zank
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- Sep 24, 2007
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Here I would like to share with you about my experience (E39, 528) on the transmission. It is an expensive experience, so I hope it would benefit all of you, especially those just about to get a BMW and intend to change gear oil. .Got mine a few months ago, like any "smart" guy in town, my first action is change all oils (gear, brake, engine, you name it...)After a few months, I have this problem, the engine will slack or slipping when crusing on RPM1500, yes you will ask why running on 1500 rpm? that is the speed when you are on gear 4 or 5 in KL/PJ traffic when running 60-100 KM/H mostly, the car rpm will drop from 1500 to 1200 and then back to 1500 again, this will keep happening every few seconds, unless you floor to high rpm/speed. This problem also not happening when you switch to S/M mode. After consult many mechanics and specialist, as usual you will hear all kind of different opinions (because everyone is uniques, that is the beauty of human being, there are never the same, that is why corporate management comes out with Managing people training..heheh). Even so call Expert in town will not be able to identify what is the cause, yes included the sifu in Sapura Auto..). The computer Diagnosis will not be able to detect this kind of mechanical fault. One of the E60 owners also experience the similar symptom but his fixed with complete change of ECU, and lucky his car is under warranty. E60 could have this problem when the ECU failed to provide a good oxygen ratio mixture, and the fault will eventually detected by Computer/GT1.Finally I met one of the Gearbox specialist in town, who repair/recond gearbox more than other service car, it is true no joke, his shop pstacked with more than a few hundred gearboxes, he convinces me that no charges if the problem not solved, and he said 110% torque converter. Now the interesting part: Oil Change.This topics has been discussed thousand of times on forum whether one should change oil or not, though BMW said Life time, and most said life time = 100,000KM. According to this Gearbox sifu, if you never change the gear oil before, and if the mileage has been over 70K/100K km mileage, than you might not want to change it, or if you do change, be prepared for some problem, the reason is the new gear oil with fresh additives will act like a cleaning agents to eat up all the dirt inside the gearbox/TC, and if the TC/Gearbox clutches condition is not good anymore due to never change oil over 100,000 KM, then this new reaction will accelerate the already worn up parts, and cause the failures, but if you have been changing every 30-40K, then it is good and you should keep doing it. But if you never change and will not want to change, then just drive until the gearbox is kaput, that is why BMW said lifetime, by the time you hit 150,000KM, you are expected to replace a new gearbox, simple!I have the privileage to see the TC being cut into half and see what is exactly went wrong inside, but this sifu is not happy, and insist I do a complete Gearbox service, meaning to dismantle complete everything and do a good cleaning. There he found a few more clutch plates eaten up and require replacement. Believe it or not, the time it takes from dismantle, services, change parts, assemble back and all done within 2.5 hours, right in front of my eyes. Why the problem not happening when i switch to M/S, it is because the locking system by-passed the TC, and straight into the gearbox, that is why you get more immediate torque for overtaking, but it is not best practice for normal drive as it place lockinng burden on the gearbox rather than TC, with more fuel consumption and also which eventually worn up your clutch plates inside gearbox faster. A recond/used gearbox will cost you RM8-10K, even then you do not know what is the condition, so get your gearbox serviced every 100,000KM will probably extend the life time for another 10 years. Hopefully my painful experience is benefiting you.
