good results from rlltide12 using friction modifier in the transfer case
>see rlltide12 write up on his transfer case saga and the success with friction modifier
>post one etc below
http://www.bimmerfest.com/forums/showthread.php?p=11791185#post11791185
rlltide12 rlltide12 is online now
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Location: Alabama
Join Date: Dec 2017
Posts: 5
Mein Auto: 2007 X3 3.0si M-Sport
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07 E83 M-Sport Surging Under Acceleration
I recently had an experience with my 07 X3 that I thought I would share in hopes it might help someone.
I bought the vehicle about a year ago, 90K miles on the clock, 3.0 N52/GA6L45R/ATC400, and ever since that time, I have experienced a surge/jerk/miss/wheel slip feeling when under acceleration. The engine seemed to be running perfect.The only code the vehicle was throwing was a VANOS solenoid sticking error.
I began by changing both the VANOS solenoids. No change.
After reading some here, I used DIS57 to clear adaptations per Yomama and swampx3s forum fully expecting that to resolve the issue. No joy.
Next, the engine still had 6 Bosch coil packs. I talked to the dealership, and a TSB exists stating the Bosch coil packs were prone to failure due to heat. Suggested replacing with Delco. Purchased 6 new coil packs and plugs. Installed, and of course, no change.
I had also read of many with upstream o2 sensors causing this type of issue. Unplugged both of mine to put it in limp mode, still surging.
I began thinking that something transmission/torque converter could possibly be causing the issue. It felt like a slipping tire or clutch almost. So on that premise, I changed transmission fluid and filter, and added a shudder stop addative. Again, no change.
Checked all driveshafts/guibo. All good and tight.
Then my thoughts shifted to the transfer case. I knew that some have an issue with the gears in the actuator stripping, but under most all circumstances, the trio of lights would be on. I had no lights, but knowing this is a common issue, I figured what the heck, I'll change them as preventative maintenance.
To test, I pulled the plug off the actuator and test drove. Bingo! The surge was gone! Ordered the gears and a litre of TF-0870 oil. Put the car up on the lift, removed the actuator, disassembled it, and the black gear had about 6 teeth with damage. Replaced the gears, added new oil, reassembled, used ISTA to perform oil change test plan and cleared VGT adaptations, and took it for a test drive.
The surge was almost gone, but it was still there. S*&@! Talked to another member here (thanks swampx3) and decided to try some LSD Friction Modifier, typically used in limited slip rear ends, in the tcase. My thought was that LSDs use clutch packs bathed in gear oil, and this addative helps the clutches do their job. I drained off some fluid and put 3oz in. Took it for another test drive and it is smooth as glass!
It took me almost a year to track this issue down, mostly because 2 hours separated me from my car lift and it was tough to get up and work on it. I had not found this solution here yet, but others may have used this solution in the past. This solution is not on any repair plans from BMW, so try it at your on risk. I don't know how long it will solve my issue, but for now it is prolonging what I figure is a worn clutch pack in my tcase. Feel free to chime in and add your experience!