Let's talk Transmission Maintenance...

[JCL]

Originally Posted by FSETH

At the end of the day, do what makes you happy. Just dont think that changing the fluid is going to prevent trans failure and realize that there is a small risk in doing so. It is not always that new fluid = better in an auto trans.

I can fully support this. There are real benefits (of the 'feel good' variety) in working on a vehicle, and there is nothing wrong with doing some small project to increase the feel good factor. I change my own brakes and put my winter tires on, not because I can't afford to pay someone else, and not because my work is any better than another mechanic's, but simply because I like working on my vehicle and these are two of the few things left to do at home on a nearly new vehicle.

[ard]

Originally Posted by FSETH

T. I bet it isn't that much over 100k. BMW probably doesn't see any reason to recommend changing the fluid before that mark because they know that the original fluid will last the average trans lifespan anyway.

And my entire point is that fluid degradation is part of the cascade that leads to transmission failure- that in an internally lubricated mechanical/hydraulic assembly, the fluid must be considered a wear component.

I do not understand how one can say "The transmission failed at 150k, but it wasn't due to not changing the fluid for 10 years, the parts just wore out"

I wonder if the average lifespan would increase if we had an ATF change at say 40k intervals?

I believe it would increase.

Others here are convinced there is no benefit.

There is no 'right' answer, yet, according to my research. Anecdotes abound, supporting both sides. Plenty of inferences from manufacturers marketing info and 'recommendations', but no public data from which to draw conclusions. Undeniable historical data supports regular maintenance, but new advances in fluid and transmission design may support extended intervals. Perhaps the discussion is 'how extended'?

A

[FSETH]

Originally Posted by ard

I wonder if the average lifespan would increase if we had an ATF change at say 40k intervals?

I don't know. I wish we could prove that, but I don't think we can. It seems like there are way too many failures of low mileage transmissions for me to think the fluid is a real concern. To me, the people with over 150k on original auto transmissions (new fluid or original) are lucky because BMW automatic transmissions seem to be problematic from very low mileage. Even before 40k miles. I do see your point though, but how do we know if the same thing that failed on the low mileage trans is not the same reason that one failed at 125k? Regardless of fluid condition? Also, will the new fluids additional benefits (if any) be worth any risk of changing it?

I am no expert, but aren't most of the trans failures (low or high mileage) related to items not necessary affected by fluid, or atleast not due to worn fluid no longer capable of doing it's job?

Has anyone here who has experienced a trans failure for any reason had the transmission professionally analyzed? Would be interesting to see the results from a few failed transmissions with and without fluid changes.

[Quicksilver]

What I find curious is that if transmissions failures are the big issue
that some have reported them to be, then why has there been
no recall of the vehicle based on complaints by the owners?

If in fact this is an industry wide issue with the X5 then shouldn't
someone file a class action suit seeking correction and compensation?

[JCL]

They really aren't a big issue, IMO. Most of the people discussing this issue in this thread haven't had a transmission failure. Transmissions get lots of discussion on this and other boards, but that is about transmissions not meeting owner's expectations of lasting the vehicle life, not about warrantable failures or safety issues. If BMW dutifully fixes transmissions that fail during the warranty period, then what would the basis of a class action suit be?

It is usually a safety issue that prompts a recall.

[Lubehead]

I thought I should reply to ard's comments;

What does "well served" actually mean?

By that I mean to infer that the results of their (ZF's) recommendations do not create a negative perception of the company or its products.

Do you mean that ZF believes the longest service life will be achieved by not ever changing the fluid?

No, I did not say that and with the aforementioned 100k recommened change interval, evidently ZF does not either.

Or has this become a calculus of 'ownership costs' and 'owner hassle' and 'likelihood of trade in' combined with odds of failure to determine this is 'best'?

Isn't that suggesting a planned or expected failure rate? I cannot answer that but certainly don't subscribe to it.

I'd like to think ZF & BMW have ONLY the longevity of the AT assembly as their sole determinant as to the fluid service. Until that is confirmed, I thin the community is ill served by broad assertions that 'high tech' fluids will save the day.

To me it's the sum of the parts (the lubricant being a part) that allows the recommendations to be made. It isn't about a "high tech" fluid, rather it's about the total system design. No broad assertion regarding fluid quality.

In regards to my suggestion for an oil sample valve you asked;

Personally I suppose I agree, but I need to ask you "why?" Isn't the BMW interval of 100,000 miles satisfactory?

m5james post suggests that driver actions are a contributing factor to transmission and other component life. He also states that he adheres to routine transmission fluid changes as a matter of what he (and you and others believe) to be effective in providing longer transmission life. And while I do in fact agree, the difference I would suggest is that by having an oil sample valve, one could in fact determine the appropriate drain interval for a specific transmission driven by a specifc owner in a specific environment.

We always want to change good fluids as opposed to changing fluids that are deteriorated which as m5james states

there is absolutely NO fluid that doesn't degrade over time. Period.

The challenge is knowing when to change the fluid to achieve the elusive maximum transmission life goal. Without analysis, fluids may be changed prematurely, or perhaps, (I can only surmise) just before they dramatically degrade, assuming the 100k recommended change interval is in fact based on engineering or empirical evidence which suggests it is the most appropriate interval for the majority of applications.

And thanks to JCL for the Maintenance Management document.

Great thread!

[ard]

Originally Posted by Lubehead

Great thread!

I'll agree there!

I too found JCLs paper of interest.


In particular it highlights the need to ensure that the stakeholders and customers understand the extent to which they share the same goals/needs, and - particularly- when their needs diverge.

When you have such a nebulous concept of 'overall customer satisfaction' that drives a decision on "how long does a tranny need to last" one may find their answer ("as long as possible") might not be the same as the manufacturer has determined....

If a manufacturer uses concepts such as 'overall maintenance costs', and 'our responsibility is only to the first buyer- second buyers are not our customers' it becomes a bit trickier to understand the genesis for the assumptions underlying their recommendations.

A

[JCL]

I am glad people found the paper interesting. Yes, it is an interesting thread.

Lubehead: with a user name like that, you should give us some of your background; I suspect it is relevant to the discussion.

ard: I knew you would like the maxims at the end of the article. Yes, different stakeholders have different objectives. In reference to BMW's objectives, overall I think they likely parallel ZF's in providing maintenance recommendations: neither wants their good name besmirched. They both have a brand to protect. I don't subscribe to the hype around marketing driven reductions in prepaid maintenance costs, as I see little public pressure on those maintenance costs. In reference to the paper, I would be interested in your thoughts on maxim #4 (most failures are not more likely to occur as equipment gets older) and maxim #7 (the frequency of condition-based maintenance tasks should be based on the failure develoment period, or lead time to failure). These two points do not support following a preset fluid change interval in the hope that it will reduce transmission failure rates. They do support monitoring the fluid condition; my question then is what the criteria will be for flagging a problem fluid (apart from the obvious, such as water contamination). I don't believe we have specs for the friction modifiers in the fluid, which are being depleted over time. We could certainly measure viscosity, and trend it.

Jeff

[MRV99]

I have a few quick comments. I know I don't post much but I have built my fair share of trans, diffs, and engines.

1) BMW new maintenance recommendations are based on a few factors. Govt pressure to reduce waste, BMW paid maintenance...

2) A CEO of a global manufacturing companies made a comment to me and my family while vacationing together. "If we build them to last like we used to we would run out of customers to sell our products to and our stock holders will not have that" This is a direct quote so I will not argue it. Believe me this company used to build items that would last a good 20-30 years but not anymore.

3) All mechanical parts wear with use and all fluids no matter how synthetic they are made break down. I have never taken apart a transmission or diff that does not have some metal shavings or wear that has occurred. If you think that ZF makes transmissions which are sooooo superior that they never need fluid change or better yet 100k changes well then they should never have a problem going out of business. I will bet that any trans will show wear even at 15k miles. I have had many conversations with techs outside the BMW shop and the ones that have been doing this for 15 years will say BMW new maintenance schedule is for car turn over and does cause the cars to prematurely fail.


Last and not least. Globalization has caused manufactures to build an item just good enough to survive and not last. Hahaha who ever heard of a plastic oil pan.....

[JCL]

Originally Posted by MRV99

Hahaha who ever heard of a plastic oil pan.....

Expect to see lots more plastic oil pans. They have been used successfully on truck engines, and are being developed now by many suppliers. Plastic intake manifolds paved the way. May be a while until we see another full plastic engine block... Just to add fuel to the fire, the supplier of the pan in the photo is reportedly integrating a lifetime oil filter. That should go over well.