A Question on Much Discussed Topic Here...Transmission Fluid Change

[Skier1]

Below is an extract I had sent through from ZF Transmissions list of lubricants .

5-, 6- and 8-speed as well as 4HP20 automatic transmissions:
ZF 5-, 6- and 8-speed as well as the ZF 4HP20 automatic transmissions are filled maintenance-free with specially developed partially
synthetic ATF oils. Maintenance-free fills are intended for normal operating conditions. Especially driving at very high operating
temperatures can result in accelerated aging or increased wear of ATF oils. It is recommended, in the event of severe operating
conditions, such as:
- frequent highway driving in top speed range,
- offensive, sporty driving style,
- frequent trailer operation,
being above average, oil purification (oil change) on automatic transmissions is recommended between 80,000 km and 120,000 km, or
8 years, depending on the load.
In each case, only released ATF oil may be used for oil changes. And oil changes must be performed in accordance with the relevant
specifications.

[OptimusPriM5]

Originally Posted by Skier1

Below is an extract I had sent through from ZF Transmissions list of lubricants .

5-, 6- and 8-speed as well as 4HP20 automatic transmissions:
ZF 5-, 6- and 8-speed as well as the ZF 4HP20 automatic transmissions are filled maintenance-free with specially developed partially
synthetic ATF oils. Maintenance-free fills are intended for normal operating conditions. Especially driving at very high operating
temperatures can result in accelerated aging or increased wear of ATF oils. It is recommended, in the event of severe operating
conditions, such as:
- frequent highway driving in top speed range,
- offensive, sporty driving style,
- frequent trailer operation,
being above average, oil purification (oil change) on automatic transmissions is recommended between 80,000 km and 120,000 km, or
8 years, depending on the load.
In each case, only released ATF oil may be used for oil changes. And oil changes must be performed in accordance with the relevant
specifications.

Lol...love the 2nd bullet.

[e30cabrio]

Originally Posted by JCL

Never claimed it didn't degrade. Just that it degrades so slowly that something else unrelated to fluid quality will fail before it becomes a problem. That is why the transmission was designed to adapt to changing fluid viscosity over time.

It isn't rocket science at all. It is reliability engineering. If changing the fluid early was shown to extend the life of the transmission then it could be considered a PM activity. If it hasn't, then it isn't preventative maintenance, it is just service work.

Conversely, if it required changing at any specific interval, 100 k or whatever, then exceeding that spec would result in transmissions grenading for reasons traceable to fluid breakdown. We wouldn't be seeing 200k and 300k examples running fine on the original fluid.

Who said anything about early? I am talking about 10 years & whatever miles. Most at this point are at or near 100k, many well over. Regardless, in my case I decided 11 years was enough and did the filter & oil that came out (6 liters) and then what came out of the pan (3 liters) After both, I have no issues yet. It is a total of about 8500 miles.

I am not saying anyone need do anything, I am saying fluids degrade, systems need care & I chose to proactively care for my property.

If this conversation were taking place in the F15 forum about a 20k car that would be early, here with cars that have an average of 130k, not so much.

[srmmmm]

I'm sticking with my plan of no fluid changes until the unit mis-functions. At that point I'll install a remanufactured unit. I've seen my model at about $2500 with a three year warranty.

2002 X5 3.0 258,858 miles on original fluid
2004 325i 115,000 miles

[StephenVA]

Originally Posted by OptimusPriM5

Lol...love the 2nd bullet.

That B U!!!

[OptimusPriM5]

Ok guys one more thing but not a process or part question. I read in one of the many many threads someone posted a shot of the transmission tag - the green metal looking thing thats tagged as a ZF at least on my model. I forgot what it was used for but I saw mine this evening and it showed a bunch of numbers but there was one I remembered that was important. It was the one that was preceded by a number of 0's. Mine is 0000034.

Can someone refresh my memory what the significance was to that number? Again this is for an 02 4.6 I know the transmission is A5S440Z from spec sheet. What is the significance of that number preceded by all the 0's? I remember there was some distinction made.

Thanks in advance guys!

[JCL]

The 34 version was a slightly beefed up version of the 29 model of the 5hp24 transmission used on the 4.4, and is specific to the 4.6

Larger torque converter and an extra clutch plate, IIRC. RRPhil posted the details here if you search.

[OptimusPriM5]

Originally Posted by JCL

The 34 version was a slightly beefed up version of the 29 model of the 5hp24 transmission used on the 4.4, and is specific to the 4.6

Larger torque converter and an extra clutch plate, IIRC. RRPhil posted the details here if you search.

Thanks so much. Thats the post I was looking for!