Powershift Primary Oil Filter Replacement

[AlanM]

A really poor bit of design: The primary oil filter in the Getrag 6DCT450 (officially) cannot be replaced without removing and completely dismantling the transmission. Even worse, with the valve body cover and the valve body itself removed, you can see and get hold of the filter.

But it can be done. All you need is a bit of determination and a heat gun. The torx screw that retains the filter is where the determination comes in. It's quite tricky to access, you can only move it a fraction of a turn at a time, and it is RIDICULOUS how long it is, given the job it does.

But eventually it'll come out.

Then, to get the old filter out you just remove the magnets, which gives a bit more clearance, and use the heat gun to soften the plastic top half of the filter a bit. Then push it down while levering it out. You have to deform the top half by enough to get the spigot out of the oil pump inlet. It's actually not much, maybe about 10mm.

Getting the new filter in is pretty much the reverse process. A bit of heat (I had the gun set to 150C) to allow the filter top to flex without cracking and a blunt lever, (I used the handle of a small hammer) you push the top of the filter down and in, getting the spigot under the oil pump pick up.

Once it's under you can push it back and forth until the spigot pops up into the pick up. Then a couple of screwdrivers under the filter to push the spigot all the way in.

Now comes the hard part: getting that ridiculously long screw back in. I actually ground the tip of the screw into a bit of a point, since there's no way of seeing when the screw hole in the filter is aligned with the hole in the oil pump pick up. Grinding a point helps it to align itself.

Then it's just another 45 minutes screwing it in a 16th of a turn at a time... it probably wasn't that long but it seemed longer.

So anyway, it can be done, and a lot quicker and less work than removing and splitting the transmission.

[oldgun]

the question is , do you have to replace that main filter which is only for big chunk of particles.

[AlanM]

Originally Posted by oldgun

the question is , do you have to replace that main filter which is only for big chunk of particles.

It's a paper filter, not a strainer, so it would get at least partially blocked by just the material that comes off the clutch plates. The magnets in these boxes get a thick coating of sludge on them, and they certainly wouldn't be as effective once covered like that. So that leaves the other two filters to keep the muck out. But the external one is in line with the oil cooler so only actually works when the oil is hot. All the oil constantly circulates through the internal one so having a clean one in there certainly can't hurt.

These transmissions rely on oil pressure to properly engage the clutches. The internal filter is on the suction side of the oil pump so restrictions here could quite possibly impact on the operation.

[AlCan]

Sounds like a real mission.


Did you happen to take any photos while you had it apart?


I had no idea that filter was paper. I totally agree, really lousy design. No wonder Getrag changed their name. Such a shame, as some parts of the transmission are very smart. But it can't be allowed to last too long, right!?

[AlanM]

The hardest part is getting the screw out and then back in. There's not much access to it.

Actually getting the filter out and in isn't so bad, once you heat it up a bit to get a bit more flex.

The filter element itself is like a bag, with the opening at the intake hole, which effectively doubles the surface area.

Sorry, I didn't take any photos, but there is a YouTube video on a channel called "Life on octane".

[oldgun]

Managed to get the job don, took 3 hours with heat gun.

[AlCan]

Thanks Alan,

This is very helpful, especially the video pointer.

For ref, it's here: https://youtu.be/ULCgqmGZ9tY

Hand held camera which is very busy, but you do get a few glimpses of the paper element inside the plastic and steel filter box. Looks awfully thin!

Originally Posted by AlanM

The filter element itself is like a bag, with the opening at the intake hole, which effectively doubles the surface area.

Sounds very like a disposable vacuum cleaner bag.

I guess this construction explains why the transmission suffers mechatronic faults after 1-200,000km or so of not getting transmission servicing. Still guessing, but my guess is that once that paper bag gets thoroughly clogged and the pressure drop goes up, it tears open...

Hmmm. Is that external filter even in the oil flow path to the control components, or is it just a bypass filter? Maybe that's why the primary, paper bag filter is so much finer than a steel mesh or similar pickup would be.

Like it's designed to punish those who don't pay for regular transmission servicing.

So, many thanks for this post, I'm off to buy a primary trans filter asap!

Anyone have any idea of what the oil pressure is at the pump outlet? Maybe that plastic external filter housing wouldn't be up to it.

[AlCan]

Uhh... Can't edit last post, but I see now that the external filter is connected via low pressure hose and hose clips, so can't be much pressure there. Must be a bypass filter.

[AlCan]

Originally Posted by AlanM

The torx screw that retains the filter is where the determination comes in. It's quite tricky to access, you can only move it a fraction of a turn at a time, and it is RIDICULOUS how long it is, given the job it does.

Found a very interesting video on YouTube. It's from Latvia, and it's in Russian, with a few recognisable English terms thrown in. Even not knowing a word of Russian, it's quite enlightening and I learned a couple of Russian words along the way: Boltik and Plastika - which was the subject of quite a bit of discussion... The guy who does the teardown is obviously very familiar with these boxes, and spotted something abnormal right at the start. Only realised that, by following the transcript once translated into English. (I'll try to post the translation as an attachment in case anyone is interested.)

https://www.youtube.com/watch?v=j4PdTiTZ9y4&t=1000s (Link starts where the sump filter is being discussed.)

I was particularly keen to see if I could figure out how the oil maintains a higher level in the Mechatronics section than in the transmission housing, but it's not at all obvious (to me anyway). The Oil Pump picks up from the Sump Intake Filter in the Mechatronic section (which would tend to drain it), and presumably most of the fluid returns through exhaust ports on the Mechatronic slab (back into the Mech section). But I guess a certain amount goes into the Bell housing, via input shaft / clutch ring seals leakage) which I suppose ultimately connects to the transmission section. It seems to me, there must be a way that it keeps the Mech section topped up. Maybe the crown wheel acts as an oil slinger and "throws it over the wall"? I have no idea. Anyone else?

There are what seem to be pump scrolls cast into the bearing end housings but whether that's what does it via hollow shafts, I don't know.

Anyway, the sump filter and pump feature at about 17:00 into the video, and I see that the bolt that holds the sump filter spigot in place has a dual function, hence its length. It also helps bolt the oil pump into the housing, so I imagine it needs to be tightened back up pretty well.

My replacement sump filter / pickups arrived today, but they are much smaller than they look in all the videos I've seen. Maybe it's just the fact of viewing on a large screen, but mine, although looking the right shape etc, are only 192mm long (overall) x 137mm wide (overall). They are a weird shape - no edge is parallel to its opposite and only one corner is 90°.

AlanM, did you keep your old filter, and did you happen to cut it open, by any chance? I'm very curious about how it's constructed but would like to know before I pull mine out.

BTW, I'm now convinced that all the oil, pressure fed to the mech unit etc must pass through the sump pickup filter, so for bits of plastic to get in and block orifices and jam solenoid valves, there must be a breakdown of the filter element. Found a schematic for the full hydraulic circuit, produced by the ATSG, which I haven't found in the Tech Resources section, but it can be downloaded here:

https://godsskill.files.wordpress.co...rvice-menu.pdf

Enjoy!

[AlanM]

Originally Posted by AlCan

Found a very interesting video on YouTube. It's from Latvia, and it's in Russian, with a few recognisable English terms thrown in. Even not knowing a word of Russian, it's quite enlightening and I learned a couple of Russian words along the way: Boltik and Plastika - which was the subject of quite a bit of discussion... The guy who does the teardown is obviously very familiar with these boxes, and spotted something abnormal right at the start. Only realised that, by following the transcript once translated into English. (I'll try to post the translation as an attachment in case anyone is interested.)

https://www.youtube.com/watch?v=j4PdTiTZ9y4&t=1000s (Link starts where the sump filter is being discussed.)

I was particularly keen to see if I could figure out how the oil maintains a higher level in the Mechatronics section than in the transmission housing, but it's not at all obvious (to me anyway). The Oil Pump picks up from the Sump Intake Filter in the Mechatronic section (which would tend to drain it), and presumably most of the fluid returns through exhaust ports on the Mechatronic slab (back into the Mech section). But I guess a certain amount goes into the Bell housing, via input shaft / clutch ring seals leakage) which I suppose ultimately connects to the transmission section. It seems to me, there must be a way that it keeps the Mech section topped up. Maybe the crown wheel acts as an oil slinger and "throws it over the wall"? I have no idea. Anyone else?

There are what seem to be pump scrolls cast into the bearing end housings but whether that's what does it via hollow shafts, I don't know.

Anyway, the sump filter and pump feature at about 17:00 into the video, and I see that the bolt that holds the sump filter spigot in place has a dual function, hence its length. It also helps bolt the oil pump into the housing, so I imagine it needs to be tightened back up pretty well.

My replacement sump filter / pickups arrived today, but they are much smaller than they look in all the videos I've seen. Maybe it's just the fact of viewing on a large screen, but mine, although looking the right shape etc, are only 192mm long (overall) x 137mm wide (overall). They are a weird shape - no edge is parallel to its opposite and only one corner is 90°.

AlanM, did you keep your old filter, and did you happen to cut it open, by any chance? I'm very curious about how it's constructed but would like to know before I pull mine out.

BTW, I'm now convinced that all the oil, pressure fed to the mech unit etc must pass through the sump pickup filter, so for bits of plastic to get in and block orifices and jam solenoid valves, there must be a breakdown of the filter element. Found a schematic for the full hydraulic circuit, produced by the ATSG, which I haven't found in the Tech Resources section, but it can be downloaded here:

https://godsskill.files.wordpress.co...rvice-menu.pdf

Enjoy!

I don't know how either, but oil must get transferred back from the clutch and gearbox section to the mechatronic section for the plastic bits to get there. And they definitely do, I've seen them.

I didn't keep the old filter, but we did cut it open. It didn't seem to have any holes in it, but this car doesn't have the problems usually associated with the clutch spring retainers breaking up either. It was just heavily contaminated with thick black sludge.

Best of luck with your filter, as long as you're patient and persistent you'll get it done.

[AlanM]

Originally Posted by AlCan

BTW, I'm now convinced that all the oil, pressure fed to the mech unit etc must pass through the sump pickup filter, so for bits of plastic to get in and block orifices and jam solenoid valves, there must be a breakdown of the filter element. Found a schematic for the full hydraulic circuit, produced by the ATSG, which I haven't found in the Tech Resources section, but it can be downloaded here:

https://godsskill.files.wordpress.co...rvice-menu.pdf


Enjoy!

I asked a guy who reconditions these transmissions how the plastic gets past the filter. It's actually pretty simple. When you look at the front of the valve body there's quite a few ports. When the valves are moving they can vent oil out of these ports, but also suck some in. Because the plastic is suspended in the oil, the bits can get sucked right into the valves through these ports.

[AlanM]

Thought I should mention, something I've never seen on a video about working on these valve bodies, is to make sure you clean the solenoid contact pads on the TCM. They can get a varnish like coating on them, which can prevent the solenoids from getting current.

Quite often you'll see a pair of shiny dots on the contact pads, where the solenoid was, but once you disturb them, they may contact in a different spot.