Overland Models E7 Diesels (truck binding)

[ChristianJDavis1]

I believe that all of the gears in the truck are the same black plastic, so metal seems like an okay choice. I'm still wondering why only those two gears cracked, though; same one on each model. Coincidence, or is there a certain amount of stress on that specific spot? Will the others likely follow suit? I was going to try and remove them then figured "why tempt fate?"

[mmagliaro]

I believe that all of the gears in the truck are the same black plastic, so metal seems like an okay choice. I'm still wondering why only those two gears cracked, though; same one on each model. Coincidence, or is there a certain amount of stress on that specific spot? Will the others likely follow suit? I was going to try and remove them then figured "why tempt fate?"

I can't say why only those two cracked.  The ones on the other axles are probably the same gears and the same axle stock.  It could be that those axle positions in the gear train experience more stress that we just aren't aware of.  I can tell you this.  If it were my engine and I were ordering custom-made gears to repair it, I'd order enough to do all the axles, plus a couple of spares.  I wouldn't change the good ones, but I would want to have gears handy in case those other ones fail.  They are about $6 a piece in brass.  If you need 6 to do the whole engine, that's $36, a little pricey, but not too bad.   It's a brass engine after all.   

[ChristianJDavis1]

Yeah, for models I have nothing invested in, $36 per locomotive does not seem like a bad price to pay.