Transmission Problem - 2006 325cic

Hello all,

So recently I've been experiencing some issues with my automatic transmission (I think its a GM tranny). I have a 2006 325ci convertible with 52,000 miles. When I first bought the car I realized soon after that in certain situations it does not shift when it is supposed to. I took the car to a reputable shop to get a transmission flush.

Recently its been over-reving mainly when shifting from 3rd to 4th, and most of the time when it is on some sort of grade, up or down. The car will shift fine from 1-2-3 but when it shifts from 3-4 sometimes the revs get to 3-4k rpm under normal acceleration and it is obvious the car should be upshifting.

I've tried searching to see if I could find any info on this and some people mentioned a firmware update for the TCM/TCU. Other than going to the dealer is there any way to figure out if this would be needed?

I appreciate your help.... right I'm pretty bummed being I just bought the car. If I'm going to be running into major tranny problems in the future I might just sell the car.

I should also note that these problems are occurring when in D, I will drive around in S and see if it makes a difference.

Bump

Was about to tell you to go to an e90 forum before I realized the 'verts carried over into '06.

Hate to say it, but that sounds indicative of a sticking shift solenoid. The fact that you bought an automatic e46 means there's a solid chance you'll be running into major tranny problems in the future, lol.

I'll give you the same advice I gave somebody else. It won't fix a messed up trans, but just try it. (1) Disconnect the negative battery terminal for 10-15 mins Just try this first, and then reconnect, (2) after reconnecting the battery, get in the car and turn the key to the position just prior to start up. Floor the gas pedal and count to 40 in your head (it's 30 seconds, but just to make sure you did it right). Then let off the pedal and turn the car on. Go for a drive and see if the trans is back to normal. There is controversy surrounding whether there is any validity to these procedures, but my trans gets driven hard and I always do this after driving it hard, because after hard drives the trans likes to keep trying to shift higher in the rpm band for a couple days. This procedure usually skips those days and brings it back to normal for me. When I do it... In "D" mode, I can no longer feel shifts from 1st to 2nd to 3rd, I can barely feel to 4th and 5th you can feel like a normal auto trans. I do it often though because I also drive my car hard often.

Originally Posted by lcoleman

Was about to tell you to go to an e90 forum before I realized the 'verts carried over into '06.

Hate to say it, but that sounds indicative of a sticking shift solenoid. The fact that you bought an automatic e46 means there's a solid chance you'll be running into major tranny problems in the future, lol.

Yea, I've confused a few people with the 2006 vert already.... should have bought a manual, I forgot how much I despise automatics, especially ones that don't upshift. I am not well versed in auto-transmission talk, it this shift-soleniod something that can be replaced, or is it deep in bowels of this POS hunk of metal GM/BMW calls a transmission?

Teddy7- Thanks for the tip. I attempted to reset the TCM this way before, but never after disconnecting the battery. I will try again.

On another note, is there any way that this could be caused by a vacuum leak somewhere? I need to replace my upper intake boot and I just haven't had the time yet.

Vacuum leak doesn't sound possible. Unlike the old Mercedes which had vacuum-acuated shifting, I'm pretty sure the e46 is 100% computer controlled.

As far as I know, none of the replacement parts are available separately...generally the rebuilt units use inferior parts from the Orient, so I'd steer clear. Do you know how the fluid looked when it was flushed? That will give you a lot of insight as to how deep the problems go.

The tech told me that the fluid was pretty dirty, not quite sure if that meant metal filings or just dark color.

Let me also add that the car drives pretty normal on flat roads and when I floor it. Its more when i'm just trying to drive normally, like pedal 1/4 way depressed. Also when the tranny finally decides to shift from 3-4, it is very smooth, not jerky. Also, the tranny shifts fine in all gears when in STEP mode.

Not sure if I would want to put another auto in this car if the tranny needs replacing..... I think I would get a quote on a manual swap. I think I could do most of the work myself... except for the reflash.

I hope the tech knows that the bmw factory fluid is naturally a forest green color. It is not the normal pinkish red color like the common trans fluids. So if the tech wasn't aware of this, then his statement of it being dirty may be referring to this. +1 on the manual swap. I'll be doing the same when my auto eventually goes out. If I were you, I wouldn't be too worried. If it is shifting smooth and it is simply revving a little higher before shifting then it may just be adaptations. Now if it is revving higher and seems to not be moving or increasing speed....then I'd be worried.

You might as well just change the fluid with Dexron VI anyway. It's probably due and it couldn't hurt. The fact that it's smooth everywhere else though tells me it may just be a solenoid or something though. If you do the fluid flush, drain and fill with Dexron VI, then drain, replace filter/gasket, refill. That gets you something like 85-90% new fluid.

Coupes (not necessarily just convertibles) carried over for 2006. coupe/convertible/m3.

anyway change fluid and filter w/ proper parts and if that doesn't change it, i hate to say it but it sounds like either the valve body, seals, clutch packs, etc are worn. premature but it happens. not sure what else could cause that. MAF could affect shifting as well. what kind of filter do you have on the car? what mods?

As for the flush, I am pretty confident that the shop I used completed the service to the highest spec. They are a very well respected indy.

The car is fully stock. Based on the above, you would recommend re-flushing the transmission?

I am going to pick up an upper intake boot tonight and switch that out, is it possible that the vacuum leak would cause the MAF to send improper signals to the TCM? I was throwing codes until I replaced my lower boot, (I didn't realize the upper was also on its way out) but now I am code free.

Originally Posted by mxracer707

As for the flush, I am pretty confident that the shop I used completed the service to the highest spec. They are a very well respected indy.

The car is fully stock. Based on the above, you would recommend re-flushing the transmission?

I am going to pick up an upper intake boot tonight and switch that out, is it possible that the vacuum leak would cause the MAF to send improper signals to the TCM? I was throwing codes until I replaced my lower boot, (I didn't realize the upper was also on its way out) but now I am code free.

If the slipping started occuring before you changed the fluid, i doubt the fluid was needing changing. should be fine at your mileage and age. i would then suspect a mechanical problem with the transmission.

if it started after the fluid change, then i would suspect the wrong fluid was used

Originally Posted by E46Mango

If the slipping started occuring before you changed the fluid, i doubt the fluid was needing changing. should be fine at your mileage and age. i would then suspect a mechanical problem with the transmission.

if it started after the fluid change, then i would suspect the wrong fluid was used

Tranny was experiencing issues before I changed the fluid.. its very strange... its definitely an intermittent issue, just drove the car to lunch and it was fine. Like I said its not slipping at all, just not shifting normally.

Back to my original post, have you ever heard of a TCM reflash/software update on these cars?

Originally Posted by mxracer707

Tranny was experiencing issues before I changed the fluid.. its very strange... its definitely an intermittent issue, just drove the car to lunch and it was fine. Like I said its not slipping at all, just not shifting normally.

Back to my original post, have you ever heard of a TCM reflash/software update on these cars?

Yes. but that usually doesn't cover up a problem like this. that would mean your car did this from the factory. the update is more of a fine tuning of what already exists (as factory)

maybe see if there's any ghost codes associated with your transmission. (not very familiar with autos)

Originally Posted by E46Mango

Yes. but that usually doesn't cover up a problem like this. that would mean your car did this from the factory. the update is more of a fine tuning of what already exists (as factory)

maybe see if there's any ghost codes associated with your transmission. (not very familiar with autos)

ok thanks for your help. I'll scan it tonight

The update i did on my friend's 2002 330i auto all but eliminated his downshift jerk while coming to a stop light. (it does it like 1 out of 10 times now as opposed to every single time) other than that his trans worked fine before and after the update

Why not replace the shift solenoid?