[terios]

Thanks for your answer.

Indeed, this is unusual but unfortunately it happens to my differential.

The drive shaft is well plugged in the gear. But this was not the case two years before and that's what caused the oil leak resulting in an excessive wear of the differential and the drive end (pictures will follow later)

In fact, I've already bought an used transmission with damaged clutch case. I intend to swap it with my clutch case, so I'll end with a combined transmission assembly (my clutch case+used transmission)

My question are:

Is it possible to just remove the clutch case from the transmission without disassembling the input and output shafts?

Or, it is mandatory to disassemble all starting from left (cover and 5th gear) till the differential?

Here is where I am now with two transmissions:

Existing transmission: damaged differential
Used transmission: damaged clutch case

NB. Let's say a transmission assembly is composed of three parts: clutch case + transmission case + cover (left)