Some did I noticed them more on the Afx chassis(es) with the overhead lights.

 

That is a Magnatraction Specialty chassis.

http://www.modelmotorist.com/web-content/afxspmtl.jsp

 

Your link points to A 4 gear chassis, the chassis in question appears to be a 3 gear.

 

Didn't the original MagnaSonic chassis have that cluster gear?

 

I do not think those are custom. Out of the 200+ AFX and MT top plates that I have on complete cars and on torn down parts, I have seen two with that type of cluster gear. No idea what type car they came with, but they must not have made very many of them.

 

Oops, it is not a Specialty chassis. It looks like a regular Magnatraction car with a Specialty driven gear and that combination is not shown on the Model Motorist site. It still looks like a production chassis, maybe they were just using some leftover parts and only made a limited number of these. I will pass this along to Bob Beers, he wrote the book on Aurora cars.

 

It's not a specialty rear combo gear which I think is a 20T. It is a 24T rear combo gear same size as the standard 3-gear rear gear. The only difference being the retaining plate molded to the top of the gear.

(am I using the word 'gear' enough?).

 

I have more cars with them than without

 

I don't have access to my chassis right now, but .....
the overheads AFX chassis might have used such a set up because the idler gear is part of the flashing unit I think.
also, the AFX chassis that had that sound box with a sepcialized idler gear might have used that driven cluster also.
I cannot think of other applications that might have needed a specialized cluster driven gear.

 

I think Al has at least one of the answers... if my memory serves me correctly these were mounted on the MagnaSonic chassis. Since most of us found the MagnaSonic cars quickly became annoying, the soundbox was removed and replaced with a standard gear plate clip and the unique rear gear stayed.

Gary
AKA LeeRoy98

 

The MagnaSonic cars that I have seen pictures of have regular driven gears.
http://www.modelmotorist.com/web-content/afxmsl.jsp
http://www.modelmotorist.com/web-content/afxms2l.jsp

I did contact Bob Beers about these cars and he tells me that he has not seen them, which makes it more likely that they are hybrids.

 

I had two BMW M1s white/red/blue that came with that gear?I think that the above statement is very true,the odds of finding those are around 200-1.I have 389 cars and have found two of those arm plates.

 

I've never had onion a magna sonic chassis but they might have been on some. I've seen them almost all the time on a chassis with overhead lights as I stated before.

 

I have quite a few with that style of gear..