Transmission Question 2004 X5 3.0i

[Mudnyrey]

So I have been reading a lot of threads regarding changing Trans fluid and Filter.
BMW states that it's a lifetime thing, and I've even spoke to a BMW mechanic and other.

BMW sticks with the "Lifetime" fluid and filter without a regular change at 50K or so.
The others say (And I agree) that the fluid like any other breaks down and the filter can only do so much after so long, and changing it every 50k or so.

So here is my concern,
My 2004 has 156k miles on it and it runs and shifts strong. Should I get the Trans Fluid & Filter changed? or should I just leave it be?
I know that if you changed fluids it might do more harm with an older, high milage transmission that has not been serviced as far as I know since it was purchased new.

I'm the 2nd owner of this vehicle and it has always been serviced by BMW.

Thoughts...?

Cheers,

~Mud

[X5Ghost]

Very controversial topic here and you will hear both sides. Im sure you've searched and read quite a bit and if not, please do.

Whatever you decide, do not power flush the tranny.

[JCL]

If you are worried about the filter, then change it. You can always put the old fluid back in.

There is no right answer to changing fluid. Nobody argues that it doesn't break down over time. The debate is whether it has broken down enough to compromise the transmission, compared to the risk of putting in new, high-detergent fluid. Your call.

I wouldn't change it. Again, your call.

[Mudnyrey]

Very controversial, I have done much research on it, or the best I can find. I agree, and most will agree that the trans fluid like any other "Will" break down over time.
Changing the filter wouldn't be such a bad idea and keeping the old fluid and possibly adding just a little new...? The thought of a new filter would allow removal of old sludge and residual wear caused within that I have seen first hand.

I have also heard that if it isn't taken care of from the start compared to one that has, then changing the fluid while parts and fluid have broken down would be ok, however BMW strongly urges not changing the fluid or filter and also commented on potential leaks...?

I can only assume that new fluid would cause a higher pressure within the Transmission, and the springs and valves would be under a lot more stress that normal. Would that be a correct assumption?

Knowing that I have so many miles on the car, it runs outstanding even towing a Harley 1200 mile round trip once in a while. The concern is knowing what could ultimately happen much sooner then I'd like if changing the fluid at this time and stage of miles on this vehicle.

I think i'm better off by not taking any chances of changing the fluid or filter. And just leaving it alone. There's not leaks, shifts strong.

Thanks for the Input!

~Mud

[JCL]

The material that you take out of the pan, which most term 'sludge' is actually sitting on the dirty side of the filter, not hurting anything. If the filter is clogged, then that is a problem. However, the junk usually just sits in the bottom of the pan below the filter.

Parts don't break down with age. There are no higher pressures or stresses on the springs or valves. The fluid does deteriorate with age, as it oxidizes, but the question is whether that is enough to make a difference. The fluid doesn't do much lubricating in any case, it is just a 10w oil, so the most critical thing is that it flows properly. That is a non-demanding application for a fluid.

What happens is that deposits and varnish form in the transmission from age and heat. They are essentially baked in place. When you put in a new fluid, which has a high level of detergents by design, it cleans out all those passages. It then moves that crud, and can cause blockages in the valve body, solenoids, actuators, etc. It goes from where it wasn't hurting anything, to where it causes bad shifting by blocking flow. The new fluid is essentially a powerful cleaner.

BMW says not to change it because the balance of costs of changing it vs any benefit in increased transmission life, isn't positive according to their calculations. It doesn't matter who is paying those costs.

If you change it often, from new, then there is never much of a chance for deposits to build up. That makes it safer, overall. However, it doesn't address the question of whether the old fluid is hurting anything, it just means that changing it has less risk.

It is your decision. However, many here would not touch it at 150,000 miles and with no problems evident. Others would do it. There isn't a single right answer.

[sockethead]

Originally Posted by JCL

The material that you take out of the pan, which most term 'sludge' is actually sitting on the dirty side of the filter, not hurting anything. If the filter is clogged, then that is a problem. However, the junk usually just sits in the bottom of the pan below the filter.

Parts don't break down with age. There are no higher pressures or stresses on the springs or valves. The fluid does deteriorate with age, as it oxidizes, but the question is whether that is enough to make a difference. The fluid doesn't do much lubricating in any case, it is just a 10w oil, so the most critical thing is that it flows properly. That is a non-demanding application for a fluid.

What happens is that deposits and varnish form in the transmission from age and heat. They are essentially baked in place. When you put in a new fluid, which has a high level of detergents by design, it cleans out all those passages. It then moves that crud, and can cause blockages in the valve body, solenoids, actuators, etc. It goes from where it wasn't hurting anything, to where it causes bad shifting by blocking flow. The new fluid is essentially a powerful cleaner.

BMW says not to change it because the balance of costs of changing it vs any benefit in increased transmission life, isn't positive according to their calculations. It doesn't matter who is paying those costs.

If you change it often, from new, then there is never much of a chance for deposits to build up. That makes it safer, overall. However, it doesn't address the question of whether the old fluid is hurting anything, it just means that changing it has less risk.

It is your decision. However, many here would not touch it at 150,000 miles and with no problems evident. Others would do it. There isn't a single right answer.

This is about what I was going to say... leave it sealed.

BMW mechanics make a lot of money off a trans job but most have a conscience and the experience to back it up when they say leave it alone ... being a mechanic for over 30 yrs. myself, I'd agree with them.

[Quicksilver]

Originally Posted by Mudnyrey

My 2004 has 156k miles on it and it runs and shifts strong. Should I get the Trans Fluid & Filter changed? or should I just leave it be?

At this point, If it ain't broke don't fix it....

[Mudnyrey]

JCL -
In the area of "Flow" is what I was generally thinking of "if" the filter was replaced, would help in the flow of the fluid and removing any "Sludge" that has built up over time in the bottom of the pan as well as what the filter may have caught. (Pro-Active) However could cause more harm by initiating then just leaving it alone.

But given what I have reviewed, and questioned in the past regarding another vehicle, I wanted more clarification and understanding of the Pro's and Cons. Preventative Maintenance is important, however this understanding sheds better knowledge of the potential hazard verses either could impose over time.

Your insight is greatly appreciated. I totally agree regarding the cost of not changing the trans fluid verses the benefits of increasing the life of the transmission by changing the fluid and the possibilities it may interrupt and potentially cause issues that other wise could have been avoided if left alone, without any issues in the first place, or it would be suggested not to change it.

I won't be changing my fluid BTW.

Thanks
~Mud

[goldenbird]

Don't change the fluid. Leave as is. Friends gave you nice answers. That's my opinion too.