98 bmw 540i transmission

[william3742]

I notice that in 20 degree weather when i first start my car and put it in drive it seems to take a longer time to shift in cold weather than in warm weather. After a couple of minutes everything seems to be fine. Does the transmission have a solenoid or some type of relay that could cause this to happen?


This is on a 1998 BMW 540I
4.4 - V8 ENGINE
Auto Trans
128000 Miles
Thanks

[brettski]

If the oil in the gearbox has never been changed, its probably time to do it. Take it to a specialist shop that get the old oil out of the torque converter and the pan, and make sure they use the right fluid and genuine filter. Get them to cut the old filter open so you can see if there is any abnormal amount of metal in it.
Good luck

[william3742]

Thanks for advice i had read a lot of post where other owners were talking about changeing the oil without getting it out of the torque converter, and then doing it again after a short time. This made no scence to me. They were saying that there was no way to get the oil out of converter. I read someware that NAPA made the only oil remover machine that would remove the oil from the converter. I wish i had saved that web site.
I will try to find out from BMW service dept. about this. Have a good day.
Thanks

[brettski]

Hunt around your local Auto Trans service shops because some of them will have the equipment to drain the torque converter as well, they get around 90-95% of the oil out rather than 40-50% that you get through draining the pan. It shouldn't cost you too much either. BMW don't like to change the auto fluids claiming that the grearbox is sealed for life, which in effect is true, because when the gearbox fails, they put on a new "sealed for life" gear box. By changing the oil regularly 40,000 - 50,000 miles you keep the oil fresh and remove the metal particles that end up in the system through normal use, thereby extending the life span of the gearbox. There are indeed two lines of thought about this approach, but speaking with ZF (one of the manufacturers) they agree that regular maintenance is the best way to extend the life of the gear box and retain the "normal" operation for as long as possible.

[william3742]

Thanks for your time you spent on getting this info. You have been very helpful. I will follow up on checking for a shop that has the equipment to drain the torque converter'
William

[brettski]

It really isn't that hard to drain the torque converter, you can simply remove the return line from the ATF radiator and start the car (low idle) and the torque converter will drain itself (to some extent), then drain and remove the pan, replace the filter and clean the magnets in the pan. Reattach the pan and refill with oil, the trick is to make sure you fill it properly because you need to go through a process of filling the pan, starting the car, move through the gears, topup the pan, repeat the process until it doesn't take any more oil. If you aren't equipped to do it at home, then its really not too hard for a decent shop to do, even without the specialised pumping equipment.