Heres a mystery, I have a life like FA and FB set, brand new, run very very little. There is an odd clunk sound coming from the B unit, and a lesser odd clunk sound from the A.
Checked posts and found a similar thread about Bachmanns Light Mountain, and in there they said a cracked gear… so off I went and disassembled the whole bang shoot, inspected the gears and lo and behold…Nothing, cleaned them up, lubed them and put them in, and then …clunk clunk same as before.
Anyone care to shed a bit of light? A local hobby shop says its the little brass square bearings, they look fine to me… Mysterious, or maybe I am just blind, either way , I am lost for answers.
PS On low speed the A has no sound clunk, but as we get up to speed it appears, the b has a definite shifty wobble witth its clunk from the get go.
if the wheels are the slittest bit loose in the gears (meaning you could turn em ) their gone, get some athearn gears for a sd-40 ,most train stores carry em. change ALL of them regardless if only one is cracked,you want all the gears to match .
some times its very hard to see the cracks thier very fine …Jerry
The easiest way to check for cracked gears is to put them between your finger and thumb and squeeze the very edge of the wheels together in a few spots.
The Proto 2000 GPs are notortious for cracked gears, but I have not heard of that as a problem with the FA and FB units. Could be a cracked gear problem, I suppose, for which the only cure is to replace the gear.
Don’t dismiss the hobby shop guy’s suggestion that it may be the little brass square bearings. If a bearing is slipping out of its seating, that could cause the noises that you are hearing. If the bearings are slipping out of place, you will need to insert a fiber washer on the axle to hold the bearing in place.
Just another thought - do the models have traction tyres on them at all?
I recently pulled out some old (late 90s, early 2000s) Roco models of French locos I’d received from my family in Europe. They still ran, but produced the same ‘thump-thump’ when running, and I quickly found that part of the traction tyres had cracked and fallen off. I know youv’e got new models, but the traction tyres might be twisted/out of shape/defective.
Don;t think the Proto FA’s ver had traction tires. However, if it’s one of the early ones, they have that goofy gearbox and rubber band drive to make the radiator fan spin. Perhaps that’s making some noise. Probably cracked gears though, especially if the loco thumps at all. I just use the Athearn gears as replacements.