Technical Third gear jumps out (1.8 16V)

[SchumacherM]

Hi guys, I need advice. I was recently towing a mate and went full idiot by massively crunching third gear. I just didn't push it in all the way for whatever reason. And so a couple of days ago, I exited a roundabout, slight hill, put it in third, released clutch, and by giving it some power it jumps out.

I kinda know that there isn't much else that can be done but to take the gearbox off and either recondition whatever has broken or get a used box.

But as far as I can research the 1.8 doesn't share its gearbox with other Fiats, which seems impossible to me. Is this true?

And also in case I recon the box, what needs to be replaced?

 

[corcai]

The box wouldn't be exactly the same on other models.

I had a look at eper and the bellhousing is used in alfa 147, 156, GT.

You'd have to open it up to see what needs replacing the good thing is the gears and syncros are probably used in tons of models.
e.g.

Gear part number: 46767059 is used in:

FIAT - PK BARCHETTA (1995-2004)
FIAT - 1M BRAVA G.98 BZ/DS (1998-2001)
FIAT - 1L BRAVO G.98 BZ/DS (1998-2001)
FIAT - PX COUPE' GAMMA'96 (1996-2000)
FIAT - 0D GRANDE PUNTO INTERN. INDIA FL2014 (2014-....)
FIAT - 3M LINEA (2007-....)
FIAT - 0C LINEA INDIA FL2014 (2014-....)
FIAT - 1Q MAREA BZ GAMMA'99 (1999-2002)
FIAT - 1F MULTIPLA (1998-2010)
FIAT - 1X PALIO 2V EXTRA EUROPA (1997-2002)
FIAT - 2H PALIO 2V EXTRA EUROPA REST. 2002 (2002-2011)
FIAT - 3D PALIO 2V REST.2 (2005-2011)
FIAT - 2G PALIO WE EUROPA REST. (2002-2004)
FIAT - 1Y PALIO WE EXTRA EUROPA (1997-2002)
FIAT - 2K PALIO WE EXTRA EUROPA REST. 2002 (2002-2008)
FIAT - 1N PUNTO BZ (1999-2003)
FIAT - 1P PUNTO DS (1999-2003)
FIAT - 2U PUNTO FL.'03 (2003-2010)
FIAT - 2A SIENA EXTRA EUROPA (1997-2002)
FIAT - 2L SIENA EXTRA EUROPA REST.(2002-2012)
FIAT - 3E SIENA REST.2 (2005-2011)
FIAT - 2C STILO BZ/DS (2001-2003)
FIAT - 2V STILO F.L.L. 2003 (2003-2007)
ALFA ROMEO - W3 145 M.Y. '99 (1999-2000)
ALFA ROMEO - W4 146 M.Y. '99 (1999-2000)
ALFA ROMEO - W8 147 BZ/DS (2000-2010)
ALFA ROMEO - T7 156 BENZINA (1997-2002)
ALFA ROMEO - X1 156 M.Y.2002 BZ/DS (2001-2005)
ALFA ROMEO - X2 GT (2003-2010)
ALFA ROMEO - W0 GTV '98 (1998-2005)
ALFA ROMEO - U9 SPIDER '98 (1998-2006)
LANCIA - SX LYBRA BZ (1999-2005)
FIAT PROFESSIONAL - 1W DOBLO (2000-2004)
FIAT PROFESSIONAL - 2W DOBLO MY. 2004 (2004-2005)
FIAT PROFESSIONAL - 1G STRADA (1999-2005)
ABARTH - 85 500 ABARTH MY2012 (2012-....)
ABARTH - 3R NUOVA 500 ABARTH (2008-2012)