Something I feel i HAVE to clear up about transmission servicing.

[Jake10080Guy]

Now if i'm wrong in the slightest, feel free to let me know. But i feel i have to stress this, as it really pains me in the head to see guys do this:

If you can- Whenever you're servicing a transmission, don't just change the fluid- you HAVE to more importantly the filter as well.

Because i see people talking about how every so often they change the ATF, but they don't mention anything about servicing the filter.

Realize when your automatic transmission vehicle drives down the road and changes gear to gear, clutch material from the automatic clutch packs, sheds off and goes to the transmission filter. Debris in other words.

Example: While you may change your ATF once at 30,000 miles- then again at 60,000 miles. And so on and so forth. You make it to 90,000 miles and you proceed to drain and fill. You go "Wow i have new ATF, what a relief!" But you still have 90,000 miles of debris in the filter from when the vehicle was new. Eventually your filter clogs up, the automatic transmission oil pump can't build enough fluid pressure to pump through the filter, your automatic clutch packs start slipping and overheating. Soon you'll need an overhaul.


Now i'm not sure what you'll do in the following scenerio- Some Automatics (I think the 8F35 unit in the Bronco Sport counts too) have a non-servicable filter where you have to split the case apart to get in it. I'm not sure what you'll do then. But if you are able to change your transmission filter easily, i stress that it's REALLY important before it clogs up.

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[Bucko]

I'll add to this that simply dropping the pan to change trans fluid IS NOT a fluid change. More fluid in the torque converter is not removed this way.

It requires a low pressure pump to do a complete fluid change. The good transmission shops drop the pan, change the filter, then use a low pressure system to evac all the fluid while pumping in new fluid.
This method is not damaging as some of the myths state on some forums. If you are worried about dislodging contaminants in the transmission, its already a case for rebuild anyhow.

I've been doing this in all my vehicles for over 30 years without fail.

Find a good transmission shop.

 

[Mark S.]

I would follow manufacturer recommendations. Changing transmission fluid filters is can be a fairly intrusive procedure, often requiring disassembly of major transmission components. As you note, it requires "cracking" the case on the transmission in our vehicles. That kind of maintenance introduces it's own type of risk--specifically that something won't be properly reassembled.

Manufacturer recommendations balance the various risks involved--i.e. the risk of a clogged filter vs the risk inherent in intrusive maintenance. I would follow them unless you have a specific reason not to, and by specific I mean an issue based on an inspection, not a generalized recommendation from internet experts.

EDIT: As @Jake10080Guy mentioned below, some transmission filters are easy to change. These are rare in my experience.

 

[Jake10080Guy]

I would follow manufacturer recommendations. Changing transmission fluid filters is a fairly intrusive procedure, often requiring disassembly of major transmission components. As you note, it requires "cracking" the case on the transmission in our vehicles. That kind of maintenance introduces it's own type of risk--specifically that something won't be properly reassembled.

Manufacturer recommendations balance the various risks involved--i.e. the risk of a clogged filter vs the risk inherent in intrusive maintenance. I would follow them unless you have a specific reason not to, and by specific I mean an issue based on an inspection, not a generalized recommendation from internet experts.

Ha, if you know by now some of the manfanufacturer's reconmendations is that your fluid is "lifetime" and doesn't need changing.

But albeit again, some filters are easily servicable.

 

[cprcubed]

My 2008 Toyota Avalon has the "lifetime" trans fluid "feature". At 300k miles, I decided to change the fluid and filter (mainly just out of curiosity and to learn how to check the fluid level via OBD temperature values). In my opinion the material level in the pan and filter were not bad at all.

Since the BS doesn't have a pan and you have to remove the trans and split the case to change the filter, I'll never change the filter. I'll just do a fluid change/flush. If the filter somehow clogged with debris, the trans probably will have enough issues where more extensive work will be required (JMO). Cheers!

 

[FB71]

Per Ford workshop manual; Transmission fluid filter is not a maintenance item. It is only to be replaced during an overhaul.

The filter is buried under the drive chain and sprockets, and requires a complete disassembly of the transmission. It's purpose is to catch large debris, in the event of a significant failure, to protect the pump and valve body.

If you are finding any particle larger than dust in the fluid, you have major issues, and the trans should be overhauled. Most trans filters have very large orifices in the filter media, and are only designed to catch large particles. Trans oil does not have the surfactant additives to keep particles in suspension, like engine oil. Engine oil filters are designed to capture particles in suspension. Trans oil is expected to drop the particles to the bottom of the pan/housing.

Drain and fill of the trans is an acceptable procedure, at more frequent intervals than specified. This refreshes the fluid additives and some of the base oil.

 

[Mark S.]

...surfactant additives...

Whoa! That sounds like a term someone who knows what they're talking about would use. Care to share your background?

 

[FB71]

Whoa! That sounds like a term someone who knows what they're talking about would use. Care to share your background?

Professor of Automotive Technology, former dealer tech and OE service trainer.

 

[rocks]

Professor of Automotive Technology, former dealer tech and OE service trainer.

Looking forward to reading more of your posts.

 

[Bucko]

Per Ford workshop manual; Transmission fluid filter is not a maintenance item. It is only to be replaced during an overhaul.

The filter is buried under the drive chain and sprockets, and requires a complete disassembly of the transmission. It's purpose is to catch large debris, in the event of a significant failure, to protect the pump and valve body.

If you are finding any particle larger than dust in the fluid, you have major issues, and the trans should be overhauled. Most trans filters have very large orifices in the filter media, and are only designed to catch large particles. Trans oil does not have the surfactant additives to keep particles in suspension, like engine oil. Engine oil filters are designed to capture particles in suspension. Trans oil is expected to drop the particles to the bottom of the pan/housing.

Drain and fill of the trans is an acceptable procedure, at more frequent intervals than specified. This refreshes the fluid additives and some of the base oil.

Impressive information on our BS. I always wondered why some manufacturers stated "lifetime" fluids. I always interpreted that as "when the transmission or its oil fails, that's its lifetime".

Good to know, and thanks for clearing that up.

So, are you saying there is no need to perform periodic fluid changes in these BS transmissions until which time it fails and need rebuilding?

 

[Mark S.]

Looking forward to reading more of your posts.

Me too!

 

[BravoAlpha]

Per Ford workshop manual; Transmission fluid filter is not a maintenance item. It is only to be replaced during an overhaul.

The filter is buried under the drive chain and sprockets, and requires a complete disassembly of the transmission. It's purpose is to catch large debris, in the event of a significant failure, to protect the pump and valve body.

If you are finding any particle larger than dust in the fluid, you have major issues, and the trans should be overhauled. Most trans filters have very large orifices in the filter media, and are only designed to catch large particles. Trans oil does not have the surfactant additives to keep particles in suspension, like engine oil. Engine oil filters are designed to capture particles in suspension. Trans oil is expected to drop the particles to the bottom of the pan/housing.

Drain and fill of the trans is an acceptable procedure, at more frequent intervals than specified. This refreshes the fluid additives and some of the base oil.

good info. thank you

 

[FB71]

So, are you saying there is no need to perform periodic fluid changes in these BS transmissions until which time it fails and need rebuilding?

Honestly, I've noticed the 8F35 seems to be sensitive to fluid quality. Fluid changes more frequent than specified certainly will not hurt. Filter replacement should only be considered during an overhaul.

 

[Jake10080Guy]

Honestly, I've noticed the 8F35 seems to be sensitive to fluid quality. Fluid changes more frequent than specified certainly will not hurt. Filter replacement should only be considered during an overhaul.

It's the same way with the 6F35. People say with 6F units, their ATF showed very black at the first 30,000 miles.

Now I mean for the 8F.. could this be because it basically shares DNA from the 6F? They have identical gear ratios. Etc

 

[Mark S.]

Now I mean for the 8F.. could this be because it basically shares DNA from the 6F?

The 8F transmission is the result of a joint R&D effort between Ford and GM. The version GM uses is a 9-spd; Ford felt the ratio between two of the gears was too short, so it deleted one.

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