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I tried all the "easy" things to resolve my "Kick-Down" gear shifting problems with my 2005 Super V8 including coils, rear ABS sensors, leak checking the intake system, replacing the battery, cleaning the ECU connector and replacing all 4 tires. No luck - - I would have to open the gearbox. I got everything I needed (bridge seal, connector sleeve, mechatronic seals, Oil change kit, and a set of new solenoids) from https://www.thectsc.com/ who were fast and helpful. I also decided to replace the transmission cooler lines which were weeping slightly at the rubber sections and I found them for around $200.
Replacing the cooler lines is quite difficult unless there is some trick that I never figured out. I would write up a detailed procedure but honestly I don’t feel like I have anything to say that a competent mechanic couldn’t figure out on their own. Snaking the lines between the front subframe and the bottom of the engine is impossible on my car without bending the lines as you go and then re-straightening them in place. Accessing the lower fitting on the radiator is also incredibly difficult (yes, the air box was out). There are radiator hoses blocking it from the top and subframe, sway bar, power steering and A/C hoses blocking it from the bottom. (I recruited the scrawny kid from up the street to reach in there but even he was thwarted.) I finally was able to access the fitting nut from underneath by putting a 19mm combination wrench up through a tiny slot just behind the radiator. I was able to get about 10 degrees of rotation before I had to take the wrench all the way out of the slot to flip it, and then peer up through the slot to get it back on the nut. Needless to say this procedure is tedious, but nothing is so awful that it can’t get worse and soon it did. The wrench slipped out of my hand and landed square on the corner of my eye socket. I had a black eye for 5 days. (for reference grab a vintage Craftsman 19mm combination wrench and imagine it dropping vertically on your face)
One good idea I did have was to fasten the protective covers onto the fitting ends so the o-rings wouldn’t get damaged during the aggressive snaking that’s required. All told the cooler lines alone took 8 days if you include time out for head scratching, combing clumps of grease out of my hair, and waiting for the skin on my forearms to grow back. Unless your lines are pouring out fluid, just leave them for the next owner. BTW, I suppose I could have drained the engine coolant, disconnected the hoses and engine mounts and jacked up the engine to make room to snake the transmission lines in but…..no.
The work on the gearbox itself went very smoothly and was quite fun. Don B and others on this forum have posted all you need to know to get the pan off and replace the connector sleeve. The CTSC website contains excellent instructions for removing the mechatronic and replacing the seals and solenoids. There are also many BMW related videos online that show how to do this and I think every ZF gearbox will eventually need to have it’s mechatronic seals replaced simply due to age. My opinion is if you are taking the pan off of a 15 year old gearbox, you should at least replace the seals and if you’re having any shifting symptoms, the solenoids also.
Over the two weeks of the project I collected 8 L of transmission fluid which, incidentally had been changed 15k miles ago so was in good shape. It drips out very slowly. I used an industrial temperature probe shoved in the fill hole to monitor the fluid temp while we waited to reach the required fill temperature. It took 8.5 L and the capacity for supercharged cars is about 10 so I figured flushing was not necessary since at least 80% of the oil was replaced.
I have an appointment at the dealer in 2 weeks to have the adaptations cleared and the TCM software updated to the latest (final) release. In the meantime the shifting behavior of the gearbox has changed noticeably in the lower 3 gears. It is much more abrupt which leads me to believe that more pressure is reaching the clutch actuators rather than leaking past the seals. I have not tried kicking it down yet because the adaptations are wrong, and also because if it still pops into neutral I’m out of ideas.
Hi,
i replaced the oil cooler lines too this week because i was tired of the leaking flexible hoses.
So after that i can say life is much easier if you loosen the motor mounts and lift the engine a few centimeters. Even if you do that the job remains a pita but you dont have to bend the lines more than a few degrees. In addition to that i removed the left hand lambda monitoring sond and loosend the steering gear to gain a few more inches.
And without having seen your post i had the same idea regarding the protective covers, after five times of picking them up from the ground.
Onother good idea is having a break with a cup of coffe to calm down sometimes, if dispair tries to get upper hand. And fortunately i left out the black eye.....
Regards, Fritz
Congratulations to you man. It's not an easy job and I hope I never have to deal with that one again. Can you lift up the engine without disconnecting the cooling hoses? I am very reluctant to put stress on old plastic radiator fittings!
I had forgotten about that black eye, thanks for reminding me lol
Taking a break is the most important and often used tool in my box!
Hi Jeff,
actually were talking about 1 to 1.5 inch of lifting the engine and all the fittings and hoses survived without damages. despite of that youre right , it is helpful to act very careful that way. i felt in love with the method recently while trying to get acces to the upper starter bolt....
Jeff, my car is an X358 from 12/2008, 4.2 ltr N/A, two previous owners, 70 k miles, black on black.
I suppose the question is at what mileage you' ll have to expect starter issues. I'm not able to answer that question, because i had no starter issues. It was just a job of preventive maintenance because i often travel abroad and i dont like to run aground with such issues.
I used the repair kit containing switching contacts and the plunger for the solenoid. Its about 20 bucks and you'll have peace til the end of time...;-)
Gearbox service and cooling lines replacement
