes is prone to grinding when shifting from 1st to 2nd gear at high rpm. According to reports, there has been mixed response by BMW dealerships to this issue, some owners claiming to have received entirely-new gearboxes and others claiming their dealer calls the grinding "normal"."

By the way: The Z4M is a great car, but the build quality is not BMW's best effort. It's a shame that the Z4M gearbox has this problem and there was not a solution from BMW (as BMW did with a solution for the e46 M3 engine problem).

 

[Wondermike]

TBH I think they're all the same. Don't think a new gearbox will be any better.

Just take it easy until you're in 2nd gear, then you can nail it 8)

 

[mmm-five]

Not had any problem with grinding at all with mine, and a lot of sports cars have stiff/notchy gearboxes - I know the e34 M5 Getrag 420 box was notchy between 1st and 2nd unless you were committed.

 

[peddy]

I reckon the CDV delete should sort this out.

 

[dgm]

I don't think removing or adapting the CDV will make any difference at all to the characteristics described by the OP which are, as far as I'm concerned, totally normal for the vehicle.

I think you're stressing over nothing, the gearbox in the Z4M behaves in the manner described and the E46 M3 was exactly the same. As for grinding, I've never experienced that or heard it to be a particularly prominent problem on these cars. When your gearbox develops a genuine problem you'll know about it straight away, at least I did with mine when the input shaft became loose and sounded like a bag of spanners at low speed and as if the car was being hit from below with a sledghammer when changing at high speed.

My gearbox was changed due to this at 26,000 miles and the new box was behaved no differently to the original one prior to the above issue. I wouldn't give Wikipedia much weight in relation to this personally.

 

[daz05]

I had some complaints about my 1st to 2nd change when I first got mine. No grinding but it wasn't quite right sometimes. I reported it to the dealer and my clutch was changed under warranty. Since then I have had no more problems.

 

[Beedub]

i have no grining issue at all, and i dont struggle at all with shifting from 1-2 or any gear at all, i always read these issues and think im not suffering from this problem ........

try some fresh fluid maybe?

 

[api330]

I tried 3 cars when i brought mine and they where all the same,(not grinding just needed a firm hand) as i said in my post removing the valve made a big differance, If you look at valve when you remove it and have a look the hole for the fluid to pass though is tiny so it must cause slave cylinder to move a lot slower then it would with no restriction in the fluids path, It made mine loads better, If you try selecting gears with car switched of you can here and feel the macanical effort needed to select gears its a solidly built gearbox for sure, One last point i pull away in second gear (unless i am after a mega quick getaway and even then theres a lot of people who say you get a quicker 0 to 60 with second gear start) first gear is so short that second gear start is so easy, You soon get used to box, but making it a bit nicer is a good thing,

 

[playalistic]

Just a notchy box as others have said. It is a sports car after all

 

[Franzino]

Thanks for the input,

I hear some people say; “this is how the gearbox of a sport car feels”… It's partly true, but I can’t agree with the whole statement. I have driven Audi RS4, e39 M5, e46 M3, Lotus Elise, Lamborghini Gallardo, Porsche Carrera, Cayman S, Boxter S, S2000. Indeed those gearboxes are stiffer then driving a 1.9TDI and that’s totally normal when you have a high power sporty engine. But, none of the second gears of those cars felt as stiff as the second gear of the Z4M. In my opinion there is also no comparison in feel between the gearbox of the e46 M3 and the Z4M. They feel different…! The gearbox of the e46 M3 is also stiff, but there is no less accurate second gear issue. By the way; this is based only on personal experience.

The Z4M gearshift between first and second is not only notchy and stiffer, but it also a lot less accurate then in the other higher gears. Every other gear also feels stiff and hard to maneuver, but those gears feel accurate and it’s a joy to move the stick. The problem is only second gear! For the record; yes the gearbox fluids are already changed in my car… So the only things I can do; are replacing the entire gearbox or removing the CDV.

I was just asking myself the question; If I have the opportunity to change the gearbox under warranty should I do it or not… :|

 

[Franzino]

I tried 3 cars when i brought mine and they where all the same,(not grinding just needed a firm hand)

Were those gearboxes stiff in every gear or only in second gear? Did it feel different when shifting to second gear in comparison with the other gears?

 

[dgm]

I can't see why changing the CDV would effect the notchiness/stiffness of the gearbox, it only slightly delays the clutch engaging. My experience is that it has no effect on the operation of the gearbox.

 

[ga41]

Franzino, you could try stiffer transmission mounts for a while and see if that improves it for you.

 

[Z4coupebeaver]

There are a number of factors which contribute to the "issues" associated with the Z4 box.

The CDV makes the change feel strange. I can see no benefit in keeping it.

The clutch plate is a hard wearing high performance unit. This makes the clutch almost switch like and takes skill to learn.

The gearbox oil is a high viscosity fluid and improvements have been reported by chaging to a lower viscosity oil. This will invalidate your warranty but I have never herd of a failure as a result of doing this.

The box is designed with a lot of endfloat on the countershaft. This results in input shaft chatter and a less precise change as well as more strain on the synchro. This is the biggest contributor to the issues associated with this box. It's not a fault but a feature.

I always dip the clutch on switching off as I hate the sound of the internals clattering on my box.

Replacing transmission mounts has been suggested. I've not tried this but that sounds like a worthwhile mod to take up some of the transmission slack

Is it worth changing the gearbox? I'd say no.

The comments about this being a "sports car" is used to justify a number of sins.

 

[api330]

I think saying its a performance car so there for gearbox is stiff is completly incorrect (you could have got away with that statement 15 yrs ago but not with modern cars) i have owned many powerfull cars over my long driving history (i am slighty old) and the Z4m has had the most positive box i have used, if your driving the car hard its feels great very mechanical, its when your driving around town you pick up on it, I have seen verious rd tests of car when they where new on youtube and nearly all tests talk of positive action needed when using gears, As to cars i tried all 1st to 2nd where the harder to get but other gears can be difficult as well, My own car seems better when cold which is strange as most cars boxes get better as they warm up,(many other people have said same thing on verious sites) I may well change my gearbox oil to a different spec when i have done some more research, I also think removing valve helps because making a nice gear change needs clutch fully disengauged and if valve slows down what your left foots doing then you could be trying to select your next gear before your clutch is fully disengauged, My car is is fine as it is and i love it, but these mods imo need to be done to improve car, sorry to have gone on so much,

 

[playalistic]

OK so I'll rephrase. If you don't like it, chop it in for something with a slush box. No point arguing over semantics is there.

 

[api330]

OK so I'll rephrase. If you don't like it, chop it in for something with a slush box. No point arguing over semantics is there.

No arguments from me as i say i love mine..., I had a slk amg 55 which was a great car but the auto box in that did my head in, it was great round town but once on the open road or track and driving hard it was rubbish, You pays your money and takes your choice,

 

[Franzino]

The CDV makes the change feel strange. I can see no benefit in keeping it.

I have bought a replacement CDV from Zeckhausen. So that I can have this changed on my car and keep the original look. I can feel the CDV on my Z4M, but the CDV feeling is worse on my e46. You can feel a real delay on this car.

The clutch plate is a hard wearing high performance unit. This makes the clutch almost switch like and takes skill to learn.

Never had any problems with the clutch. It's a little stiffer on the Z4M, but that's normal considering the power. It always felt normal.

The gearbox oil is a high viscosity fluid and improvements have been reported by chaging to a lower viscosity oil. This will invalidate your warranty but I have never herd of a failure as a result of doing this.

This is something I'm not going to do... On this one, I thrust BMW to say what oil to use.

The box is designed with a lot of endfloat on the countershaft. This results in input shaft chatter and a less precise change as well as more strain on the synchro. This is the biggest contributor to the issues associated with this box. It's not a fault but a feature.

Good to know

I always dip the clutch on switching off as I hate the sound of the internals clattering on my box.

I always switch off the car with the clutch pushed in. No problems with the sound.

Is it worth changing the gearbox? I'd say no.

If it's under warranty..Why not....? You think a never Z4M gearbox would be the same or even worse?

 

[Franzino]

OK so I'll rephrase. If you don't like it, chop it in for something with a slush box. No point arguing over semantics is there.

It's not that I don't like it... The stiff and less accurate first to second gearshift is the only thing were the Z4M loses some points for me. The rest of the car is great! I love the Z4M and it feels special. For this money there is no other car that would suit me better as a second sun and fun car... 8)

 

[Z4coupebeaver]

Is it worth changing the gearbox? I'd say no.

If it's under warranty..Why not....? You think a never Z4M gearbox would be the same or even worse?

After buying my Z4M, I got concerned over the issues we are discussing here. Thanks to many good people in the Z4 forum, I have now experienced 7-8 gearboxes in their cars and found all of them to be pretty much the same.

I wouldn't have the gearbox replaced as it will mean time without the car and opportunity for something not to be put back correctly. I feel the less time a BMW "technician" is working on my car, the less chance that something gets damaged or made worse. I'm a great believer in - if it aint broke don't fix it.

I feel it is very unlikely that the gearbox will be worse and the placebo effect of a new box may make you feel it is improved but the technical issues I've mentioned will be present in all Z4M gearboxes.

I can appreciate your feelings over the use of gearbox oil and I only mention it as this has been a remedy for many other cars that have suffered similar issues.

One very important point on these cars is that the gearbox oil must be changed regularly as the excess end float/chatter will result in more debris contaminating the oil.