Koks18

Hi there,

I've had this problem ever since I bought it a couple of months ago. It's a 2009 C class.

Basically, once I shift to 5th after aprox. 10 kms I feel and hear grinding in the gearbox. It even happens idle if I rev the engine up. I went to a mechanic and he said it's a syncro so I went for it and replaced it, however that did nothing at all. This happens on 5th gear only, no matter if I shift up or down.

Now, the mechanic also said the clutch needs replacing but I highly doubt that is the issue.

Any ideas? This drives me insane.

Thanks in advance.

Moto_Guzzi

You said in 5th gear, then you said when it idle and you ref it you hear the grind, do you rev it from neutral, or do you ref it standing still with 5th gear selected and the clutch pressed in-?

All your gear linkage bushings still present and minimum play-?

If you put it in 1st, and press the clutch down, does it want to drag on-?

The clutch normally has a release bearing.

While you had the gearbox open, was all the splines and groves in gears ok, not stripped somewhat, all bearings ok-, casing not cracked-?

I will raise the rear wheels, turn it in different gears clutch in clutch out and listen for sounds.....

Koks18

It happens if I rev it a couple of times in neutral and then try shifting to 5th while idle.

The mechanic had nothing else to mention beside that the flywheel & clutch are in a bad shape and that I am going to need to replace them soon. Also, when I called back he said there is nothing else that could cause the issue but the gear fork and mentioned that it's not worth replacing - "shift slowly and nothing can happen." 🙄

It's just sad that I paid good money for the job, however nothing changed - new syncro & tooth wheel for the 5th gear.

Everything seems normal beside the mentioned grind in 5th and jolts here and there between shifting gears and that is due to the clutch itself, imo.

Koks18

Update: did a little bit of testing and it grinds EVERY time I rev the engine to about 3000 RPM while idling.

Moto_Guzzi

Maybe you have more than one problem in series, like:

1-The clutch as have been said & bearing to do with clutch.
2-The 5th gear if it is the 5th gear wants to engage but should not.
5-Gearbox oil type in gearbox.