[dannyle27]

Any 6AT guys having problems with shifting in higher RPM's?

My mods:
Jb4 / BMS e85 PI/TBI BEF
N20 tmap
E51 map 3 adder 75 or map 6 targeting 25
Alpina tcu flash
Rest in signature

So in 3rd, around 4500rpm-5000 rpm, I can hit 25psi but immediately, the rpms shoot up to redline and bounces and it feels like I hit a brick wall until I shift... Kinda like when your charge pipe pops off and you lose all boost.

Not sure if I should be looking into the backend flash demanding too much load or if my transmission is actually slipping. I tried putting the car on the dyno a couple weeks ago at a local event and got 460 whp at 4600 rpm and got kicked into dsc malfunction.

Ugh. Haha

[Cory S]

Peak TQ would probably be around 4500rpm... If the tach shows RPM rise faster than acceleration, while the transmission remains in the same gear, then it is indeed slipping.

Mine hasn't done this yet while accelerating, but it has done this while leaving from the foot brake (brake boosting) at 12-13psi)....

[04gto]

I never experienced any slipping in my trans until I went over about 420 torque at the wheels. My car is 2008 with 79k miles. Car had only 40k when I bought it 2 years ago in excellent condition. After I went FBO (60k miles)and started running e40 etc I got horrible slipping, gear hunting, failed shifts and tranny limp mode. After a few days I could not get on it at all without the gear symbol appearing on the dash. I started doing a bunch of reading. ZF technical manuals, troubleshoting manuals and endless online forum searches.

What I discovered:
1. Online forums can be an amazing source of knowledge. Save you a ton of time. But when it comes to very technical\complicated things like an auto transmission, the info is only good if you know what info to ignore. The only way to know what to ignore is to have an existing knowledge of the subject. 95% of the online "advice" on the subject of our transmissions are completely wrong.
2. The 100k (or whatever) recommended service for our transmissions is BS. If you drive your car hard at all, or drive in a lot of stop and go traffic or live in an extreme climate, it should be changed at about 40 or 50k miles. If you take apart your Mechatronic and rebuild it like I did, you will understand the before and after benefits of this.

I have been working on cars since I was about 17 years old (40 now). I have rebuilt a few engines big (Chevy 454) and small (Honda 125) but I have never touched the internals of an auto tranny before.

I ordered all the parts to rebuild the Mechatronic unit from CTS. Solinoids, Zip kit, sleeve, fluid, pan, filter etc.

The results? Amazing difference! Shifting was super crisp and smooth, no gear hunting, no limp mode.

Slipping? If I drive it agressively in auto (sport or regular) it will still sometimes slip between 4th and 5th. But if I shift it manually there is zero slipping.

Why is it still slipping? Based on all my reading. (Again from technical service manuals or materials written by professional mechanics or the transmission manufacturer). There was some damage already done to the clutches between 4th and 5th gear.

I am certain the tranny would shift perfectly now if it had been serviced much sooner.

If anyone who reads this would like some of the links to the resources that I used just PM me.

If however, you are a person who wants to tell me that I am wrong or that people should "always follow" manufacturer recommendations or whatever. Just keep that shit to yourself. If you do not agree with me then you have the choice to ignore what I have posted. If there are other people on here who have PERSONALLY rebuilt their Mechatronic. I am sure that their findings will be similar to mine. Good luck with all of you E90 issues!

[rich_mane]

I'm very interested to see what resources you used for your mechatronics rebuild. I've been looking into doing this myself. I'll send you a PM.

[dannyle27]

Hmm... I need to get it sorted out. Max at NE autobahn said it could be multiple things

1. servicing the transmission as you stated
2. TCU flash
3. Back end flash- too much load
4. Sorting out my tune
5. Transmission... clutch packs??

I flashed back to the BMS pump flash from the PI/TBI one and got a smooth run on map 7. Map 3 was all over the place =( felt like there was a limiter at 5k rpm

What oil did you use for your tranny? OEM bmw or something better?

[Cory S]

I'll be using Redline D4 when it comes in on Wednesday.

[04gto]

One very important item I did forget to mention below, the tune you choose can make a huge difference in the shift quality of the trans. I have used over 40 different tunes now and I take written notes of how each performs. The OTS MHD map that seems to get along best with my tranny is the V5 maps (current is E40). However as a pre-release beta tester of the V6 maps, I can say that with a custom map you could do even better. Ken Atkinson sent me several maps during V6 Beta testing that worked very nicely and were even more powerful. I have found that leaving the "linear throttle" un-checked and checking the "deactivate kickdown" switch works great. I switch to sport and switch gears manually and it shifts very smartly. Mind you, this is my car with my transmission, my tune and my very aggressive driving style. I used the OEM fluid from CTS to refill my tranny after service. It has been about 15k miles since I performed my service, so I will do it again in 35 k miles.

Originally Posted by dannyle27

Hmm... I need to get it sorted out. Max at NE autobahn said it could be multiple things

1. servicing the transmission as you stated
2. TCU flash
3. Back end flash- too much load
4. Sorting out my tune
5. Transmission... clutch packs??

I flashed back to the BMS pump flash from the PI/TBI one and got a smooth run on map 7. Map 3 was all over the place =( felt like there was a limiter at 5k rpm

What oil did you use for your tranny? OEM bmw or something better?

[dannyle27]

I know you read my facebook message.

Originally Posted by Cory S

I'll be using Redline D4 when it comes in on Wednesday.

[dannyle27]

N55 man... We don't have the luxuries of MHD

Originally Posted by 04gto

One very important item I did forget to mention below, the tune you choose can make a huge difference in the shift quality of the trans. I have used over 40 different tunes now and I take written notes of how each performs. The OTS MHD map that seems to get along best with my tranny is the V5 maps (current is E40). However as a pre-release beta tester of the V6 maps, I can say that with a custom map you could do even better. Ken Atkinson sent me several maps during V6 Beta testing that worked very nicely and were even more powerful. I have found that leaving the "linear throttle" un-checked and checking the "deactivate kickdown" switch works great. I switch to sport and switch gears manually and it shifts very smartly. Mind you, this is my car with my transmission, my tune and my very aggressive driving style. I used the OEM fluid from CTS to refill my tranny after service. It has been about 15k miles since I performed my service, so I will do it again in 35 k miles.

[04gto]

Originally Posted by dannyle27

N55 man... We don't have the luxuries of MHD

soon you will have the luxury of MHD.

[dannyle27]

Do you promise?

Originally Posted by 04gto

soon you will have the luxury of MHD.

[04gto]

Originally Posted by dannyle27

Do you promise?

Pinky swear

[kong24680]

Originally Posted by 04gto

I never experienced any slipping in my trans until I went over about 420 torque at the wheels. My car is 2008 with 79k miles. Car had only 40k when I bought it 2 years ago in excellent condition. After I went FBO (60k miles)and started running e40 etc I got horrible slipping, gear hunting, failed shifts and tranny limp mode. After a few days I could not get on it at all without the gear symbol appearing on the dash. I started doing a bunch of reading. ZF technical manuals, troubleshoting manuals and endless online forum searches.

What I discovered:
1. Online forums can be an amazing source of knowledge. Save you a ton of time. But when it comes to very technical\complicated things like an auto transmission, the info is only good if you know what info to ignore. The only way to know what to ignore is to have an existing knowledge of the subject. 95% of the online "advice" on the subject of our transmissions are completely wrong.
2. The 100k (or whatever) recommended service for our transmissions is BS. If you drive your car hard at all, or drive in a lot of stop and go traffic or live in an extreme climate, it should be changed at about 40 or 50k miles. If you take apart your Mechatronic and rebuild it like I did, you will understand the before and after benefits of this.

I have been working on cars since I was about 17 years old (40 now). I have rebuilt a few engines big (Chevy 454) and small (Honda 125) but I have never touched the internals of an auto tranny before.

I ordered all the parts to rebuild the Mechatronic unit from CTS. Solinoids, Zip kit, sleeve, fluid, pan, filter etc.

The results? Amazing difference! Shifting was super crisp and smooth, no gear hunting, no limp mode.

Slipping? If I drive it agressively in auto (sport or regular) it will still sometimes slip between 4th and 5th. But if I shift it manually there is zero slipping.

Why is it still slipping? Based on all my reading. (Again from technical service manuals or materials written by professional mechanics or the transmission manufacturer). There was some damage already done to the clutches between 4th and 5th gear.

I am certain the tranny would shift perfectly now if it had been serviced much sooner.

If anyone who reads this would like some of the links to the resources that I used just PM me.

If however, you are a person who wants to tell me that I am wrong or that people should "always follow" manufacturer recommendations or whatever. Just keep that shit to yourself. If you do not agree with me then you have the choice to ignore what I have posted. If there are other people on here who have PERSONALLY rebuilt their Mechatronic. I am sure that their findings will be similar to mine. Good luck with all of you E90 issues!

Really appreciate the detailed post. I'm actually having the same problem with my 4th to 5th gear shift on load. There is a very bad grinding/ hesitation between between my 4th to 5th gear shift that's got me very concerned. I devices my transmission around 10k miles ago, but the problem is still persisting. Is there any other possible fix other than replacing the transmission?

[JETmn]

Originally Posted by 04gto

Pinky swear

That makes me giddy! MHD would be amazing, I sure hope it happens. It is looking like PS2 and PI this fall/winter.