transmission question

[cavx5]

hi everyone..tried to reseach this but could not really find anything...exactly what is the mechatronics unit in the tranny and what are symptoms if it is going bad or if it is bad..i am having some ongoing tranny problems with my x...2005 x 4.4 with 24k miles..thanks rob

[wullaby]

wow only 24K miles, not good! You have shifting problems, rear slamming, long rpms before shifting? You should put down what your symptoms are that would help out others to see if they can help...

[cavx5]

hi wullaby...if you search by member id you can read all the tranny posts..its not that many but briefly hard 2 to 1 shift while slowing..just before coming to A complete stop feel several jerking sensations..and if i use the car for a few hours then i let it sit for a few hours then drive away it wont get out of first gear until the tranny warms up usually about a minute in hot weather and a little longer in cold weather..in the winter both situations get worse...recently had tranny totally reflashed situations got slightly better but still exist and know i occasionally get a slight rearend thump after i stop which i never had before..rob

[X5Sport]

The 'Mechatronics Uint' is basically the tranny's brain. It holds details of the type of vehicle and the gearbox shift pattern 'map' in the same way that the ECU holds the engine's performance map.

It also has various hydraulic control valves and solenoids that provide the feeds to the clutches etc inside the tranny that are used to actually command each shift change.

It also communicates with the engine's control systems to try to ensure smooth shifts during warm-up, normal driving and 'Sport' mode driving. I think it also holds the 'adaption' data for the drivers own style to improve/refine the shift patterns.

It sits in the bottom of the tranny just inside the oil pan. It's also expensive if it fails. Mine was £1200 plus fitting and was replaced following a catastrophic failure in the torque comverter which wiped the tranny and MU out - the MU due to metal fragments in the oil damaging the solenoids and hydraulics.

[thecount123]

Sorry OT post. Is the tranny prob for manual trasmission x5 only? And not for automatic? Thanks

[X5Sport]

Auto only. Not aware of any probs with the manual versions. They're pretty rare compared to the auto unit (certainly in the UK anyway).

[4MoJoe]

Mine was replaced last October (ish) I believe at a cost of just over $4,000 (parts & labor). I would be driving between 35 and 40 and the car would have these little bumps like somebody hit the brakes real hard and then let off - felt like I was getting hit or something. Fortunately I had my extended warranty and only paid $100.

[thecount123]

Thanks

Originally Posted by X5Sport

Auto only. Not aware of any probs with the manual versions. They're pretty rare compared to the auto unit (certainly in the UK anyway).