Differential options for '74?

[das]

Hey all,

my 74's differential is howling like a wolf. My mechanic replaced the fluid and tightened the bolt, but its still wailing.

what are my options to replace? I know I can replace with a 74 diff, but
is there a direct bolt on upgrade available from a later model spider or other alfa that will make improvements?

let me know...

thanks

[Alfajay]

das:

1) Are you sure the howling is coming from the diff itself, and not one of the outer bearings? Differentials usually last forever (unless they run out of oil), while the bearings do go bad. The bearings are retained on the outer part of the axles by a pressed-on sleeve - replacing them isn't a big deal. You might try turning each rear wheel, feeling for play, or listening for growling, to diagnose the noise a bit more.

2) All 2L Alfas can interchange differentials. So any '72 - 9X diff from a 4 cyl car will fit.

3) You lost me when you said "upgrade" - what kind of an upgrade are you looking for? 90% of all diffs out there will have a 4.56 ratio (your '74 almost certainly does). Later spiders from the EFI era had 4.10's, and I believe that spiders with automatic transmissions used a 3.XX. But, it's debatable whether a lower numeric ratio is an "upgrade" - depends on how you use your car.

[das]

thanks Jay

- I'll check the bearings, thanks...
- Good to know
- Didn't realize I already had the 4.56 ratio, no need to change then