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harrychiu012 harrychiu012 is offline
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Default Auto Tranny Issue - 01-13-2016, 11:44 PM

Wanted to get some feedback with people with Auto transmission that have tranny issue.
Backgound info: 08 N54 FBO, RB inlets, Walboro 450, running JB4/MHD BEF E60. Car has 110K miles and is Alpina flash since 75K.

After flashing the car to E60 flash running on map7, I had two incident where the tranny slip:
1st time: Disabled the 2nd gear Max boost on JB4 and went WOT from 2nd to 3rd, and got a transmission malfunction. Now I limit the 2nd gear max boost at 12 and is okay. Doesn't shift as smooth, but no slip since.
2nd time: From 5th gear downshifted to 4th and got the same code.

I recently did a transmission oil drain and filled, and changed the oil pan/filter, topped with ZF transmission oil.

Is my only option to remedy this problem is to swap a transmission?
I've read that changing the valve body mechatronic solenoids help with rough shift, but does it help when the tranny is slipping at high power (high torque)?

I most likely will have to tune down the flash to much milder one until i can figure something out. Transmission swap is something I really don't want to do, parts and labor are going to be costly. The car drives fine in normal daily driving condition, but it sucks not being able to push the car that I wanted to.

Any suggestion or feedback are welcome.
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E92 420 E92 420 is offline
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Default 01-14-2016, 03:48 AM

https://sayyarti.wordpress.com/2015/...ission-issues/

Have a read this is good info and I'm sure it can help with your problem


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Race8877 Race8877 is offline
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Default 01-14-2016, 03:50 PM

PURE TURBOS:


Insider ZF knowledge:

Replace your Front Stator bushing with the Omega upgraded part:

http://www.omegamachine.com/db/ZF6HP...hing%20kit.asp

The front stator bushing is what causes most 4th, 5th, and 6th gear problems. It can be done without disassembling the whole trans.

The front stator bushing is not only a shaft support bushing, but more importantly: seals oil pressure to the E clutch (4,5,6). The OE ZF bushing is inferior, the bearing babbitt fails especially with increased torque.

Our shop 135i OE bushing was worn out, with a measured clearance of .008", OE spec is .0015". The excessive wear bleeds off the much needed engagement pressure for the E clutch.

Most ZF6HP21 trans problems are caused by this bushing. But of course, trans shops won't tell you this.
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Default 01-14-2016, 03:52 PM

Both a MHD flash only tune (MHD maps or custom tune) and a JB4 + flash backend (the BMS MHD maps) will increase reported torque to max the trans pressure. Unlike the stock map and the bb flash.


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Default 01-14-2016, 03:58 PM

Originally Posted by AUbeast86
Here's what I'm going to do to my 2 transmissions...

Teardown and inspection:
https://www.youtube.com/watch?v=P7yJoOH7CZk

Valvebody overhaul:
https://www.youtube.com/watch?v=ld3Dlu4kp_g

Bushing Upgrade PT1:
https://www.youtube.com/watch?v=ld3Dlu4kp_g

Bushing Upgrade PT2:
https://www.youtube.com/watch?v=szG2ApdqDiw

I've also been in contact with a company that provides upgraded material for the clutch packs that I will install at the same time.
It's easy to see in the videos that this is a clutch based transmission which makes it very important to control the heat of the ATF across the clutch packs since it is used to cool them. ATF has 2 functions; 1) Lubrication and 2) Cooling.

I spoke with several techs yesterday, including one at Omega Machine, and they all agree heat management is the first line of defense in protecting a transmission, or anything else for that matter (like this even needs to be discussed). If you can't control the heat, there's really no point in upgrading the internals because you're just going to smoke them again, especially since these bushings are not only used as support surfaces they are also used as seals.

He went on to explain why the OEM bushings are failing and it's simply due to the manufacturing process. These bushings are mass produced in a way that makes it difficult to hold the machining tolerances required to maintain the higher pressures. The upgraded bushings are CNC machined out of bronze, enabling them to achieve much tighter tolerances. This provides a much better seal.

The critical path to mechanical failure is this...heat smokes the clutch packs -> the clutch packs release particulate that wears the bushing surfaces -> the worn bushings bleed pressure off -> pressure loss results in slipped gears and this perpetuates the cycle. The clutch particulate also cloggs up the solenoids in the valve body exacerbating the issue.

So, I figure these internal upgrades along with my ATF cooler is absolutely everything I can do mechanically that will hopefully let me reliably float around the 600whp level. I fully understand the importance of gaining access and control of the TCM but we are not there yet. We'll see...

management is crucial of course, BUT i think heat is the most vital aspect of a trans, a proper cooler would fix a lot of problems.


--------------------------------------------------------------------------------

07 335 E90 AT: Single Turbo currently in the process..... JP Works Manifold, Precision 6266, & AD Engineering Port Injection/Split Second being installed as we speak.
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harrychiu012 harrychiu012 is offline
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Default 01-14-2016, 11:13 PM

Update: I went to see my tuner today regarding the tranny issue. He flashed my car with a base e50 bin file for MHD backend...
We disabled 1st and 2nd gear max boost limit, and doesn't matter how hard we pushed the car with traction control off, the tranny did not slip at all.

I think it was the custom e60 map that i was running that was causing the issue.
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Default Rumble in the tranny jungle - 03-17-2016, 04:18 PM

Automatic tranny: For a long time now, when taking off from a stop, I get a noticeable but not too harsh shuttering and sort of a non-audible grinding feeling at about 1500 to 2100 RPMs, and it then clears up and behaves normally, until I start off again.

I initially thought it was something to do with the Quaife LSD, but ruled it out after talking to Quaife, and performing a wheel rotation test. Plus, after more than 7,000 installs of this model LSD, he said, there hasn't been any problems, and if there were, it wouldn't act in that manner.

I'm left to assume something is going on inside the tranny. It doesn't slip between shifts. As most of you know I've thrashed this tranny a lot over it's 49k life. Major foot-brake launches with sticky tires and close to 500 horses.

Any suggestions? I can't afford a new tranny at this point in my life!


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