Fiat 131 Gearbox Layshaft and Input Part Number

[njgierszon]

I just pulled apart my 1981 date stamped 131 box to find the input and layshaft badly damaged.

Trying to source some new replacement items but have come across several part numbers on the net. Reading previous threads on the 131 gearbox at some point in 1979 (78 maybe) the ratios and teeth profiles changed.

Casing numbers are:
131 BB 1A 1005
4417996 5A

Part numbers I have found so far are in my research are;

Input shaft:
4346271 (says for 1800 and 2000 engines)
5943947 (AR76)

Layshaft:
4346268 (says for all 131, 132 and Argenta)
4417998 (AR76)

Does anyone out there have a 131 Fiat Workshop Manual to confirm part numbers for my gearbox and or that the AR76 item is a direct swap?

[njgierszon]

I have been told on turbo124 forum

Late 131 gearbox uses:
Layshaft Fiat 4417998
Input shaft Fiat 4346271 (common to all 131 gearboxes)

I have also been told by an ebay vendor based in Italy
layshaft (campagnola) 5943942
Input shaft (campagnola) 5943947

Can anyone with a workshop manual confirm / assist?