Bronze Gear--troy Bilt

[dyanmix]

I was wondering why is a bronze gears used in a transmission in troy bilt? Isn't this a very soft metal ? I was thinking a hardened steel gear would last much longer. I know when I took my tine shaft out I could see all the tiny particles of shiny bronze in the oil. This is a sign of a soft gear metal...wouldn't you agree? :trink39:

[Dutch-NJ]

Bronze isn't as soft as you may think. Bronze gears have been successfully used for years.

But you shouldn't have too many bronze particles floating around. The particles may be caused by improper gear backlash or meshing, or improper or lack of lubrication.

Find out where the problem is. That may account for your seal problem too.

[JDFANATIC]

dyanmix,

There are as many bronze alloys as there are steel. Some can have tensile strengths approaching that of steel, some can be as soft as free-cutting brass. Some are oilite impregnated to improve lubrication, as do the leaded-bronze alloys.

[bontai Joe]

All the above is true as to the strength of bronze gears. Also gear drives work better and longer if the metals actually touching are different in hardness. A gear train of all hardened steel gears would soon self destruct as the surfaces each workharden from the contact of the other hardened surfaces. Having a "softer" surface with some "give" in it, will last a lot longer against a hardened surface. And as mentioned, proper lube is essential. Troy-Bilt used to recommend changing out the gear lube after "X" number of hours. I don't remember off hand how many hours that is, or what the current recommendation is if any. Mine (1980 vintage) was shipped with 140 weight gear oil in it, and it was recommended to replace it with 140W or 80W-120 at the lightest. Again, I don't know what the current recommendation is, but I know that 140W is not easy to find.