Let's talk Transmission Maintenance...

[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

[Lambeau]

Originally Posted by JCL

OK, I'll bite to start it of. Carrying on the discussion from previous posts....

My lack of support for changing the fluid is not because "BMW said" but rather because I see little benefit to changing it, and a small but real risk. The risk of damage is slight, but it exists. At the same time, I think that the transmission is likely to fail from non-fluid related causes prior to the fluid degrading to the point that it causes a transmission failure itself.

The risk of transmission fluid changes that I refer to is not due to power flushing, which I wouldn't do. It is simply from draining and filling.

If owners do change it, I would use BMW recommended fluids (no aftermarket fluids), a new filter, and a very careful adherence to the BMW procedure for getting the correct amount of fluid in it, using a thermometer to determine fluid temperatures while setting the level.

Originally changed my filter/fluid at about 100,000 miles and yesterday at 173,000 changed just the fluid. Again used Pentosin NOT recommended BMW fluid. Have towed heavy trailers many miles (to Alaska & back & across country) and with the DPF/EGR delete and the extra power associated, I've really put this trans to the test with zero issues. Change the fluid, don't listen to the doomsday folks as they most likely own BMW stock and want to help ensure early transmission failure and replacement.

[ard]

Originally Posted by JWoody

HHhhhmmm, this is a good point. My MKIV VW GLI is a daily driver with a 6SPD manual tranny, but I do 40K tranny oil changes with AMSOil. I believe in what BMW says for their vehicles, but I am considering doing 50K Tranny changes for our X5. But I plan to use BMW's oil vs AMSOil. Just my .02...

-J

Manual trannies are a whole different kettle o fish...IMHO

A conventional manual has no hydraulic circuits, no clutches in the fluid path, relatively low heat...fluid will last quite some time. In my M5 and 996TT I've done tranny and differential changes and the fluid is surprisingly good even at a 50k change interval. (I even wasted my money on a Used Oil Analysis on the tranny fluid at 50k in the bmw..fine, but stabilizers getting 'thin')

A

PS I wholeheartedly believe in OE fluids for changes, especially in warranty. I don't really buy into any of the 'lubricant hype' that red/roy/ams/etc is a 'better' race oil/whatever... give me frest factory fluid at decent intervals (unless it really is a race car )

[killcrap]

here is the scoop. your car is a bmw equipped with CBS. Condition based Service. Every 8th Oil Service, the Transmission is serviced, so it is not 100,000 miles. It can be 70k miles if you drive it hard, and 120k miles if you drive it soft. Second, the x5 transmission is equipped with a Plastic Trans Pan, over the course of owner ship, this pan will start leaking, most likely the sealing sleeve is leaking for the mechatronics connector. Most leaks occur at 30k miles. In which during repair your fluid will be replaced if the fluid is dirty.

[JCL]

Originally Posted by killcrap

Most leaks occur at 30k miles. In which during repair your fluid will be replaced if the fluid is dirty.

Does BMW still recommend draining the old fluid and putting it back in for certain repairs?

[ard]

Originally Posted by killcrap

here is the scoop. your car is a bmw equipped with CBS. Condition based Service. Every 8th Oil Service, the Transmission is serviced, so it is not 100,000 miles. It can be 70k miles if you drive it hard, and 120k miles if you drive it soft. Second, the x5 transmission is equipped with a Plastic Trans Pan, over the course of owner ship, this pan will start leaking, most likely the sealing sleeve is leaking for the mechatronics connector. Most leaks occur at 30k miles. In which during repair your fluid will be replaced if the fluid is dirty.

Quoted FROM THE MAINTENANCE MANUAL:

"Automatic transmission (not shown in
CBS)
Maintenance work:
 Replace ATF at intervals of 100,000 miles."

So not in the CBS, and yes 100k miles.

How they can 'replace fluid at 30k if dirty, but not recommend any service nor even inspection of fluid is laughable.

[Price]

BTW, when did BMW previously said "lifetime"? I owned '02 325 and the manual stated 100K interval. I recall this since I owned an Audi too at that time which had quite similar ZF tranny, and Audi claimed lifetime.

Also, aren't the sevice interval is determined nowadays just by the total of gas/diesel consumed?

[JCL]

BMW has used both 100,000 miles, and lifetime, recommendations for transmission fluid changes. What has changed is the application, the transmission design, the fluid, BMW's experience with fluid changes, and various extended service plans. What we don't know is how much each of those factors influenced BMW's recommendations.

The service intervals have a baseline, and then are adjusted by things such as fuel consumed. They are also using sensors that directly measure oil condition now. This is all for engine oil change intervals, more than for other fluid intervals, as I understand it.

[Price]

Originally Posted by JCL

The service intervals have a baseline, and then are adjusted by things such as fuel consumed. They are also using sensors that directly measure oil condition now. This is all for engine oil change intervals, more than for other fluid intervals, as I understand it.

That's the thing: it used to be this way (mileage would be substracted from the service interval @ double rate for period when engine temp < certain degree), but I believe in all recent bimmers it's straight consumption, and nothing more. For US E46 it's 667 gallons, iirc.

[JCL]

Originally Posted by Price

That's the thing: it used to be this way (mileage would be substracted from the service interval @ double rate for period when engine temp < certain degree), but I believe in all recent bimmers it's straight consumption, and nothing more. For US E46 it's 667 gallons, iirc.

Originally Posted by ard

I know of no specific "oil condition sensor". Generally it is based on total Liters of Fuel Consumed.

This is a description of the oil quality sensor that BMW started using in 2005 or 2006 on the N52. Current parts books show the same part number, so I suspect it hasn't changed. Oil additive depletion is calculated via capacitance changes in the oil. It isn't a complete measure of oil quality, but simply one more factor for the DME to add into the distance to change calculation.