I've got a 2004 545i which I got when it had 190K on the clock. It now has 402K on the clock & still runs strong. However, now that it's gotten cold out it gets confused between first & second gear & needs to run a while & run thru the gears a few times before it straightens out. The book value of the car is about nothing but it's got new tires, new brakes, new struts, tight suspension, new battery, and a new alternator & still gets 31 mpg on road trips. Because of age, I'm hesitant to dump a bunch of money into a transmission so I've sort of retired the car. (my wife drives it because she likes it better than her newer 550i.) I'm looking for suggestions on how to revive the gearbox since we like having the car around as a spare. Meanwhile, for long trips, I've just gotten a 2013 550xi which is a whole nother animal but I still need some help for the old horse.

 

Wow 405k!!
Here's my logic. If it's worth keeping around it's worth spending a little to keep it running. Anything short of replacing engine and transmission is with it. I'm saying this because I do all my own work including coding modules. I have an 05 that I put around 5k a year and as long as I'm willing to keep it in the driveway I want it to be able to drive across country.

That being said how does it act in manual shifting. When was your last fluid and filter change. Have you had any work done on your valve body before. Are the adaptions reset after fluid and filter change if it has been changed.

 

I had the filter & fluid changed at about 275K. They also worked on the programming since it was banging onto first from a dead stop. It smoothed out nice after that work & has been good until it got cold out. I think i need to get in and drive it to check out manual mode. I didn't think of that. I was just wobbling cause the Eurotech guys who take care of my cars told me a new module could cost $2,000. I think the key to long engine life is 93 octane fuel and oil changes every 4K miles. This one is showing symptoms of valve seal issues but I don''t mind putting oil in if the car is reliable.

 

Ok so the banging in first can only be corrected by VB work. They would have just reset the adaptions because that's what a lot of people did. Most do sleeves and solenoids. I sent mine to get refurbished and got a 10 years warranty for $900 including fluid, filter and seals and what ever else I needed.

You are long overdue for a fluid change. It should at least be changed every 50k. These cars have the same fluid interval as any other car

 

Could be as simple as the five rubber sleeves / seals. Do you do your own work? It is an easy job

 

+1

Yes it could be. When I say VB it means that it has to be dropped. A lot of us did it in our own way and got the same result. If I remember correctly it was the bridge seal that a lot changed also with the sleeves. What I want to stress is the fluid change. BMW does not support a "life interval". Change as you would any car.

 

I can only speak to the 1st gear downshift bang - I fixed mine at first ATF change at 130k. Now it shifts smoother with less of a bang. Still shifts like and old tranny but much more normal.

 

I will throw my two cents in.

A few months back, picked up an ’04 525i with 180K on the clock. Decent shape and well serviced, both dealer and independent shops. Many service records. Trans fluid changes, hoses, spark plugs etc.. Lot of preventive service and it shows.

The 2 -> 1 bump on down-shift appeared pretty quickly. Not a ‘bang', just a hard shift with no noise. Then I was noticing a flair (large jump in revs,) between 4th and 5th when accelerating moderately. Three times when forcing a down-shift while accelerating, the trans would throw an error and go into limp mode.

Because of the overall value of the car, and I am cheap, decided it was time for solenoids, all 5 mechatronic seals, fluid and pan. That is about as much of a gamble as i was willing to take. Replacement trans, not so much. Did the work myself and reset adaptations. Fingers crossed.

Initial drive had a remarkably noticeable change in how it shifted. ‘Generally,’ following the guidelines on relearning adaptations the shift became butter smooth after only a short drive.

Have put over two-thousand miles on since the service, without even a hint of previous issues. Even noticed how well the trans behaves to my driving style now. Almost senses what I want it to do. Spooky.

At first, I thought it was holding gears way to long and was concerned. I was being too critical! Once I relaxed and thought if I was driving manually, I would be holding this gear right now too and not up-shift. And that is exactly what it does. Not being aggressive or abusive in any way. Gentle but spirited driving. ;-)

Cost / Value proposition is to replace the solenoids and all seals at the same time. The fluid is expensive, you don’t want to be dumping it and have to go back in. This is surgery, cut it open once.

What I have gathered from extensive research before attempting this service on my own, only use genuine ZF parts and fluid. Countless sources recommend to never mix different trans fluid brands. The previous (recorded) fluid change was done at a BMW dealer with genuine fluid, 80K + miles and it looked like new when it drained out.

If caught at the earliest signs of trouble, new solenoids and seals seems to be the end-all fix. Continuing to drive when it is malfunctioning is death to your trans.


Valve body removed

Before removing TCU

New solenoids installed and reassembled.