Let's talk Transmission Maintenance...

[DSE]

I generally follow the "old school" maintenance schedule of Mike Miller of BMW CCA. He describes BMW automatic transmissions as the "bane of my existence."

For older automatic transmissions (i.e., before there was a "lifetime" or 100,000 change interval), he recommends Red Line ATF changes every 30,000 miles, or every 15,000 miles with regular ATF fluid.

For newer transmissions (which applies to all X70s), he advocates changing the auto transmission filter and fluid every 60,000 miles, using BMW's proprietary ATF.

If you are A BMW CCA member, email him for a free copy of his old school maintenance schedule. It is a very interesting and a fun read, and there is more discussion on this issue. (If you are not a member, you should be).

[FSETH]

Originally Posted by DSE

I generally follow the "old school" maintenance schedule of Mike Miller of BMW CCA. He describes BMW automatic transmissions as the "bane of my existence."

For older automatic transmissions (i.e., before there was a "lifetime" or 100,000 chnage interval), he recommends Red Line ATF changes every 30,000 miles, or every 15,000 miles with regular ATF fluid.

For newer transmissions (which applies to all X70s), he advocates changing the auto transmission filter and fluid every 60,000 miles.

If you are A BMW CCA member, email him for a copy of his old school maintenance schedule. It is a very interesting and a fun read. (If you are not a member, you should be).

I was wondering what his opinion was on this. I am a member, but have yet to e-mail him for the service schedule.

[ripp222]

This is an older thread, but a good one.
It's always interesting to see what BMW puts in their Service Training Literature...

ST057 Electronic Transmission Control (January 2003) / Electronic Transmission Control P2

Transmission Fluid Information
Transmission Fluid (Oil)
The automatic transmission provides filtered, pressure regulated hydraulic fluid for all of the transmissions functional requirements. All BMW automatic transmissions are designed to operate with specific fluids. Use of non-approved oil will cause malfunctions and irreparable transmission damage which is not covered by BMW warranty.
The transmission fluid provides the following functions:
• Lubricates mechanical components (planetary gears, bearings etc.).
• Removes heat and transfers heat to transmission cooling system. (Heat Exchanger).
• Removes debris and contaminants to sump and filter when circulated.
• Provides a transfer of kinetic energy in the torque converter.
• Allows hydraulic operation of mechanical components (clutches, brakes) via control of the valve body.
Also, transmission fluid has various properties to prevent oxidation and breakdown from heat and friction. Each type of transmission fluid has properties specific for each transmission application.
Fluid level is crucial in the proper operation of an automatic transmission. Improper fluid levels will cause improper operation and eventually irreparable transmission damage.
Improper fluid level can cause:
• A low fluid level can cause an interruption in oil flow during fast acceleration or hard braking which can cause gear shift malfunctions and noises.
• An excessively high fluid level can cause the rotating mechanical components to paddle in the oil. This produces foam which introduces air into the hydraulic system.
• A low fluid level can also cause transmission overheating causing premature transmission failure.

[PHOTO]

Transmission Fluid Checking Procedures
Transmission fluid checking is accomplished using the DISplus or GT-1. The DISplus or GT- 1 is used to monitor transmission fluid temperature to insure the transmission is not over or under-filled. As with most other current ZF transmissions there is no dipstick, the fluid level is checked and filled at the fill plug. The location of the fill plug varies between transmissions.
Transmission fluid should be checked between 30 and 50 degrees Celsius (unless otherwise specified). Use the DISplus and/or GT-1 to determine transmission temperature. The transmission temperature information can be found in the diagnosis section under Service Functions.
Proper procedures for checking and filling transmission fluid can be found in BMW Service Information Bulletin B 24 01 98. When checking transmission fluid, observe the following items:
• Transmission in Park
• Parking brake applied
• Engine Running
• Vehicle level
• No engine load
• Trans Temp 30-50C
• Observe correct drain plug torque
• Use correct fluid
When replacing parts on transmissions that use lifetime fluid, drain fluid into a clean container and reuse.

[PHOTO]

Transmission Fluid Application
There are numerous types of transmission fluid used in BMW transmissions. With the exception of the early transmissions (4HP22/24, A4S310/270R and the A5S310Z in the E34) all current BMW transmissions use “Lifetime Fill” transmission fluid. There is no maintenance required for these transmissions. It is important to use the correct fluid. Incorrect use of the transmission fluid can cause non-warrantable transmission damage.
When performing repairs on transmissions with lifetime fluid, it is important to drain the transmission fluid in to a clean container for re-use. New fluid should only be used for transmission replacement and for topping off after repairs.
Also, transmission fluid level is vital to the proper operation of the transmission. Refer to BMW Service Bulletin B 24 01 98 for proper fluid level checking procedures.
When servicing or repairing BMW automatic transmissions, refer to TIS for fluid capacities.
For fluid types refer to the “Operating Fluids Manual”.

=====================

There was a SIB notifying the change from "lifetime fluid" to 100,000 mile replacement, but I can't locate it at the moment.

[genew]

Originally Posted by FSETH

I was wondering what his opinion was on this. I am a member, but have yet to e-mail him for the service schedule.

I believe I have read that Mike agrees with JCL..He has seen many transmissions fail after a fluid change that were OK prior. I don't have a link but recall reading that.
Gene

[ard]

Originally Posted by genew

I believe I have read that Mike agrees with JCL..He has seen many transmissions fail after a fluid change that were OK prior. I don't have a link but recall reading that.
Gene

People who listen to BMWs "100k interval" do run that risk!!! If you do regular maintenance, and keep the fluid fresh, you will not have issues...but leave the fluid, allow crud to build up and YES, a transmission that had not yet failed may get crud stirred up by a late-in-life fluid change.

To deduce, however, that the fluid changes should, as a matter of global recommendation, not be done 'because I've seen many where problems happen later' is a pretty lame approach to understanding maintenance, & cause and effect.

Finally, people start noticing sloppy shifts, flaring, tranny noises- all signs the tranny has issues- so they bring it in for a fluid change. "Mike" may indeed see issues after these fluid changes. Did the new fluid 'cause' the failure? Hardly.

And again, I have no doubt that Mike and BMW will recommend simply driving the tranny to failure and then buying a rebuilt as the best overall plan (for BMW)

[FSETH]

Originally Posted by genew

I believe I have read that Mike agrees with JCL..He has seen many transmissions fail after a fluid change that were OK prior. I don't have a link but recall reading that.
Gene

You are correct. The "Old School" maintenance recommends trans fuild and filter on modern BMW's with "lifetime" fluid every 60,000 miles. Also, Mr. Miller did say that he has seen "too many times" where people perform a trans fluid/filter service on a higher mileage, but well shifting transmission, then all of a sudden it begins slipping. I do belienve he said he would take the risk though. He also equates it to the fresh fluid flushing a bit of sludge from an area where it was previously doing no harm.

[FSETH]

Originally Posted by ard

And again, I have no doubt that Mike and BMW will recommend simply driving the tranny to failure and then buying a rebuilt as the best overall plan (for BMW)

I actually don't think Mr. Miller would even recommend buying an automatic/DCT transmission in the first place. Also, his recommendations are not typically in-line with BMW NA's.

[chiefneil]

I recall back on the old Roadfly forums that a BMW transmission engineer actually did post in a thread about this same topic. Anybody else remember that? I went back later and tried to find that post but never could.

Anyway, from what I recall he had very clear reasons for why he (and therefore BMW) did not recommend fluid changes. I can't recall the specifics, but I think it was similar to what JCL said. Basically that they weren't necessary and that changes carried an element of risk. That post influenced me sufficiently that I never bothered to change the fluid on either of my BMWs.

Just to throw out my own anecdotal evidence, those BMWs are/were: 2002 X5 with 110k miles - just traded it in last month. And a 2002 330i with 110k miles still on the original fluid. I hope to keep the 330i a couple more years, so my fingers are crossed.

[ard]

How can they talk out of both sides of their mouths?!?!

They say "100k" after the ridiculous lifetime recommendation...but still say we don't recommend it due to the 'increased risk': Which is it?

It is an easy answer: do it at 30-40k, just a gentle fluid change, and then you'll never risk loosening sludge or what not.

neil- with that many miles I'd be worried too. Do you think they will make it to 200k? With that original fluid? poor next owner

I'd love to get an oil analysis on that 9 year old ATF to see how well it protects.

[chiefneil]

Originally Posted by ard

How can they talk out of both sides of their mouths?!?!

They say "100k" after the ridiculous lifetime recommendation...but still say we don't recommend it due to the 'increased risk': Which is it?

It is an easy answer: do it at 30-40k, just a gentle fluid change, and then you'll never risk loosening sludge or what not.

neil- with that many miles I'd be worried too. Do you think they will make it to 200k? With that original fluid? poor next owner

I'd love to get an oil analysis on that 9 year old ATF to see how well it protects.

Would you expect that a transmission that had it's fluid changed every 40k would easily last 18 years and 200k miles?

Not that I would ever keep a car that long, personally. I've already had my 330i a few years longer than I expected.