Quote:
Originally Posted by mainbearing
From Sonnax's website ( https://www.sonnax.com/parts/3505-zip-kit), the kit reduces critical oil circuit pressure losses. And the symptoms include:
Burnt clutches
Delayed engagement
3-4 Bump
Inadequate lubrication
Low pressure
Slips & flares
Soft shifts
TCC apply & release concerns
TCC codes
There may not be a down side for not installing it if you do not feel the problems mentioned above in shifting. However, with the problem description I would think the kit will make the transmission last longer if you enjoy this car and plan to keep it around for a while, particularly if you are dropping and disassembling the valve body to change out the hardened leaky seals which is where most of the work is at, IMO.
There is a pressure regulator valve you will not be able to get to without dropping the transmission however, but at least the rest will get updated.
As far as your skipped gears in manual mode, one possibility would be the computer will try to select the gear suitable for the speed and may be overriding. The other is that the pressure switches helps the computer decide shift points and shift calibrations, and may be thinking 4th would be the right gear then. I am not sure if those are actually the problems, just guessing.
Yup, overall the 6L45 is just not a good transmission compared to the ZF 6HP. I guess BMW had to cut cost somewhere, including using cheap plastics in the cabin.  IMO the plastics in the newer ones are even worse. |
My theory for the skipped gear in manual mode is-
There is some what of a delay when shifting in manual mode, when you up or down shift its not instantaneous like a DCT or a new trans. I'm thinking that when I attempt to go into 3rd, I'm shifting a half second too late. So basically it shifts twice... if that makes sense.