171k miles - Zf6 auto box service

[BMW_Fan2020]

Hi all
My brand-new 330d has travelled 171,000 miles and there is no record of a transmission service. I've conducted considerable investigation and spoken with three or four local specialists, both BMW and auto box specialists. My choices are:

1) Have the filter, valve body, and four seals serviced immediately.
2) receive the above maintenance as well as a gearbox cleanse.
3) Do nothing, as there is currently no issue, and save the £450 saved on the service for a recon box in the future.

I would like an XHP stage 2 or 3 flash on it because I prefer the quicker, smoother shifts; however, given the mileage and uncertain service history of the gearbox, am I asking for trouble?

thank you

[Megan_Wilson88]

With that mileage, servicing the box is always a gamble; it's essentially a coin flip. You might have no problems, but you could also be unfortunate and the new oil dislodges some material, causing a problem.

on 171k I wouldn't risk flashing the box if it were me.

[James_Rover99]

Stay away from xhp stage 3 unless you want problems, or get it serviced,no need for a flush,it needs doing twice to get every bit of old oil out,quitebexpensive as new oil each time,me id just run as is,but if you're keeping it, get it done.
M4

[Jacob_Evans2001]

When I originally acquired the vehicle, I did mine at 167 thousand miles.
I have no clue whether it has ever been done, but the fluid that was extracted seemed unhealthy; it was a dark brown or nearly black colour, and the box became and continues to become extremely smooth after it was done.

[BMW_Fan2020]

With that mileage, servicing the box is always a gamble; it's essentially a coin flip. You might have no problems, but you could also be unfortunate and the new oil dislodges some material, causing a problem.

on 171k I wouldn't risk flashing the box if it were me.

Thanks Johnny that’s the dilemma. Rest of the car looks and drives like a 70k miler and I want to keep it. Just worried about dislodging some debris.

[BMW_Fan2020]

Stay away from xhp stage 3 unless you want problems, or get it serviced,no need for a flush,it needs doing twice to get every bit of old oil out,quitebexpensive as new oil each time,me id just run as is,but if you're keeping it, get it done.
M4

Regards, Rasa. Would an XHP (perhaps stage 2) be safe if I had the box serviced and everything was OK for a few months afterward?
Local BM expert recommended a flush, however I believe it was more of an excuse since they conveniently lacked a flushing machine.
How many miles or how long should pass between the two oil changes if you claim that the box requires two oil changes to remove all of the oil?
Would you replace the seal kit after the first flush or after the second? How are the solenoids doing? (I apologise for all the questions; I haven't driven a BMW in a long time.)