Gearbox interchangeability

[Angle Grinder]

I've got a noise coming from the gearbox which I assume to be worn layshaft bearings. As a possible replacement / parts donor, I bought a gearbox from a chap who is relatively local to me.

My initial intention was to re-build the original gearbox using the spare box as a source of parts, but I am now thinking that I might as well stick the spare box on just to see if it is a good one. This would obviously save a lot of time and money if the God's of good mechanical fortune were to smile upon me.

However, I am now having doubts about the interchangeability of the gearboxes. For starters, the original gearbox has P/N 815 331 (Serial no. 937) and the spare box has P/N 815 533 (Serial no. 208).  

But there is another difference, on my original gearbox the dipstick sits in the box right up to the "hilt" of the plastic dipstick. However, the same dipstick inserted into the spare box will not fully insert and there is a gap of ~1cm between the hilt of the dipstick and the surface of the gearbox.

My Flavia is a 1967 1.8 (Carb) coupe. Can anyone offer any information about which gearbox Part Numbers should be compatible?

P.S. I am guessing that the 815 533 box has come from a Flavia Zagato so the 4th gear will be a bit higher.

[brian]

I will check my spare coupe box with the spare Zagato and see. Although on reflection as I was about to hit the send button it may be a 1500 one! I have Parts Books and will look there.

[Angle Grinder]

Thanks Brian, that would be appreciated.

The difference with the dipstick is a bit strange, but the dipstick that came with the box (not necessarily the correct dipstick either) doesn't fully insert to the hilt either. Maybe the different gear sizes for the 4th gear meant adjusting the dipsticks "funnel" so that it cleared the larger diameter cogs. Who knows?

Be good if I could source a replacement box that was known to be trouble free as a gearbox swap is a lot more appealing than trying to do a rebuild.

[brian]

Very sorry to be so slow in responding but life had overtaken Lancias.
I checked my spare 815-533 box and my 815-130 box (ie 1500 cpe) have different dipstick/breather. The older one is a nicely made metal one and the later one is all plastic but they both fit the other box and the marks are the same depth. The parts book gives the same picture and number and origin (815.00) for both cars.
Hope this is helpful.
Brian.