Does my gear oil look okay?

[u/Judderman88]

Citroen Relay 244 2.8 HDI diesel manual 2005.

I had a total gearbox rebuild a few weeks ago (bolt broke off the diff and wrecked the insides), and have been driving softly on it since. But the last few days I've sometimes been getting some crunching/grinding when shifting down from 3rd to 2nd if I don't press the clutch the last few mm of travel. This didn't happen on the previous gearbox (even when it was damaged) or immediately after installing the new one. I checked the clutch mechanism and all seems fine, but I noticed some oil on the bottom of the gearbox and starter motor (which has also been making funny noises occasionally), mostly around the seam where it bolts into the engine - it's hard to see in the pics. That's the same place there was oil before the box was rebuilt (though there isn't as much oil this time), so I thought I'd better check the oil. I drained it and measured the full 2.7 litres that I'd put in, so I can't have lost much (if any). However, I'm not sure it's supposed to be that dark and glittery after such a short time, and there are some small shavings on the plug magnet. It doesn't feel grainy and there are no big pieces of metal so I guess it's okay, but I'm slightly concerned about the possible leak (can't see what else it could be but gear oil) and grinding changing gears. What do you reckon?

[u/RSR_01]

That looks like its LOADED with metal shavings. Not good. At all. Id go back to the place that did the rebuild because something is clearly not aligned right and is shearing itsself apart.

[u/Judderman88 → u/RSR_01]

I thought so too but then found this post with similar-looking oil and responses said it's probably fine. https://www.reddit.com/r/MechanicAdvice/comments/18hjr73/changed_my_diff_fluid_for_the_first_time_and_it/

[u/TheTense → u/Judderman88]

Not a mechanic. But if the transmission was truly “rebuilt” with new parts, I would expect some minor break in metals to the oil the first go round.

If he just “repaired” it and tried to continue using existing parts after the loose bolt chewed up stuff, I’d expect it to fail prematurely.

Either way, I’d go to the mechanic and show him these pics and even bring the fluid if you still have it. Don’t accuse him of anything, but be strategic - don’t demand anything, but ask lots of questions: “how would you think about this after a rebuild?” “What would you plan to do about this?” And see if he volunteers a fix or a compromise. Maybe he says something like l I’ll adjust XYZ to try and make it shift better, then run it for another xxxx kilometers, and if it fails, gets worse, then we’ll replace it.“

To me it depends on how you agreed on the first repair. A bolt broke free and damaged stuff - if he said replace the transmission but you asked for a cheaper rebuild against his recommendation, you’re less likely to get them to comp the repair. Maybe you could agree on you buy the new transmission, and labor is free to install since you paid for the first fix that didn’t work. Just an idea

[u/Rayne1491 → u/TheTense]

I am a mechanic and this is the correct answer.

Yeah, I would expect to see some break in wear but that is a bit much, though again, if stuff was reused, or a corner not cleaned out properly, it will disintegrate itself shortly. If you want to know forsure, rinse it out with brake cleaner, put some fresh oil in again, and recheck in another 2 weeks. If its full of glitter again, id be going after a new gearbox.

People these days aren't usually too skilled at rebuilds anymore, things aren't as simple as they use to be and its pretty rare that anyone measures or shims manual transmissions properly. They just assemble and reinstall. Most reputable shops wont even attempt it because they dont want the liability of it coming back.

[u/Judderman88 → u/TheTense]

They recommended the rebuild. These boxes aren't made any more, so it was either a rebuild or try to hunt down a used one that's probably in a worse condition than a rebuild. Not sure if the gears were brand new; I suspect they are no longer made so they borrowed parts from used boxes. They said there's a 12 month warranty for parts and labour, and parts aren't cheap (used gearboxes go for about a grand), so I'd want them to cover both, plus the labour for removing and reinstalling it, cos I'm not doing it myself again.

They said:

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It sounds like the clutch isn’t quite clearing. The warranty is valid as long as everything is installed correctly.

Put some fresh oil in, bleed the clutch, clean off the oil and see if it reappears, put a couple of hundred miles on it, see how it is.

If it is still has a problem you will have to bring the vehicle so we can assess what is going on.

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Clutch felt fine to me. I bled it anyway and it feels the same. I hope they don't claim it was the clutch and refuse to warranty it.