txag_530i

I'm not even sure that you can buy the individual solenoids.

KyleB

Believe it or not, you can.

ranger530i

KyleB but the only problem isnt the guibo its multiple issues they were saying but the main problem is the 2-1 jolt and also random transmission failsafe usually when i try to overtake a vehicle on the highway

KyleB

The 2-1 downshift 'jolt' was a common complaint with 6HPXX gearboxes. most were alleviated by resetting adaptations.

the transmission failsafe you're getting, and the conditions you describe, are typical of cars that are having valve body problems. i.e., solenoids.

guibos are made of rubber, and they just wear out.

What exactly it's going to take to fix your car I can't say. Maybe a set of solenoids will do the trick provided you haven't been driving around like this for a prolonged period of time. Every time you see that failsafe warning, it means the transmission is slipping in one of the clutches. If you let it do that for too long (and it doesn't take long at ALL), you will 100% be rebuilding and or replacing your transmission.

good luck.

txag_530i

If you want to try and pin-point the solenoids as the culprit, then drive around in "Sport" mode all of the time. (Move the gear shift back to Drive and then push to the left.) I did this and never received the transmission failsafe message again. This further reinforced my opinion that the solenoids were not actuating correctly. I replaced the solenoids over the weekend and have put 100 miles on the car in the normal drive mode and have not yet received a transmission error message. Prior to the solenoid change I was getting the failsafe warning a lot, particularly while trying to accelerate.

I need to put a lot more miles on the car before being completely satisfied with the results, but so far, so good. The transmission is shifting well, and I no longer get the 2-1 bump when coming to a stop.

Tkarrde

Just a quick update I've now put 1000+ miles on the car without incident. I am going to leave it alone for now.

ranger530i

Does the 25sec trick truly reset adaptations? Bcause i still recieved the jolt after doing it. Also when overtaking a vehicle its really embarrasing when youre zooming by and all of a sudden your engine revs high and you get the dreaded ding dong and the flash of red gears on your idrive screen and drop way back plus its pretty dangerous too! So, I'm assuming your advice is to replace the solenoids first before replacing the transmission? Is the guibo hard to replace? I really appreciate all your help because you guys so far have saved me a lot of money on this forum! sorry for asking so many questions
I have done that too while in Sport mode the car shifts fine its just the normal mode that concerns me. I dont use sport a lot mostly to save on the fuel. I drive a lot on TX-7 so if youre familar with around there then you understand the urge to want to just fly down the road! but i cant do that with failsafe messages.... where did you buy your set of solenoids? Im hoping this is the answer!

txag_530i

The "25-second trick" does not work. You need to reset the transmission adaptations using INPA or other software.

Yes, replace the solenoids (and seals!) before replacing the transmission.

I purchased the solenoids at thectsc.com.

I purchased the seals at pelicanparts.com

I did the work in my garage with the car on jackstands. The worst part of the job for me was both the transmission fluid getting everywhere (buy lots of Oil-Dri pads) and removing the Mechtronics seal. There's just not a lot of room to get that seal out, especially lying on your back and only being able to use one hand.

ranger530i

Thanks for the info txag 530i and KyleB! I will be doing this soon! Lol solenoids are more expensive than i thought they would be but its sure a lot cheaper than a whole new transmission! Thanks again to everyone!!

john4all

Really good info, guys. Thanks for the time and effort!

I just have one question as I get ready to replace solenoids on my 6HP21 (335i). Has anyone experienced issues in the 2nd - 3rd upshift (delayed, rough shifts)? Or perhaps a hesitation/bump on the tail end of the 3rd gear just before upshifting to 4th?

I have the tell-tale *thump* on the 2nd - 1st downshift, but the others are a little less common it seems. Klaus at TheCTSC mentioned it could be a worn brass bushing, but I'm hoping someone here has experienced these issues and resolved them without a transmission rebuild.

Thanks in advance for any information you can provide!