Quote:
Originally Posted by Stin999
Hi everyone,
Recently I've been trying to diagnose an on going issue I've been having with my 2015 335i Xdrive. Any help would be much appreciated.
If i'm driving the car in manual mode (my car is an automatic), let's say cruising in 3rd gear, and I lift off the gas, I get an uncomfortable lurch forward sensation. The lower the RPM and gear, the worse the sensation. If I was in 1st gear and I let off the gas briefly, the car would very aggressively rock back and forth for a second before settling.
If I'm downshifting from 3rd gear to 2nd gear, I get an uncomfortable rock back and forth motion as well. Happens more so when downshifting at a lower RPMs. It kind of lurches forward and then rocks back and forth again for a brief second before settling and continuing on.
This also happens in automatic. If i'm coming a stop, it almost feels like the car doesn't want to downshift gears, and holds on to them until the very last second and then lurches me forward while quickly downshifting before coming to a complete stop.
My car has 48k miles. It's tuned BM3 Stage 1 (93 Octane). Supporting mods are MPPK intake, Fabspeed highflow catted downpipe, ER chargepipe, AWE performance mid-pipe and AWE cat-back exhaust.
Spark plugs changed within the last 4000 miles.
Transmission fluid changed in the last 1500 miles (Issue was going on before this but has progressively started to get worse).
Front and rear diff fluid changed in the last 1500 miles.
Car is running APEX EC-7's with a square setup 245/40/18 tires which were put on 1500 miles ago.
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Could possible be T-Case if i'm right the tires size from BMW/ For that car is 225/45R18 I know here we cant put anything not BMW (Approved tires sizes) it can mess with the t-case even if the tires work with a tire cal (from 1010tire. if you have warranty i would get it checked out but i'd put the approved tire size back on before getting it checked.