i have a 1995 525i with an automatic transmission. the car had a rebuilt transmission installed at 117,000 miles and has 172,000 miles on it now. my wife mentioned the transmission was not shifting smoothly and i changed the fluid and filter. the transmission works fine now except right after it shifts into third gear there is a rumble and vibration, then it smooths out and shifts fine into fourth. the transmission shifts at 2000 rpms under normal driving. if i shift the car manually at 3000 rpms i don't notice the problem. are there more servicable parts on this transmission? should this car shift at such low rpms? am i heading toward another transmission?
What kind of ATF did you use? Are you certain that you have put enough fluid in? Just covering the basics.
i used dextron lll and added the fluid until it came out the filler hole, the car was elevated and running with the transmission in neutral. i did a test drive and rechecked the fluid, at this time some fluid came out. i've heard of valve boby rebuilds but the bentley manual does not describe this procedure. can a transmission shop do a more effective flush?
Well, that's the way to do it. You may wish to check it again, just to be safe. It should be running and warm, but not test-drive hot. A trans shop can do a more thorough flush, but there is no way of telling how much it will help, if at all.
It's an autotragic and has a mind of its own. Automatics usually shift when they realized that there isn't enough power being requested through the throttle. So, if you floor it until about 4000 rpm and let go, it will shift around there, because there is no need to keep the revs up. So, it shifting at 2k rpm is all because of your driving style. If you want it to shift above 3k rpm, then you'll just have to have a heavier foot than usual. A good way to get the autotragic to shift when you want is to press the throttle enough to get it to the rpm you want to shift at and let go of the throttle (if not completely then decrease the amount of throttle by about half) and that is certain to get it to upshift. To downshift, floor it for about half a second and it will downshift for you. Yes, I got plenty of practice in the autotragic of the 4cylinder fury of the first auto car I drove. *shudder*
First I'd check the guibo/Flex disk and make sure it's not ripped to pieces or lose. That gave me bumps in the night at low gear although that more than likely isn't the issue. Second, you could try putting in a EAT(D'Sylva), Jim Conforti(Turner Motorsport), or Dinan ECU chip. http://www.dsylva-tech.ca/ http://www.turnermotorsport.com/ http://www.dinancars.com/ They run about 200 bucks. Dinan also make a transmission chip that changes the rev shifting to higher RPM's. I use this with the turner motorsports/Conforti ECU. http://www.dinancars.com/store/product.php?productid=1518&cat=692&page=1 It works well for me. No speed limit, rev's up to 7K usually, and shifts at 3K-3.5K RPM for faster acceleration. That may be a good choice for you if you are sure it's not mechanical. The transmission chip also runs $200. Third, you could remove the battery for a few minutes and let the ECU reset and then drive the way you wish. Keep in mind that if you have an OE radio in there, you'll need the unlock code. If you have a modern radio, no issues. This is assuming your transmission doesn't need to be rebuilt. If it does need to be repaired, you can ship it off to http://www.metricmechanic.com/catalog/ultimate-transmission-part-1.php. They've been working on BMW's for awhile now and do decent work.
