Changing trranny fluid???

[vivanov1]

Hey, ive seen threads on changing the tranny fluid, and am wondering if its necessary or not... it seems like a pretty simple and easy job, and relatively cheap. should i do it as preventative maintenance at 54k miles or dont even bother?? thansks?

PS. Do X5's have a timing belt or chain? i didnt see anyone on here doing the timing belts? pleae let me know. thanks.

[Wayne's World]

Viva - if you think you'll feel better if you got fresh fluid in there, do it. Trannies have been known to last well past the 100K mark without a fluid change, albeit performance isn't as 'new.' The way I look at it - it's oil, like anything else and it will break down over time and with heat/friction. I would recommend changing the transmission oil every 30K. For some more detail on the change procedure, see my write up here: http://www.xoutpost.com/bmw-sav-foru...tion-3-0i.html

[X5Sport]

I believe the camshafts/timing gears are all chain driven - no belts to snap - on all BMW engines whether Petrol or Diesel.

Having once been in a company owned Ford minivan which had a fibre reinforced belt that snapped at less than 4,000 miles and lunched the engine, I try to avoid anything with belt drive. I just don't trust them. Where I have had belts on cars I always change them at around 30,000 miles, or half their stated life if shorter.

Twenty-five years ago I was working on a Police Fleet where we were changing belts every 3,000 miles on one particular engine design as they were failing in use so frequently. I can't remember how many belts snapped in that first year but it was a lot. All covered under warranty, but it must have cost the manufacturer dearly. Strangely we switched fleet vehicle manufacturer shortly thereafter........I wonder why