Metal in the trans fluid

Joined
Apr 29, 2022
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So I had a oopsie reassembling and installing a trans I rebuilt. Long story short, I reused the converter solenoid and it was faulty and so the converter was locked on permanently.

I was slow to realise what was going on and thought it was an engine problem long enough to take it for a test drive pushing the engine past the bogging down and stalling…. Whoops.

So when I dropped the fluid to replace the solenoid, there was predictably a nice metallic sheen to the fluid! The poor converter lockup clutch got an absolute beating from that test drive!!!! Was a good layer of black gunk on the magnet too, and there was a sediment that had an ever so slightly gritty feel. I assume this is steel from the lockup clutch steel side, so the magnets should catch most of it.

But new solenoid in and it drives wonderfully and the lockup works perfectly. Lockup isn’t slipping as that would throw a fault code so I might be lucky….

Obviously it’s going to get as many oil changes on the trot as required to stop it coming out with metal in it, and I’ll be relying on the new filter and the magnets.

So what’s people’s thoughts on how badly I screwed up? Is it going to live or did I irrevocably condemn it to an early death?
 
You might get lucky, and it lives a long life. Tough to tell w/o an actual inspection, and you didn't mention the unit in question. So speaking in broad terms, I'd probably do a line off fluid exchange, run it a few hundred miles and drop the pan, have a look and swap out the filter just to be sure.
 
It’s a Renault DPO. Made by Seimans and essentially a VW design. Very basic 4 speed front drive unit.

Can’t do a line flush, it runs a coolant heat exchanger so no lines to tap into. And can’t change filter as it’s internal and not accessible without removing and dismantling the trans ;)

So just dropping fluid a few times is all I’ve got! Not worried about the filter, they don’t do much on autos anyways, they’re more of a strainer than a filter..

Nothing to lose though I guess. It’s either stuffed or it isn’t - may as well run it and see. I figure if it lasts the first 1000kms, it’s probably going to be fine long term.
 
Still kicking myself for thinking it was an engine issue and trying to drive it… Seemed obvious at the time…

Lockup solenoid failures are ridiculously rare in European cars, it’s not a GM ;) Pressure regulation solenoid failures are however very common on these - and they’re identical and interchangeable! No idea why it’s always the pressure one that fails, guess it’s in constant operation and the lockup isn’t.

But in the rebuild I removed them both when I stripped and cleaned the valve body. Must have swapped positions on reassembly and the pressure solenoid that in hindsight probably killed the clutch pack that was fried was put into the lockup position.
 
The damage is already done as seen by the metal shavings in such a short period of time. Repeated fluid and filter changes will help prolong the transmission's life but I do not expect a long life out of your transmission.
 
The damage is already done as seen by the metal shavings in such a short period of time. Repeated fluid and filter changes will help prolong the transmission's life but I do not expect a long life out of your transmission.
Well… The metal will be from the steel side of the lockup clutch in the converter. And if it’s locking up nicely still it may yet go for a while as that doesn’t really wear as such in normal use.

So yeah, it’s a matter of whether the contamination in the fluid screws up the rest of it.
 
No shavings and no chunks I should add - just particles from the lockup clutch being horribly abused.
 
Well… The metal will be from the steel side of the lockup clutch in the converter. And if it’s locking up nicely still it may yet go for a while as that doesn’t really wear as such in normal use.

So yeah, it’s a matter of whether the contamination in the fluid screws up the rest of it.
Wouldn't you think if its from the steel side, that the clutch side wouldn't if not be more affected? Yes it may go for a while but its life has been shortened.
 
Wouldn't you think if its from the steel side, that the clutch side wouldn't if not be more affected?
I would have thought so too. But it still works, so I guess there is still friction material.
 
Anyway. Drive it until it drops. Little point in pulling it out and apart now while it’s driving perfectly.

Bloody annoying and disappointing, but they’re a very cheap and easy trans to rebuild at least. Just will involve a fair bit of work I’d rather not do over!
 
Was the trans cooler and lines flushed before the new trans was installed? Could have been residual junk from prior failure.
 
Was the trans cooler and lines flushed before the new trans was installed? Could have been residual junk from prior failure.
It doesn’t have an external cooler, it has a heat exchanger on the trans. It was clean.

No, I was super OCD and it was a spotlessly clean build. I just did horrible horrible things to the converter clutch - and I’m assuming it was the converter clutch slipping, I can’t imagine it would grip and make any other clutch pack slip.

I think if it’s going to fail it will do so fairly quickly. So it’s getting a fluid change (3.5 litres out of the total 6.5 litres capacity) after the first successful drive, and another in a couple of days driving. Then I’ll put another 1000kms on it and see if it’s still good. If the fluid is still free of a metallic sheen then I’ll just send it and see how long it goes for!!
 
That just sucks but really several flushes is all you can do. I’ve never seen a trans survive a failing converter to include metallic fluid. I’m surprised there isn’t hanging sticky valves in the valve body…if it has one. Good luck.
 
That just sucks but really several flushes is all you can do. I’ve never seen a trans survive a failing converter to include metallic fluid. I’m surprised there isn’t hanging sticky valves in the valve body…if it has one. Good luck.
Cheers. If only I’d joined the dots sooner on why it was stumbling in drive. Sigh :(

Yeah there is a conventional valve body with sliding pistons. There is a fine filter in the valve body and another little magnet, there is a big magnet on the filter housing and two more on the front cover over the valve body. They’re all going to be full, but that’s fine if they have caught enough of it.

But no, it’s not looking good. I’m just hoping the metal is a once off addition to the fluid and won’t be ongoing contribution - so if I can get most of it out the rest of the trans (and most importantly the shaft bushes) will not have copped too much of a hit…
 
Well… The metal will be from the steel side of the lockup clutch in the converter. And if it’s locking up nicely still it may yet go for a while as that doesn’t really wear as such in normal use.

So yeah, it’s a matter of whether the contamination in the fluid screws up the rest of it.
It’s locking up under some condition, tbd if it will stay locked up under higher torque/load conditions.

If the fluid is that dirty, the filter is getting clogged with junk. Only time will tell if it will affect performance. My gut says at minimum figure how to put an inline filter (which I think you can’t), or else do a filter replacement, despite the pain of it. Maybe after one or two oil changes so the particles get scavenged and loaded into the filter/drained out.

Good luck!
 
It’s a Renault DPO. Made by Seimans and essentially a VW design. Very basic 4 speed front drive unit.

Can’t do a line flush, it runs a coolant heat exchanger so no lines to tap into. And can’t change filter as it’s internal and not accessible without removing and dismantling the trans ;)

So just dropping fluid a few times is all I’ve got! Not worried about the filter, they don’t do much on autos anyways, they’re more of a strainer than a filter..

Nothing to lose though I guess. It’s either stuffed or it isn’t - may as well run it and see. I figure if it lasts the first 1000kms, it’s probably going to be fine long term.
That changes things quite a bit now that you stated the unit. I would worry about the filter it could very well be plugged up, or plugging up. Good luck.
 
That changes things quite a bit now that you stated the unit. I would worry about the filter it could very well be plugged up, or plugging up. Good luck.
It’s not that much material, I’m not worried about the filter being plugged. Besides, the size of the particles that gives the fluid a sheen are not caught by the filter anyway - trans filters are not like an engine oil filter, they’re jsut a glorified strainer.
 
It’s locking up under some condition, tbd if it will stay locked up under higher torque/load conditions.

If the fluid is that dirty, the filter is getting clogged with junk. Only time will tell if it will affect performance. My gut says at minimum figure how to put an inline filter (which I think you can’t), or else do a filter replacement, despite the pain of it. Maybe after one or two oil changes so the particles get scavenged and loaded into the filter/drained out.

Good luck!
It was only locked because I reused a faulty control solenoid, it’s working perfectly now with a new one installed. Drives really really well!

The amount of sheen is such when the fluid is draining it looks perfect, it’s only when I get a couple of litres in the pan and get the light on the right angle that I can see the ultra fine particles in it.
 
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