I've been looking and have found no real info on a recommended mileage preventive maintenance type rebuilt for the M90. I've got 95K on my car and will be replacing the LIM and I figured that since I have the upper end off, I might do some invasive PM'* on the SC as well. I'll definitely replace the coupler, but not sure about the bearings, etc. Any wisdom will be appreciated.

As long as you don't hear the bearings they should be fine. But if you pull the rotors you will need to add some grease to the neadle bearings. If the coupler is solid there'* no reason to change it. Just change the snout oil.

Kind of what I was figured, but I needed a gut check. While I have the SC off the engine, I'm going to add a drain to the snout to facilitate oil changing in the future and I figured at a minimum I might as well change the coupler at the same time. I'll do a write up on drain set up so we have it for future use.

I have a write up on changing teh oil. I just suck it out. There'* very little room to add a drain. The oil area is rather small. But would like to see what you come up with. Can't wait to here your comments about the smell.

I changed the oil not too long ago and used a small hand held vacuum pump. I believe I even commented in another thread about the smell. It'* definitely an odor that I have never encountered before and was totally surprised to smell something like that off of any automotive fluid. I'm a few weeks away from doing the work. Headers first!

I also looked into a drain before. With the SC belt, LIM and coolant elbow locations it doesn't seem overly easy. It'll be nice to hear a fresh perspective, although at this point...draining it every 30K and refilling with fresh isn't enough work in my case to warrant me pushing ahead.

Go for it PH.