Tranny / differential fluids - when to change?

[nicknaz]

Originally Posted by tranquility

I was planning on a tranny fluid change 160,000kms/100,000miles.
.

If you weren't planning to change it for another 28k miles anyway, it seems ok. I don't see why they wouldn't just put in the new oil (unless you are no longer under warranty and didn't want to pay for oil??? or ???) but at the same time if they used a clean container to capture and refill, I don't see why you would be any worse off than you were before.

By the way, I didn't read that the first time. That seems a bit odd they wouldn't just change it with new oil.

I was referring to the fact you should make friends with your tech so they will be more likely to speak up about "judgement calls" (i.e. replace gearbox oil or reuse because it is "lifetime fill")

[tranquility]

Originally Posted by nicknaz

If you weren't planning to change it for another 28k miles anyway, it seems ok. I don't see why they wouldn't just put in the new oil (unless you are no longer under warranty and didn't want to pay for oil??? or ???) but at the same time if they used a clean container to capture and refill, I don't see why you would be any worse off than you were before.

By the way, I didn't read that the first time. That seems a bit odd they wouldn't just change it with new oil.

I was referring to the fact you should make friends with your tech so they will be more likely to speak up about "judgement calls" (i.e. replace gearbox oil or reuse because it is "lifetime fill")

I've long been out-of-warranty and this tranny issue just sprung up during servicing because they detected a leak. I have no idea how much it would have cost to have new tranny fluid but I suppose that they wanted to make sure that the leak was fixed before me spending $$$ so that's probably why they didn't even suggest buying new fluid. (Btw, any idea how much tranny fluid costs?)

Yup, I should've asked more in-depth w/ the tech. Too many things happening that day, will give him a shout later on. Thx for the reminder.

[jannisa]

I suggest you purchase 2 liters (our diff contains 1,2lt fluid) of synthetic 75w90 gear oil for non limited slip diffs (''ns'' is the acronym by many manufacturers, i.e. no slip). The oem fluid is made by castrol but there are so many alternatives out there. It's as much as 25 euros over here for 2 liters. I change it every 30.000km and I can pretty much ensure you that even in that mileage the fluid is shockingly black. So much for lifetime fluids. If you intend to keep your car I also suggest you plan at some point to change the dct oil pan and fluids and do this at the dealership only as it gets very tricky. This will set you back around 600$ unfortunately.

[jparnes1]

Can someone direct me to the CBS intervals for our car? The iDrive doesn't list everything (no plugs, air filter, etc...) and I'd like to know what's coming up without going in for a key read.

[jannisa]

Air filter 20.000km
Cabin filter 20.000km/annually whichever comes first
Brake fluids every 2 years dot4 only
Cooling system flush every 3 years. Mixture of bmw fluid with tap water (not distilled according to bmw, a long conversation)
Fuel filter practically longlife, it's located in the tank
Spark plugs every 60.000km on N54. Every 30.000km if tuned (this is the official strategy for other platforms with N54 that have the performance package). That means 35iS vehicles should change spark plugs every 30.000km.
There is no particular plan for differential and transmission fluids, the longlife label policy. I have found out that on 30.000km the diff fluid looked very-shortlife, I didn't taste it though, it was too black. My personal plan is to change the diff oil every 30.000km, dct oil pan and fluids at around 60.000-80.000km (still way to go in my case) and engine oil every 5.000km. Regarding engine oil I have used so far castrol 5w-30, 5w-40 and 0w-40 and I will stick with 5w-30 because it keeps temperature a bit lower than the other options. Will try Fuchs Titan 5w-30 next time though.

[nicknaz]

Guys, two links that might be useful. a DCT service kit and slightly discounted quarts of the DCT factory gear oil


DCT Service Kit
http://www.ecstuning.com/BMW-E92-M3-...ain/ES2677651/

DCT factory fill gear oil

https://www.getbmwparts.com/parts/20...?siteid=214672

[tranquility]

Ok guys, thx for all your advice thus far. I'm still waiting for feedback from you that have actually changed their tranny and/or diff fluids. I think that only jannisa changed his diff fluid 30,000kms/18,000miles. My mileage is at a high 116,000kms/72,000miles and I haven't changed either.

I finally heard back from the tech that inspected the tranny fluid during the leak issue and supposedly he said that it was in "excellent" condition. I'm still amazed by that. I should've asked him to take a photo when he was at it but alas. The responses from the various dealers I've discussed w/ have not be helpful, virtually all of them toe the line and insist that both fluids are lifetime, only one suggested to change the diff fluid 120,000kms/75,000miles. I'm still planning to change my tranny fluid 160,000kms/100,000 miles...not idea when to do the diff fluid.

Anyway, if anyone has real-life experience changing either fluid, I'd love to hear from you. Thx in advance.

[nicknaz]

Originally Posted by tranquility

Anyway, if anyone has real-life experience changing either fluid, I'd love to hear from you. Thx in advance.

First off, I have not and definitely will not be changing DCT or differential oil since I'm 4-10 months away from lease end, depending on what pull ahead programs are out this December. As far as I am concerned, lifetime is 36mo/30k miles for this car....

When I DID care about this on my last "keeper" (a WRX) I used factory fill gear oil only, did first gear oil change at 15k mile (as per "Severe service" maintenance schedule) and did a used oil analysis to assess future gear oil change intervals.

Hope that helps....

[tranquility]

This is a silly question, but I assume that the brand/type of tranny and diff fluids used have not changed from before and since BMW moved over to the 'lifetime' policy?

[nicknaz]

I believe the list of approved oils gets updated regularly (and no one believes that the oils are lifetime... it is just that many (like me...) choose to ignore the need to change because the car won't be kept for long enough to matter)

For the DCT, I think it has only ever been that Pentosin oil on approved list

[jparnes1]

Originally Posted by nicknaz

First off, I have not and definitely will not be changing DCT or differential oil since I'm 4-10 months away from lease end, depending on what pull ahead programs are out this December. As far as I am concerned, lifetime is 36mo/30k miles for this car....

No offense Nick, I would do the same if I leased, but this is why you should never buy an off-lease car.

[jparnes1]

Originally Posted by tranquility

This is a silly question, but I assume that the brand/type of tranny and diff fluids used have not changed from before and since BMW moved over to the 'lifetime' policy?

True. Nothing has changed other than BMW's desire to minimize their in-warranty costs. It used to be that you couldn't change the engine oil enough...

[jparnes1]

Originally Posted by tranquility

Ok guys, thx for all your advice thus far. I'm still waiting for feedback from you that have actually changed their tranny and/or diff fluids. I think that only jannisa changed his diff fluid 30,000kms/18,000miles. My mileage is at a high 116,000kms/72,000miles and I haven't changed either.

I finally heard back from the tech that inspected the tranny fluid during the leak issue and supposedly he said that it was in "excellent" condition. I'm still amazed by that. I should've asked him to take a photo when he was at it but alas. The responses from the various dealers I've discussed w/ have not be helpful, virtually all of them toe the line and insist that both fluids are lifetime, only one suggested to change the diff fluid 120,000kms/75,000miles. I'm still planning to change my tranny fluid 160,000kms/100,000 miles...not idea when to do the diff fluid.

Anyway, if anyone has real-life experience changing either fluid, I'd love to hear from you. Thx in advance.

What kind of feedback are you looking for? I change my fluids much more often then BMW suggests (engine 5K, diff and MT 30K, coolant x 2 years, brake fluid x 1 year), but I can't give you any science behind that. I do it because that's my comfort level.

[tranquility]

Originally Posted by jparnes1

What kind of feedback are you looking for? I change my fluids much more often then BMW suggests (engine 5K, diff and MT 30K, coolant x 2 years, brake fluid x 1 year), but I can't give you any science behind that. I do it because that's my comfort level.

I guess I want to know what the fluid condition actually is for those that did the fluid change, to see if really necessary at those intervals.

[jparnes1]

Originally Posted by tranquility

I guess I want to know what the fluid condition actually is for those that did the fluid change, to see if really necessary at those intervals.

The only way to answer your question us by doing and oil analysis, but this will show different results based on the car (30i vs. 35i), tuned vs. stock and driving habits. It's the only objective way to figure out your maintenance intervals.

[nicknaz]

Originally Posted by jparnes1

No offense Nick, I would do the same if I leased, but this is why you should never buy an off-lease car.

None taken! I'm just following manufacturer's orders after all

[tranquility]

Originally Posted by jparnes1

The only way to answer your question us by doing and oil analysis, but this will show different results based on the car (30i vs. 35i), tuned vs. stock and driving habits. It's the only objective way to figure out your maintenance intervals.

Hmm, that's a good point, which leads to my next question if anyone has done that then.

[jparnes1]

Originally Posted by tranquility

Hmm, that's a good point, which leads to my next question if anyone has done that then.

Tranquility, the point I was trying to get across is if you're looking to do more frequent maintenance, you can't go by other's oil analysis to determine what's good for you. Run your engine oil for X miles, send it in and see what the analysis says for your car and your driving habits. Try www.Blackstone-labs.com.

[tranquility]

Originally Posted by jparnes1

Tranquility, the point I was trying to get across is if you're looking to do more frequent maintenance, you can't go by other's oil analysis to determine what's good for you. Run your engine oil for X miles, send it in and see what the analysis says for your car and your driving habits. Try www.Blackstone-labs.com.

Thx, I realize that. Unfortunately, I don't have access to the various fluids by myself and might as well change them instead of having a shop do an analysis for me. Just wondering if someone did the analysis/at what interval so I can get at least a ballpark range. I dunno...

[nicknaz]

Originally Posted by tranquility

Thx, I realize that. Unfortunately, I don't have access to the various fluids by myself and might as well change them instead of having a shop do an analysis for me. Just wondering if someone did the analysis/at what interval so I can get at least a ballpark range. I dunno...

How it works is that you do the first oil change whenever you feel like it, then you give the shop a bottle to fill up with the used oil (or you fill it yourself if you are doing the oil change yourself) and then you mail the bottle to blackstone labs along with $65 for the analysis.

You get a printout back with wear metals found in the oil, the viscosity of the oil and the amount of additives less. Blackstone labs make a recommendation and say things like "based on the level of additives and the viscosity you could have used this oil for another X miles, or you should have changed it Y miles ago. Then you account for that recommendation the next time you do the change.

In the absence of any members doing oil analysis on their DCT gear oil, you can use the "old school" interval of every 15k miles for ATF or 30k miles for manual gearbox and differential (either way, you are overdue, as per this line of thinking)

EDIT: removed link

[tranquility]

Originally Posted by nicknaz

How it works is that you do the first oil change whenever you feel like it, then you give the shop a bottle to fill up with the used oil (or you fill it yourself if you are doing the oil change yourself) and then you mail the bottle to blackstone labs along with $65 for the analysis.

You get a printout back with wear metals found in the oil, the viscosity of the oil and the amount of additives less. Blackstone labs make a recommendation and say things like "based on the level of additives and the viscosity you could have used this oil for another X miles, or you should have changed it Y miles ago. Then you account for that recommendation the next time you do the change.

In the absence of any members doing oil analysis on their DCT gear oil, you can use the "old school" interval of every 15k miles for ATF or 30k miles for manual gearbox and differential (either way, you are overdue, as per this line of thinking)

Old school here:
EDITED

Thx for your explanation. So they only do engine oil analysis (+gear oil) but not differential? I glanced at their sample reports, it's extremely technical and doesn't have the info that you stated as an example in your post...do they dumb it down so that laymen like me can understand what's going on?

Thx, I have a copy of the old school maintenance sch also. I've read that apparently in our case perhaps the old school intervals are much too short, but no idea if that's correct or not.

[jparnes1]

Nick, FWIW, Mike Miller requests that his maintenance schedule not be posted on the internet. It's copyrighted and periodically updated.

Tranquilty, Blackstone will test any oil in your car. The report is technical but their results and recommendation are written clearly.