Its been 30,196km since i last change my ATF on my e30, 4HP22. i was told by the previous owner that he rebuild the slushbox. so i presume it was like 3-4 years since it got the filter change. i bought the filter kit (comes with the metal filter,rubber gasket and oring) for i think rm55 for some time oledi from BA. tools needed: T27 tork-> to remove the 3 torkscrew for the mesh filter.+-3L of ATF , i use ACDelco10mm socket to remove 6 brackets that hold the atf pan.30mm spanner to remove the atf refill port. 5mm allenkey or in my case 12mm spanner , yeah i modified the drain plug as i found it easy to round/strip the 5mm nut.a lot of old news paper.lot of ragsprocedure: i would suggest u to 1st detach the -ve battery cable. now u could start with removing the atf from the pan by removing the 12mm drain plug. make sure u put lots of old news paper on ur driveway as this job will mess the floor no matter how much carefull ull be ;-p.nx remove the atf refill port(30mm spanner) and remove it completely. make sure u remember wer the refill port past thru or u will hv to play guessing game when reinstall. i didnt detach the -ve battery cable when i do this and guess what, i saw spark when the refill port touched the expose starter cable. once the left over atf drops slowly, u coud now start to remove the pan. there are 6 bracket that hold 4HP22 atf oil pan. it is wise that u could clean the surrouding from all the sand n muddy goof before u remove the oilpan out. i removed the first 4 and left the last to finger tight. hold the bottom of the pan with one hand while the other hand removing the last 2 brackets. once free, make sure ur oil collector handy to collect the rest of the fluid. put the oilpan aside. now u could see the exposed steel filter. remove the 3 torkscrew with ur T27. slowly remove the filter away as there will be more atf drops.errr btw someone told me that the old atf collected shudnt look soapy and bubble. mine was clear. bubble indicate bad slushbox internals.inside the oilpan, theres 2 magnets to pick up tiny metal residue. becos the residue is so tiny it looks like goof/mud. i cleaned the internal & external throughly and seat back the 2 magnet in place. i assemble the new filter+o-ring and also assemble the rubber gasket to the oilpan. reinstallation is basically reverse of removal ;-) make sure u tight the nuts as per spec/not overtighten. refill +-3L of fresh atf thru the dip stick hole. check the fluid level when the engine running & refill if necessary. the shifting felf alot betta this morning (from cold) especially from 1st to 2nd gear. the whole job took me bout 2 hrs. i plan the nx filter change after 2 atf change(60,000km). btw i dont like the power flush method that used by some shop. i would suggest u to do 3-4 atf change in 2-3 weeks as this method is more gentle to the internals as compare to the power flush method. anyway its ur slushbox n i let u decide on ur own ;-Pgood luck 
