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Yesterday I was unfortunate enough to have my clutch give up while a few miles away from home. My clutch pedal started vibration a lot and then after a quick pop, I had no gears. I didn't know you could turn the engine off and select gear and then turn it back on in gear, as it was a first occurrence like that for me. I pushed the clutch in and with some extra force tried all gears, sometimes pumping the clutch, sometimes just holding it fully pressed on the pedal until I finally managed to get into 2nd gear. I didn't put crazy amount of weight on the gear lever but it definitely had some force to it. Once I turned the engine off, I tried all gears with no clutch pedal pressed and they all go in pretty smooth, 5th and 6th gear slightly harder than 1 trough 4 and reverse, but still go in and the gearstick doesn't pop out.

Could I have damaged something internal in the box itself by those forcible attempts to get into gear? 5th and 6th gear being a bit harder to engage with engine turned off makes me worry or is it normal for them to get in slightly harder than 1st and reverse for example? Anything I can try to check it? My mechanic will take the car next week as he's on holiday and I'm worried somewhat, but he said some bearing (throw-out?, input shaft?) went out most likely. What do you think?

The car is a diesel with a DMF, Alfa 147 C630 6-speed gearbox.

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Yes, you can damage your transmission by "forcing" the shifter. The most common damage would be bent or broken shift forks. These are fork-shaped parts that move the gears along the shafts to engage with other gears. When you force the lever you put excess stress on the forks and they can bend or break.

You will know they are damaged because the transmission will not longer shift at all into certain gears or will be difficult to shift.

Unfortunately, repairing this usually means removing and disassembling the transmission.

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  • Well if the gears go in relatively smoothly with engine off, does that mean the damage hasn't occurred yet? I read somewhere that it's normal some gears to be harder to engage with engine off due to synchros not working, which is what I hope is my issue with 5th and 6th. I noticed it was slightly harder the first time around but then once I managed to get into the gear once, it was rather smooth afterwards. Don't know what that tells us.
    – Tisho
    Jul 26 at 15:05
  • I'm not sure that "static" shift tests are going to be representative of in-service problems.
    – jwh20
    Jul 26 at 15:14
  • I see, well the car can't go anywhere now so I can't test it. What worries me - I'd have to have the gearbox out to replace whatever caused the issue and since the gearbox internals aren't in the bell housing, I'd have to get it all installed back and then check if it needs to come down again for a new fork? Is there a possible way to actually test the condition before installing the new clutch/bearing or whatever is needed?
    – Tisho
    Jul 26 at 15:20
  • I don't know of any way to tell for sure other than to open up the transmission and inspect the shift forks. My guess, however, is that unless you applied considerable excess force in shifting, that the forks are not bent.
    – jwh20
    Jul 26 at 15:47
  • Don't know if it makes a difference, but I didn't actually manage to get into gear. I was basically hitting a stop as if the clutch pedal wasn't pressed. Once it got to that point, I tried to force it further without success. Wasn't crazy yanking, but still some force was applied. The gears didn't grind, they just hit the bump where they couldn't get into gear.
    – Tisho
    Jul 26 at 16:02
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Manual xmissions are reliable and way ahead of automatics since the beginning of motorized vehicles. It would be extremely difficult to damage manual xmission gears by force no matter how strong a person is as the xmission gears will literally talk to you, screaming as gears grind. You probably wore out either the clutch disc or blew the hydraulic system that makes clutches engage/disengage with pedal pushing/releasing. The hydraulic system is acts the same way as hydraulic brakes.

The fact that you can shift gears without depressing the clutch pedal is the accepted test to separate a xmission gearbox issue and shift assembly from most likely a blown clutch master or slave cylinder or worn out clutch disc. This is typical of long term use of manual xmissions with hydraulics and clutch discs wearing out in normal driving. If the clutch hydraulics are blown hydraulic oil should be leaking and leave a tell tale puddle on the ground. Brake fluid is used in clutch hydraulics.

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  • Thank you for the feedback. Just by symptoms I was told a clutch bearing had failed. No grinding of gears was heard. It gives me hope you saying they are resilient as I’m worrying a ton I might’ve bent the fork selectors. Car goes into any gear no issues with engine off, albeit 5th and 6th seemed harder than the rest. Can this be normal deemed normal due to synchros or something? I’m not a super strong person and I didn’t put crazy amount of pressure on the shifter, but it definitely had some force to it. In moments of panic, we don’t make the smartest choices plus I didn’t know any better.
    – Tisho
    Jul 27 at 6:10
  • Having rebuilt manual transmissions and replaced the synchro rings and bearings as well as some of the gears then I do not agree that they cannot be damaged.
    – Solar Mike
    Jul 27 at 9:21
  • Solar Mike, your experience of manual xmissio gear boxes doesn't explain how they became damaged. The fact that the OP can shift into gears with engine off most likely suggests damage outside the gear box.
    – F Dryer
    Jul 27 at 22:26
  • A trusted mechanic would be the kind to make an initial guess such as throwout bearing while others may suggest a xmission teardown. One would offer a low cost guess while the other would capitalize on unfamiliarity of manual xmission failures. I searched for your vehicle and viewed one video repair to linkages, sticking as the gear shift lever wasn't moving normally. Expertise in a specific vehicle are either at dealer or repair shops more familiar with a specific model.
    – F Dryer
    Jul 27 at 22:52
  • Yes, a very common issue on my car is some top hat bushes on the end of the linkages, which cause the shifter to stiffen, have a harder time getting in gear and returning to neutral position. I have decided to get it done while gearbox is out and generally change the oil and all perished bushings as preventative maintenance. I’d like to have the gearbox removal labour only once on my bills thus fixing most items, even those not in immediate need.
    – Tisho
    Jul 28 at 11:48

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