Hey, guys, while others tried other stuff, here's a post I made in another forum. I am not an e90 owner, don't tell anyone!
Hi, everyone. Paying it forward!
I get so much info here, I wanted to go over my troubles with my beloved 525i with 140,000 miles on it. It rides as nice and any new car I have test driven, bu t who wants a new car payment?
The issue was, while coming to a normal stop, regular p, fooon brake pedal, the car would jerk hard when downshifiting, I am guessing gears 3-2 and 2-1. It was driving me nuts. It felt as if someone might be hitting me from the back end and it was very noticeable. t also drove me crazy that mechanics would say, "I think that's normal." ARGH. I might also note when backing out of my garage, slight downhill, I had to press the brakes much harder than I thought I should, not sure if that's related.
I took my car to an Auth'd BMW dealership in the State of NY (for now I will not say the dealership's name, as they've been very understanding. More on that later.) They said, no problem, we can fix that by dropping the pan, ensuring fluid levels are right and by definition, putting in a new filter (part of the pan?) and Transmission reset. I was specific when I asked (for this 2004 with 140,000 miles) "will this correct the problem?" Thinking, maybe I have to trade it in. Cheerfully the client specialist said, "Yes, this will work." Sadly, same issue the instant I got the car back. I took the head mechanic for a ride and he did acknowledge the problem. The services manager said he'd try to find me a deal on a third party that could rebuild my transmission. He suggested he'd offset further costs by $1400. We'll see. That's where forums like this are so valuable. I did a bunch of research on this issue and found quite a bit. This doesn't work, that doesn't work, this doesn't work -- but I found lengthy posts about solenoids and sleeves that looked promising.
Fast forward. After reading tons and tons of info on my specific transmission (I think it's a ZF GA6HP19z.) I decided to buy a solenoid kit and mechatronics adapter from CTSC from Klaus, who was awesome. (I have no relationship to Klaus or this company except one-time happy customer,.)
https://www.thectsc.com/products/sol...ft-36-115.html
and
https://www.thectsc.com/products/mec...p21-44-45.html.,
I asked around town and found a great (albeit extremely busy!) transmission shop called Buchholtz Transmission. Mark the owner is the nicest, most honest guy ever, and great/knowledgeable guys in the shop,. Any way, I told him we were in this together, I wanted to have him install these two PNs, I'll take the chance, but needed to wait quite a while for him to fit me in. (Understandable -- these guys have unlimited work!)
He finished my car this afternoon. Wow. No jerk,!!!! Smooth as silk! Downshifts are unnoticeable coming to a stop (the way they should be!). I hugged my wife when I got home, told her I now don't want to buy a new car (that she gave me the thumbs up to do!) Now, it could be new fluids, the reset, the solenoids or the mechatronics sleeve -- but this combination seemed to do the trick. And yes, could there be a further issue? Sure! But at least we know the transmission/hardware is fine! I hope this helps someone else out there. I found this info on an e39 post in another forum. (Mark, you are a great guy and the world is better because of you.)
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So: Before you spend $5000 on a new transmission or a rebuild, this may work for you, too. I am looking for a credit or compensation from the Auth'd BMW shop for my $1400. They've been very good to me and I am confident they will do the right thing and possibly credit me.
I hope it helps others.
"The best car on the road? One that's paid for." - free advice