Morning Nath,
This is interesting. I just looked up the parts list for the yellow and yes, the 25" model had a 7/8" axle and the 28" had a 1" axle! I never knew that! I would have sworn on a stack of bibles that they would both have been 7/8" given that the Tractor series were all 7/8".
I wonder if someone has modified a 28" axle to suit your machine?
I did go and have a look in the shed and all my machines have 7/8" axles - but they are all 25". I measured the only axle I've got out (which is out of the very early machine and measured it roughly at about 645mm. I didn't measure the sprocket or count the teeth because it is different to all the others. It has a beefier chain so is a different pitch, I think. I'll drag one of the others out and count it but that'll have to be tonight.
I can pull the axle off the Red donor and send it if you wish. It's a different part number (GT154 vs GT916 ) but I'm not sure we can overthink that as the Red catalogue uses the same axle part number for both 25" and 28" with the footnote to state whether it's 25 or 28 inch.
I'm guessing you didn't get a useable axle with the second machine.
Cheers,
P.S. I haven't forgotten about the tool box
