4.8is - Gear shift issue - only from 3rd to 4th

[pkortun]

Hello,
I'm new to this forum but not new to BMW World with 2001 750iL and 2000 M5. We recently bought 2005 x5 4.8is with 130k miles for my wife and still very happy with this wonderful car (especially my wife who hates driving m5 and doesn't "feel" 750iL). But we have one issue with X, which makes it imperfect and I cannot find anything on this and other forums.
Long story short, transmission works well 99% of its time - upshifts and downshifts very smooth in regular D mode and slightly stiffer in Sport and Manual mode. There are no downshift kicks reported on this and other forums. However, from time to time it acts weird during acceleration when shifting to (or from) one specific gear, I believe to 4th from 3rd. Hard to describe it - car slows down initially and then shifts very harsh. It's like not synchronized clutch engagement during gear shift by using a manual tranny analogue. I guess either a torque converter is not engaged properly during the shift, or tranny has problem going from previously activated gear into the next one. Perhaps, pressure is building / releasing slower than needed. This also supports 2 second delay when engaging the reverse.

Everything is fine after that with other upper gears - it shift up and down with no issues. It never happened when the X is cold only when the car at operating temperature (in contrast to majority of X5 tranny issues). It always happens at low load and some specific gear. Never had issues at full throttle. We checked error codes - nothing. I check voltage - 12.4V / 14.4 with engine off/on. Engine oil temperature doesn't exceed 210F and I hope tranny as well since they seem to share the cooling line (but radiators are separated). Tranny cooling lines don't exceed 185F (measured with IR gun). BMW dealer couldn't find anything and suggested... you know what. I changed the tranny fluid twice with ZF LifeGuard6 fluid following the right procedure. Hard to say whether it helped but the issue still comes from time to time.

Thinking what to do next, I'm almost ready to replace the solenoids
Solenoid Kit - 6H19/26/32 M-shift
since I'm very positive it's one of those guys doesn't release or doesn't build up pressure properly. I wanted to ask you guys whether I'm on the right track and whether there is a way to check performance of those solenoids. I apologize for such long post - just need an advice of experienced folks since I never dealt with tranny rebuilt (although do all the work with M5 and 750IL myself). I also hope this post will be helpful for others with similar issue in future. Thank you guys in advanced.

p.s. attached pictures show small coding of metal shavings on the filter and original tranny fluid when I changed it.

[bastereo]

I wouldn't be worried at all by the stuff in your transmission pan. Did it have a magnet or a few in the pan?
But the pan is pretty good for over 100k and you have to assume it was never serviced before.

I couldn't open the link on my phone. So i don't know what you are looking into. But I would think about getting a new valve body if you are going to do the solenoid pack.
There are lots of people with valve body issues and it should include the solenoids.

Sent from my SGH-i917 using Board Express

[renevatio]

Similar issue with my '06 4.8is. Both engine and transmission needed a software update and I've not experienced the issue again. I'm a bit skeptical but the proof's been in the driving so far. So, my suggestion is check and update your software, I thought it would be a good idea for me even if I ended up replacing the mechatronics unit and or TC. Good luck.

R

[pkortun]

Originally Posted by bastereo

I wouldn't be worried at all by the stuff in your transmission pan. Did it have a magnet or a few in the pan?
But the pan is pretty good for over 100k and you have to assume it was never serviced before.

I couldn't open the link on my phone. So i don't know what you are looking into. But I would think about getting a new valve body if you are going to do the solenoid pack.
There are lots of people with valve body issues and it should include the solenoids.

Sent from my SGH-i917 using Board Express

Yes, there were two round magnets visible on the pictures of my original post. They have more shavings.

What could go wrong with the valve body except those solenoids? Are there any narrow channels/filters that could be clogged with the metal shaving I found on the transmission pan?

And yes, I just scheduled a next appointment with BMW to flash the software on Wednesday. They said it can take up to a day. Wow! If they reserve enough time to learn how to do the flash, it disappoints me.

By the way, is there any downside of the transmission overfilling? I was focusing to topping it off as soon as quick as possible, so it could be too cold (between 25-35C) when I closed the plug.

[pkortun]

well, the dealer checked the car again, didn't find any codes, checked the fluid level and updated the engine and transmission software. I noticed a minor improvement of upshifting in Sport and Manual modes - it became very smooth. However, the jerking between 3rd and 4th gear wasn't fixed. Dealer claimed they did notice that. However, if they would, they can only advice to replace the whole transmission. So, what's next for me? Replacement of solenoids or the whole valve body unit? Any suggestions?

[TwinsPoppa]

Originally Posted by pkortun

well, the dealer checked the car again, didn't find any codes, checked the fluid level and updated the engine and transmission software. I noticed a minor improvement of upshifting in Sport and Manual modes - it became very smooth. However, the jerking between 3rd and 4th gear wasn't fixed. Dealer claimed they did notice that. However, if they would, they can only advice to replace the whole transmission. So, what's next for me? Replacement of solenoids or the whole valve body unit? Any suggestions?

Valvebody/Mechatronic problems are common. IIRC, it has to do with o-rings and maybe needles. You can do a search and read up on it. Dealer will not rebuild tranny. They can only offer to sell & install a remanufactured (not rebuilt) tranny.

Others may chime in with things to try but ultimately you might just have to take it to a reputable transmission shop for a proper diagnosis. It would be very helpful if they can reproduce the problem. It may be a combination of torque converter, valve body and/or other things.

If you are a person that leans towards rebuilding vs replacing the transmission, its critical that the shop is familiar with working on ZF transmissions or have access to a proper tech. From my experience looking into rebuilding, most shops don't have a knowledgeable tech - they usually have to farm it out.

Rebuilding will save you money from just dropping a remanufactured but may cost you some time. Also, rebuilding may save you the headache of the mechatronic trans module not having to be recoded to your vehicle.

Good luck and I will follow this thread with interest on how it all concludes.

[SlickGT1]

Subscribed. Everyone including OP seems to be on the right track. 130k miles is not bad on original trans and oil.

We need some trans experts to chime in.

[eyeiieye]

I will follow this thread with interest

[pkortun]

just want to update you with my story. It may help others. Just to remind, our X5 jerks while shifting from 3 to 4 when tranny is at operating temperature. There was a 2-3 second delay when engaging Reverse.

So... I replaced the whole set of solenoids, which actually drive gears. Solenoid kit (and LG6 + filter) was bought here:
Solenoid Kit - 6H19/26/32 M-shift
In order to replace solenoids, I had to remove the entire mechatronic unit first:
http://www.zftranspart.com/images/custom/mecha.pdf
or
BMW TIS - 24 34 561 Replacing mechatronics (GA6HP26Z/6HP32Z)

Results (so far):
1. Shifting from 3 to 4 is very smooth now regardless whether the tranny is cold or hot (positive)
2. There is no delay when switching to reverse any more (positive)
3. Shifting from 1 to 2 is much harder than it used to be with old solenoids (negative)

So, new solenoids definitely helped but the new issue is introduced. Temporarily I hope. I will double check the fluid level tomorrow - perhaps some fluid filled drained volumes and fluid level is low now.

If it won't help, perhaps I should reset the tranny with computer at dealership (I did the reset with accelerator to floor for 30 sec)

[SlickGT1]

That 30 sec pedal to floor is bs. You need to reset adaptations with GT1/DIS.

Have you had your trans software updated ever? It might be time to bite the bullet and pay the stealer.