Iron filings on gear magnet plug

[steveq]

I changed the oil in the manual gearbox on my C Class a couple of years ago.
It is slightly different to yours as mine is rear wheel drive.
My car had about 65,000 miles on it (120,000 kms).
The old oil was black and there were metal shavings on the drain plug - maybe not as much as yours but there were some.
There wasn't a problem changing gear before I changed the oil but I did think it was smoother after the oil change.

Someone said to clean the pan - there isn't a sump or a filter, just a drain and fill plug/bolt.

 

[Exp21]

In another forum many report that w169 and w245 gearbox are "stiff" when cold. It seems to be a characteristic. My doubt is how a car like this could survive extreme winter conditions. Below 0° C you can't shift gear for the first miles, I don't even imagine at -20°C

 

[Exp21]

Today I tried gearbox with -2° C. It's still stiff and 2nd gear "scratches" for the first miles. It improved a lot but it's still problematic if compared with other cars. I put inside Febi 21829 oil, with the WIS recommended MB 235.10 specific. It's a 75w GL-4 oil. If anyone has an idea to fix this issue let me please know. Thank you

 

[Exp21]

Hi everyone. I'd like to make an attempt replacing for the 2nd time the gearbox oil, because the first three gears are still stiff and rough. With the new oil I'd like to put also the Liqui moly gear oil additive, to reduce friction.

The Febi oil now inside gearbox has MB 235.10 spec as recommended. But since shifts aren't fluid enough, I'd like to try this oil in picture. It's recommended for my w245 model in Liqui Moly website, but it has not the MB 235.10 spec. Would you trust it anyway or is fundamental to respect the spec recommended by MB? I know it's a technical question, but I'm no expert.

Thank you for help

 

[Botus]

the specific characteristics of auto fluid is a very exact science for the specific application.... lots and lots of time and effort is used creating what's required....

using ANYTHING else is unlikely to help and may well be a disaster... the world of a GM built bulletproof 3 speed that after 20 years of abuse can feel better with a litre of gloop passed us by 35 years ago....

I would not expect a Merc box to improve by meddling with addatives.... I'm open to those brave enough to wreck it, to counter with real advice of gearbox model, age, mileage, life history and exactly what it had in it and what they added to share their experience...

on modern boxes with so much designed to give up electronics and with so much wear and tear taking place, the issues mostly lie in faulty control solenoids, that may just have their gauze filter blocked with metal debris and or with O rings that have become destroyed by all the trash that's been cycling round.... if that's the case then gloop is probably just a cost that would be better spent on a real fix

on a side note of your comment...… once power has got (via the fluid) in and out of the TC, an auto only drives down the road by the "friction" created by a whiff of trans fluid pressure, basically holding together wet multliplate bike clutch packs (...minus any springs) - messing with the friction levels the right oil brings to the party, can lead to tears and or significant wear

 

[Blobcat]

the specific characteristics of auto fluid is a very exact science for the specific application.... lots and lots of time and effort is used creating what's required....

using ANYTHING else is unlikely to help and may well be a disaster... the world of a GM built bulletproof 3 speed that after 20 years of abuse can feel better with a litre of gloop passed us by 35 years ago....

I would not expect a Merc box to improve by meddling with addatives.... I'm open to those brave enough to wreck it, to counter with real advice of gearbox model, age, mileage, life history and exactly what it had in it and what they added to share their experience...

on modern boxes with so much designed to give up electronics and with so much wear and tear taking place, the issues mostly lie in faulty control solenoids, that may just have their gauze filter blocked with metal debris and or with O rings that have become destroyed by all the trash that's been cycling round.... if that's the case then gloop is probably just a cost that would be better spent on a real fix

on a side note of your comment...… once power has got (via the fluid) in and out of the TC, an auto only drives down the road by the "friction" created by a whiff of trans fluid pressure, basically holding together wet multliplate bike clutch packs minus any springs - messing with the friction levels the right oil brings to the party, can lead to tears and or significant wear

The gearbox is a manual in this incidence ( I’d still not be using any additives though)

 

[Botus]

The gearbox is a manual in this incidence ( I’d still not be using any additives though)

oh

 

[Exp21]

Thank you for your reply. I've never believed in additives, my belief is that additives are already in lubricants and I usually replace the oil more frequently rather than using additives. But in this case I have already "overmaintained" the gearbox, since MB doesn't put in schedule the gearbox oil replacement.

I did it because gearbox was no more usable when cold. But now, even with fresh Febi oil, it's not that good. And I've read of miracles about this Liqui Moly additive.

Car has only 90k miles and I would try anything to avoid destroying the gearbox because in city driving I feel it rough.

Honestly I don't know if it's due to clutch wear or if gearbox has already been damaged (when I replaced the oil it was low in level).

Anyway Liqui Moly recommends that product on their website, I don't think it could be so wrong. MB recommends a 75w85 Mobil oil.

 

[Botus]

years back in days gone by, the getrag box in rare Jag manuals circa 1988 - had vastly improved changes by moving to an approved wrong fluid.... for want of a decent recollection - I thought we did put auto trans fluid in them as a factory approved lighten the gear change mod

before going that route I'd check I'm not a mad old fool with a dodgy memory

 

[Botus]

if you park any manual with the engine off.... (for good measure on the flat, handbrake off) when the engine, gearbox and rest of the drive train are unloaded and in a happy place, the shift in and out gear can be as light as though a working clutch is fully down. If you get the car in this situation and the shift is still horrible, then the issue maybe the linkage and or the box.... if it only gets stiff and nasty when its running, then it can be the clutch that's not right.... the clutch plate can get stuck or tight on the input shaft and know matter if the actuation has the full travel, the change can be horribly stiff

 

[Exp21]

thanks

I think that clutch is responsible only for a 15%-20% at the most. In fact, after replacing the 10 years old oil, it improved dramatically. But still when cold first miles, first gears are rough and they tend to scratch during shifting. But since when hot improves, clutch is excluded for the most part.

My great fear is that 7 months ago a mechanic replaced my cv joint removing the axle and let some oil leak from the seal not replacing it. And I did 4-5k miles with low oil level destroying gearbox. But I'll never know this. It got worse just after his job so.....only god knows.

 

[LostKiwi]

If the input shaft splines of the gearbox have become contaminated with oil, grease or dirt the clutch plate can stick. As the engine and gearbox warm up the oil/grease/dirt gets less thick allowing the plate to slide more freely on the splines.
Quick test: engine off push clutch down and engage each gear sequentially. If it's smooth start engine. If it's now difficult the clutch is the problem.
Also when trying to engage gears when stationary can you hear a noise as you push the gearstick? If so the clutch is dragging and the noise is the synchromesh trying to stop the input shaft to allow engagement.
Does it also do it in reverse?

 

[Exp21]

Thank you very much
I made a video last day when engaging 1st and 2nd gears with engine off, watching the leverages and mechanism. It's a little rough also with engine off and makes some noises (I suppose normal?).

I don't know if it helps but here's the video (it's short don't worry).

20210507_124148_1_1_1.mp4

www.amazon.it

 

[LostKiwi]

Those noises sound normal to me.

 

[Exp21]

To me too. Thanks again. I think that it's a characteristic of that gearbox (in many forums they complain the same). I'll give a try with the additive I think

 

[steveq]

Be careful with the quantity of oil you have in the 'box.
I know that the gearbox in the W204 it is important to only put in 1.5 litres.
This is completely different to changing the oil in the rear differential where it is filled until it starts to flow out the filler hole.

 

[Exp21]

I'm talking about a manual w245. Probably you misunderstood, but thanks anyway

 

[Mr Greedy]

A much older car, but my 2004 w203 6 speed manual on a C320 V6 petrol was just the same when cold.
New gearbox oil made virually no difference.
Further reading suggested that when testing the gearbox during design, it worked fine in a factory (at 20°C), but alas, not when cold and outside. In the summer months it was fine.
I think it was an oil pressure relief channel to do with the 1st and 2nd gears. 1st was particularly bad when cold if moving at all. When all up to temperature it was fine.
There was an upgraded part issued for the gearbox that resolved the issue, but that would require a gearbox strip down to install, so not something I ever had done. I enquired about this part at my local Mercedes dealer, and they were surprised that the system showed they had sold hundreds of this part in the past year, and therefore concluded this was a common issue.

Thankfully with the torquey V6, I could get round this problem by setting off in 2nd gear if facing slightly downhill and by being gentle on the clutch, or if uphill, go from 1st up to e.g. 3-4k rpm, then change straight to 3rd. A bit of a pain, but not as painful as £1500 on a gearbox strip down and new clutch.

It sounds like a very similar issue, although I'm sure the gearboxes will be significantly different.

 

[Exp21]

Thank you. Yes, they are similar symptoms. I've read many similar complaints about w169 and w245 gearboxes. It's a pity because it's a really big weak point. For a thing like that one could change car. If an additive could improve it just that 20% to make it a little more fluid I'd be happy enough.

Anyway I can't imagine a cold start at say - 20°C. Probably I'd have to do the first 5 miles in first gear. 2nd wouldn't go in at all.

 

[Botus]

If the input shaft splines of the gearbox have become contaminated with oil, grease or dirt the clutch plate can stick. As the engine and gearbox warm up the oil/grease/dirt gets less thick allowing the plate to slide more freely on the splines.
Quick test: engine off push clutch down and engage each gear sequentially. If it's smooth start engine. If it's now difficult the clutch is the problem.
Also when trying to engage gears when stationary can you hear a noise as you push the gearstick? If so the clutch is dragging and the noise is the synchromesh trying to stop the input shaft to allow engagement.
Does it also do it in reverse?

this is what I'd said two posts above yours... rust is the biggy, as it doesn't improve and the box just has to come out