transmission - a mind of its own!!

[Schanck]

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

[chilliwilli]

Originally Posted by Schanck

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.

[tonycajjo]

Originally Posted by HSV2006

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.

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.

[cmartin248]

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...

[m5james]

Pics, part number, etc?

[wilhelm2909]

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)

[hawkeye12345]

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.

[JCL]

Originally Posted by hawkeye12345

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.

[hawkeye12345]

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.

[m5james]

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