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Old 05-19-2015, 10:53 PM
desertfire desertfire is offline
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Red face 2005 4.8is transmission shifting / slipping issue

Firstly, I’d like to say that this forum is an awesome treasure trove of information for anyone who owns an X5 and is a definite asset that all X5 owners should leverage. A lot of good and interesting information.
Recently I “adopted” a 2005 X5 (E53) 4.8is in Imola Red with all the trimmings and options… nothing was spared. It is an absolutely fantastic vehicle and has been kept in pristine condition.

Some info on the vehicle:

· 182k miles
o Nearly all open highway miles
o Previous owner used it as business transport between Michigan and Utah
o Was used for local commuting for < 25k miles through its lifetime
o Previous owner is a mechanical aficionado and installed a run-time clock… engine has 2694 hours on it
· Engine runs like a clock
o Has an amazing (intoxicating) sound when it “wakes up”
o No squealing
o No knocking
o Averages about 24MPG
o No leaks (water or oil)
o Occasionally leaves a puff of smoke when sitting idle for a while
o Doesn’t burn very much oil at all (hasn’t burnt anything noticeable in about 2500 miles)
o Oil was replaced at 9k intervals by original owner
· No electrical issues to report
o Original battery was replaced last week…. (10 years and still going…. ) It didn’t need to be replaced but I did anyway.

Now, on to the issue I am experiencing….
When accelerating it appears that when shifting from 4th to 5th gear the 5th gear catches and then appears to slip out of gear and then the transmission makes a “whizzing” sound, much like a slipping belt and a little like the sound an air ratchet makes when unscrewing a wheel lug (not the hammer part when loosening it). If I let go of the accelerator the gear proceeds to change and things carry on. If I don’t let go of the accelerator the transmission goes into “transmission failsafe program” mode and is basically locked into 3rd gear. If I come to a stop and shut the car off and restart the vehicle the error goes away and things carry on like it hasn’t happened. I have noticed that it happens more when doing a left turn and also when on an upgrade.

Additional details:

· ZF 6HP26 transmission
· Transmission never replaced
· It appears to occur when approaching ~3.5k RPM although has occurred with far less.
· “Garage”shifting from P to R/N/D and back and forth has no issues and does not make any clunking noises. It does take a few seconds for the gear to settle in, but it is not taking an overly long time… (just not crisp) and does not “lurch”.
· In Standard drive mode the problem occurs when shifting from 4th to 5th gear, as far as I can count it.
· In Sport mode the issue doesn’t happen as pronounced and occurs less, but nonetheless occurs.
o One time in Sport mode I didn’t release the gas in time and it went to failsafe mode. It stored a code P17E9 which I have yet to figure out what it relates to. Looked online but haven’t found anything. The code was cleared to see if it was a consistent issue and it has not happened again, although the slipping occurs.
· Another note on the Sport mode is that occasionally a gear will be held for an excessively long time, even if backing off the accelerator, and the only way to release it is to flip back to Standard mode.
· In “Manual” mode the gears shift fine and do not necessarily “slip”. The shifting works well, although it is not paddle-shift quick, but is consistent. There is a little hesitation settling into 4th and 5th but it does not skip out of gear at all.
· No smells or burning of transmission fluid is apparent.

I replaced the transmission fluid to see if the symptoms would alleviate and the transmission appears to run smoother, although the gear shift issue is still occurring. The shift from 1st to 2nd used to hesitate and kick hard when cold but since the fluid change it has been much smoother.
After reading some of the posts on the forum I replaced the battery (the original one apparently was only retaining a 34% charge) and the issue persisted. The alternator checks out fine as well putting out a consistent ~14.2 volts.

I do realize at this point that some work will be needed on the transmission and am not trying to avoid it but am rather interested in understanding what the appropriate fix is for the problem since the issue appears under specific circumstances. Replacing the transmission and torque converter, as much as it is a surefire solution, feels much like shooting a fly with a cannon. I am reserving my judgment on the symptoms as I am no expert in the area of automatic transmissions. I prefer to understand the issue as well as the potential remediation options before jumping into the lion’s den of mechanics that will obviously bleed the issue to the fullest extent they can.

My other vehicle is a 2005 330i ZHP with very low miles and is a joy to drive. It is refreshing to feel that the experience in this variant of the E53 is very sporty. Also, the vehicle has a certain poise and stance that sets it apart from others which inspires me to want to resolve the issue with this vehicle and give it a good rest of its life ahead.
According to a number of other posts there are various areas to look into, such as the MAF sensor, ABS control, Throttle Position Sensor, etc… , but before blindly throwing effort at trying to resolve the problem I am turning to you for support and advice on where to “dig”.

I am very mechanically inclined and will understand any level of technical explanation you may share. Also, if there is any solution that does not involve removing the transmission I will handle it myself as I am fully equipped from a tooling perspective. I don’t have a lift or I would handle the transmission removal as well if required.

Thanks in advance for your help and support!

Last edited by desertfire; 05-19-2015 at 11:38 PM. Reason: formatting
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