MK4 TDCI rattle

[PeterT71]

Hello all, my Mondeo has a anoying rattle that only occurs under certain situations? It generally occurs when stopped at lights or on an incline when the car is still in drive - underload and my foot is on the brake. From inside the car it sounds reasonably loud. Has anyone experienced this same problem and can possibly suggest some potential ideas?
I thought it may have been the engine mounts so I've replaced the top two mounts and obviously it wasn't those.
The car has 183000kms and despite my best efforts to prolong its lifespan through regular maintenance its starting to get a bit 'tired' and clunky. Great car, just don't know whether its going to become a future money pit.

[AlCan]

Could be many things... Lower (rear) engine mount? Exhaust system? Muffler? Trim... Not really enough information. What year is it? When you say "underload", what do you mean? If foot on brake, I'd expect No Load.

Anyway, my suggestion is try to find a safe spot, like your driveway, where you can set up the car to make the rattle, then get someone else to wander about the car trying to pinpoint the general direction of the sound, and go from there. Of course, keep your foot on the brake pedal! Or swap places...

I'm presuming it's a PowerShift, so letting your foot off the brake will cause the clutch to start engaging. You don't want to prolong that, not to mention being potentially dangerous.

All cars end up becoming money pits if you wait long enough... If it is a Powershift, read up here about changing the Primary Transmission Filter, if you want to keep it past 200,000-odd km.

[PeterT71]

Originally Posted by AlCan

Could be many things... Lower (rear) engine mount? Exhaust system? Muffler? Trim... Not really enough information. What year is it? When you say "underload", what do you mean? If foot on brake, I'd expect No Load.

Anyway, my suggestion is try to find a safe spot, like your driveway, where you can set up the car to make the rattle, then get someone else to wander about the car trying to pinpoint the general direction of the sound, and go from there. Of course, keep your foot on the brake pedal! Or swap places...

I'm presuming it's a PowerShift, so letting your foot off the brake will cause the clutch to start engaging. You don't want to prolong that, not to mention being potentially dangerous.

All cars end up becoming money pits if you wait long enough... If it is a Powershift, read up here about changing the Primary Transmission Filter, if you want to keep it past 200,000-odd km.

Thanks Alcan for replying. The noise is consistant with an exhaust system rattle. It's 2011 2.0 TDCI with a Powershift. I changed the trans fluid and filter 20,000 km ago so it's due in another 40,000km.

When I meant underload, I just mean't stationary and in drive. The noise stops if I shift into neutral. I'm hoping its nothing to do with the transmission as the car will practically be a write off it it needs a new one. It does still shift relatively smoothly but I have noticed some occasional minor 'clunking' when it downshifts at low speed.

I will certainly read up on changing the Primary Transmission filter. Thanks again.

[AlCan]

Could the "clunking" be described as a rattle, a chatter or a clatter a bit like a graunch? I have one that makes sounds like that slightly after, I'd say, a gear change in the lower gears. I believe it's (multi-)clutch-plate rattle as it releases the previous gear, and I'm not worrying about it. Just a sign it's getting older, but a way to go yet.

As I see it, mechanically, these transmissions (gears, bearings etc) are pretty robust.

The two major weaknesses are (1) in the clutches - the plastic slider bits that simply disintegrate and then allow the clutch damper springs to rub against and wear the outer faces of the pressed clutch housing "tunnel" they live inside. This creates excess (steel) wear metal which leads to (2) the second weakness.

The wear metal covers the magnets until they lose effectiveness, at which point, more of it begins to float about in the oil/DCT Fluid until it gets trapped in the primary Trans Fluid filter. It builds up there until the filter gets clogged, and at some point usually around 200,000km, the filter (typically?) bursts a seam. This allows dirt into the mechatronics, and typically brings on a sudden transmission "failure". "Transmission limited function", limp mode and only a few gears (maybe). Or no "gears" at all.

Replace the ruptured primary filter and clean out the mech unit (valve body etc), give it some clean fluid and you're likely to get a good distance more out if it.

But I believe in proactive maintenance, so try to change that filter before it fails.

[PeterT71]

Thanks heaps AlCan for replying.

I have looked at all the info related to replacing the primary filter and are concerned that I may stuff it up. The process of heating the filter is what mainly worries me.
I have noticed a slight whirring/rattling noise when the auto shifts from 1st to second gear? This noise is unrealted to the chatter/rattle noise I started in this thread.

I'm also all for doing as much proactive maintenance as possible to extend the vehicles lifespan. I was thinking about halving the recommended DCT450 service intervals to 30,000km instead of 60,000km. 4 litres of Penrite DCT fluid is only $105 from Supercheap. The filters are only $13 from Aliexpress.

Geeze I wish Getrag had of made it simpler to replace the primary filter.

[AlCan]

Hi PeterT71,

I can't explain the whirring/rattling noise, but when it engages 2nd gear, the even-gear clutch plates will start spinning. I don't know what the plates do when their 3 gears are in Neutral, but I guess they free wheel, maybe slowly. So the noise could be related to the even-gear clutch.

Do you experience clutch shuddering at all? I'm not yet too sure about what causes that, but I imagine disintegrated plastic damper spring spacer-sliders would have a lot to do with it. My old 2011 Powershift has bad clutch shudder, but can't say I've noticed whirring. And it still goes, you just have to know how to drive it. Hillstarts or attempting rapid takeoffs are the biggest issue, but both seem to be improved with a left foot on the brakes as you start off.

Anyway, the job of changing that primary filter is not really as scary as it sounds. I found it very nerve-wracking the first time too. But it is a bit of a performance, as (as far as I know), you have to take the mechatronic unit out as well. I had to take mine out anyway, so didn't even look at whether the filter could be changed with it in place, but I'd doubt it. It would be very difficult, I'm sure.

I can write up the process as I remember it, if you'd like.

Have you seen the YouTube video by "Life on Octane" - I think it's linked in the Primary Filter Change thread? Whatever you do, don't try it his way and trim of the top off the filter spigot. You need to be careful to keep any dirt from going into the clean side of the filter, and that way sure isn't it! The main thing is preparation, and getting the top of the filter to soften enough. I overreacted to the comments by the Life on Octane guy about needing lots and lots of heat and used an electric paint stripper gun, but it doesn't need to be that hot. In fact, I melted some of the surface of my filter, but fortunately didn't do any real damage.

Here are a few pointers to start with. Before you start:

1. Remove undertray beneath the engine/trans. 8 x 10mm bolts into plastic captive nuts.
2. Drain the Trans fluid before you start the rest. The longer it has to drain, the less unpleasant the rest of the job will be. I ended up leaving mine overnight, because of when I started.
3. I also removed the front undertray, which has a lot more bolts/screws, but found it worth the trouble, especially for removing the intercooler hose clamp. I thought it was going to help drain the radiator via the trap, but Nah!
4. Prepare to drain the coolant. It seems this can't be avoided. You'll need to move the bottom radiator hose out of the way. I saved my coolant, filtered and reused. If replacing, you need the Red flavour! There is a drain tap on the bottom (side) of the radiator, but it doesn't seem to be drilled through and doesn't work on mine nor others. Shame, as that would make the job much easier. I used the rubber hose that branches off to the Trans Fluid cooler (heat-exchanger) to drain the coolant. Plug off the cooler outlet and drain from the hose with a bit of PVC tubing. 13mm I think, fits inside that hose. Might be 16mm? But before you start on the coolant:
5. Remove the Turbo-to-Intercooler pipe. It's only a couple of clamps and a couple of bolts, but they use locknuts and a long thread, so a standard socket may not do it.
6. After draining the coolant via the heat-exchanger branch (try to get as much out that way as possible by twisting the bottom hose around so the heat-exchanger pipe is as low as possible.
7. Unclip the Bottom Radiator hose from the radiator. The clips slide out sideways. The bottom coupling to the radiator is keyed, so don't try to twist it. If you take the clip right off, then you can more easily jiggle the coupling from left to right to get the seal to unstick. You'll probably find more coolant escaping.
8. About now, it's probably safe - a good time- to unplug the electrical connector from the front of the transmission. It has a round connector with a plastic locking ring with a "handle" on it. Rotate the handle/lug anti-clockwise to release, and the connector should just come straight out.
9. The most important item of preparation. You'll need some string or wire or such like. You need to tie the electrical wiring harness that runs diagonally across the front of the black plastic transmission cover forward as much as possible. You need every millimetre to get the mechatronic unit out as it has long probes that protrude into the transmission.

I have to stop here for now - but this is a start.

[PeterT71]

[QUOTE=AlCan;6959570]Hi PeterT71,

Thanks very much for your advice AlCan. I have printed it off and will certainly keep it for future reference.

I can't say that my Mondeo is experiencing any clutch shudder. Cheers mate.

[PeterT71]

Problem solved. The noise was caused by the rear engine torque mount.