transmission - a mind of its own!!
 

Folks, what searching I did of the archives did not reveal a problem like this. If it's been previously covered, I apologize - but it was not there to easily find.

Here's the issue. My '02 X5 4.4 transmission has a mind of its own.
You can be cruising at 55 MPH, and it decides it wants to be in 4th, or even 3rd! That's one example of this odd behavior.

In city driving, say at 45 MPH, I can let off the accelerator to slow down for a traffic signal. The transmission will downshift, slowing the vehicle down through each gear, to 2nd gear.

These "actions" are quite random. I've no clue. A possessed unit?? LOL!

SO... any ideas? What's the scoop?

Oh. I did try the "transmission reset" - to no avail.

Thanks!

Kim

I have a similar issue with my 04, 4.8 X5. In my case, it seems to happen when I come to a somewhat quick stop, say at a light or stop sign. When go to take off, the car revs fast and almost to the 4 on the RPMs. I've taken it in several times and they swear it's fine. The dealer told me these cars have "tricky transmissions". One guy told me that I just need to give the car more time to downshift as I come to a stop. I'm not slamming the breaks or anything, so I don't see why the car can't downshift at different speeds.

Are you guys in Sport Mode when this occurs?

This is a common problem with the X5, I own an 01 X5 and I recently just hit 117,609K.

The down shifting became such an annoying problem to the point that I try not to stop the car as much while i drive, i tap on the brakes every now and then just so i don't feel it as much.

Im very grateful I have 3rd party warranty on my X. I will be rebuilding my transmission i figure around January, dont ask me why I am waiting.... Its for a few reasons...

I noticed alot of X5s past 100K have a hard down shift from the transmission, I also have had a few friends who rebuilt there transmissions and it was gone and everything is fine with there trannys now. I know someone with over 218K now and hes running strong after a rebuilt transmission. He of course had to maintain it properly by changing Spark plugs on time, replacing brakes and rotors on time, do your oil changes on time, not KILL the car by driving constantly on 7 RPMS....

From my personal experience, as long as the engine has been taken care of, they can last a life time....

I only have 52K miles on mine and I have CPO warranty until 7/10 but can't get a dealer to acknowledge a problem with my trans. I'm not in sport mode when this happens. I love the car but this issue can get a little annoying, especially when it jerks you into the next gear after take off. I live in Chicago so it's hard to avoid quick stops sometimes!

I also have a 2002 that tends to shift at random around 50-60 mph,, it will go down to 4 or 3 like it is trying to kick down to passing gear but only during very light acceleration. I also have the down shift problem. It really doesn't appear to be in the transmission, because it doesn't slip or not shift correctly. I had the exact same problem on a Jeep and it was the Throttle position sensor making the computer think the throttle was at a different location and shifting the trans according. The X5 doesn't have this sensor but rather an ECU which is very expensive. It appears to be electornic and not mechanical, hence the reason many people rebuild the trans and it still does the same thing. Maybe a good BMW trans man could shed some light...

possible cure?
 

Since beginning this thread, here's what I've done.
To answer a question, No - not in the sport mode at all. Just in normal Drive. Random shifts as some of you have observed. Now for what I've done.

My independent garage said my transmission showed a temperature sensor fault. I replaced the following items: the wiring harness with temperature sensor (that's the description); the 3 servos; and, the rear pulse generator. When I removed the pulse generator, the oil around it was very dirty - worse than the regular oil. Beware of the torx bolts. I had 2 to strip on me during all of this. I also pulled the front pulse generator and noticed the same bad oil. I cleaned that pulse generator.

Put everything together and added fresh fluid (I changed the previous fluid at 70k miles).

The result? ALL is well!!!!! In the combination of what I changed, it fixed it. I thought about the link over to the throttle position, but this "fix" shot down that notion.

Well I am hoping that when i rebuild my tranny there going to do all that for me.

Transmission
 

Hey thanks HSV2006,, you may have found a common failure in that "wiring harness temperature sensor". It seems mine is sometimes a little temperature related. Where did you find the harness and sensor, how much? As for the servo's and pulse generator. They don't really fit my diagnostics, but I will clean them and test them. Is the harness inside the transmission pan? Any help would be great....

I had a similar problem and the stealer ended up replacing a wiring harness that was inside the tranny oil pan. Apparently the housing for the harness had failed so oil was getting into the wires. I couldn't reproduce it so had trouble getting it fixed. Eventually it finally got to the point that it was permanently screwed up so they were able to find it. Bizarre but has been solid ever sense so like 5 months.

The harness and sensor is #24341423719 - I found it for less than $245. It is mostly in the transmission pan. Remove the oil - remove the pan. The harness has an external connector - remove it next. Next disconnect all the connectors. NOTE: At the front and rear of the transmission are 2 connectors the require removal of bolts holding the clips. You must remove the bolts else you will break the clips (I broke a clip). These are the pulse generators. Remove them and clean them. Last step - remove the retaining ring which holds the connector/harness in place. This is on the outside of the transmission. It is the last step before removing the harness. When you install the new harness - the retaining ring is the first thing to install once the harness is in place.
For a parts break out see realoem.com.

I had the same issue pressed BMW and got the tranny replaced! Must be able to replicate it with a tech! This took some patience and luck!

I promise you, they know about it...they're just waiting for the clock to burn up so they don't have to pay for it. CPO repairs don't pay as much as normal dealership rates, otherwise they'd replace it w/o a problem knowing they're going to make their money regardless. Hound them now or potentially pay $5-6k later...it sucks, but you gotta do what you gotta do.

Hopefully BMW trained techs like killcrap or Weasel can comment on these temp sensors, the wiring harnesses, along w/ these servos and generators...this would be a substantial saving to replace a few bolts ons versus the whole transmission.

excellent thread here
carry on .

+1
I have similar probs albeit not that often and I've noted that it only happens (mostly) when I'm driving down a hill and touch the brakes whilst doing around 60 - 70kmph. Note: I only have a 3.0i, not a V8 as I thought this was only a V8 problem, not so. We have a lot of sneeky radar cop cars on the GC that park within other local cars and catch you as you come down these steep roads.

Ol' Bluey throws it down a gear the moment I just touch/tap the brakes as if to prepare to either slow down, overtake or come to a stop, weird.

I've come to understand the car and try not to run up and down said hilly road over the speed limit (usually 60kmph).

Strange how it doesn't happen if i'm running down these hilly roads at speed or under 50kmph.

As amacman said, carry on. Very interesting read.....:thumbup:

Hey HSV2006,,, I found the harness for $150, but have not ordered it yet. It doesn't do it that often, but my problem is the same as yours and the temperature harness will probably fix it. Thanks for your help and will probably replace it and do the other cleaning and maintenance while I am in there.... your help is greatly appreciated.... thanks Clyde

This thread just saved me thousands of dollars =) Im out of warranty 03 X5 4.4 108k miles. I've had the exact problem HSV2006 described for about 2 or 3 months. I didnt want to take it in because I didnt want to consider paying $5k or $6k for a new tranny.

Anyway after reading the thread I printed it and took it to the shop. I was 90% sure it was my problem but I caught h*ll getting someone to do the job with out giving me all the "rickamorero". 1 shop wouldnt touch it, even after telling another shop this is the exact repair I wanted and wouldnt fault them if it wasnt fixed, they still wouldnt do it( I couldnt get them to hook it up to the computer with out doing "pin testing" and other cr*p I didnt think I needed). Apparently auto shops dont like customers to come in and tell them what they want done?

Any way I finally convinced my local dealer Moritz BMW to hook it up to the computer. Sure enough it was the temp sensor on the wire harness. Paid $215 for the harness it'll be here Monday and I should be good to go. Total repairs will come out to be about $700 =) The only difference in mine is that the seals werent broken so oil wasnt in the compartment, the harness was just shorting out. Long stort short if you're having similar issues check the wiring harness.

Thanks a bunch HSV2006 =)

So do we know what years this problem is related too?

^^^^^^
as lay3r3 said
notice garage mechanics opened wiring harness linking gearbox to gearshift to clean inside.... some yucky creamy paste creating electrical connections where shudnt b

Gents

I'm not sure if this is the same issue but my 2002 4.6is lunges forward just as I am about to stop to a standstill ..... any comments appreciated?

I have these issues logged under a warranty and am about to book in the car for service and warranty fixes

Schanck

The notorious rough downshift...do a search on here, plenty of discussion about this. All the dealer will do is top off the trany oil or maybe a trany reset. There doesn't seem to be any type of awareness on their part so there's no service bulletin for the issue. The only E53 trany service bulletin i've come across is for 2004-2006 V8.

you've inspired me. i think while i'm in there i may as well replace the pulse generators. i did get a speed sensor error, but i only use a generic OBD II scanner. there is also a crankshaft pulse generator external on the bell housing. i think i'm going to check that as well. (just make sure the connections are clean.)

i wish i had a lift.

transmission wiring harness
 

I want everyone to know that my initial repair was a temporary fix and did not fix the problem. What I thought was temperature sensors, were actually pulse generators (impedance coils). I guess while I was checking the wiring, I did enough movement of the wires to make the temperature sensor that is built into the wiring harness to makeup and work correctly for a while. The weird shifting pattern of high rpms followed by hard down shifting was cause by the transmission wiring harness internal temperature sensor. This sensor is a small looking resistor about 1/8 inch long and 1/16 inch in diameter that is crimped between two wires. When heated with a heat gun, the resistance increased. I bought the harness for $190 and had a local trans shop install it for $150. My X5 no longer has a transmission with its own mind. Hope this helps others...

Pics, part number, etc?

Hello. I have the 4,8is 2004, with transmission problems."a mind of it,s own". Does any body know if it,s possible to get the wire hardness for the transmission, as to the 4,6is.? Cant find it in real.com or so. (Sorry bad english, i,m from Norway)

After reading this it may have saved me from shooting my X5. Here is my issue as best as I can describe it.

Driving down the Interstate today at 70 mph. The tranny just shifted into 4th for no reason. No accel or decel, just driving along. It wouldn't shift back into 5th. After exiting Interstate, it had hard shifts down to 3rd, 2nd and 1st. At accel from light, 1st to 2nd was fairly smooth but getting to 3rd took to over 4k RPM - same for 4th. I think normal shift point is around 2500.

Took it to indy shop where they found a code that showed tranny temp at 136 C but actual temp as tested was 89 C. They weren't sure what the issue was so I drove home. Same tranny issues as above on the drive home.

If I replace the tranny temp sensor, will this theoretically fix the problem? Have never had any trouble with the tranny prior and have no reason to believe it's going to go kablamo.

Not absolutely for sure, but it is a logical first step. It could also be a wiring problem.

Got the X5 back today.

Local shop changed the tranny fluid including a flush, Pan Gasket, Filter and Tranny Wiring Harness. Problem solved. I love this forum.

After speaking with the local shop we agreed that they were going to change the wiring harness even though they've never personally seen this issue. I printed a few of the threads on this forum relating to hard downshift and relevant tranny issues and voila!!!!! a fixed transmission.

Thanks for solving my problem and saving me thousands of dollars.

As much as I interact on these forums, I still don't know what harness people are talking about.

reply
 

In the X5 4.4 transmission is a part called "wiring harness with temperature sensor". Part 24341423719?

Thanks for the part # - RealOEM.com * Part Cross-reference