3rd member talk (ring&pinion setup etc.)

[NoHachi]

Some helpful links and info:

Quote:20.1.2 Splash Lubrication
Splash lubrication is used with an enclosed system. The rotating gears splash lubricant onto the gear system and bearings. It needs at least 3 m/s tangential speed to be effective. However, splash lubrication has several problems, two of them being oil level and temperature limitation.
1. Oil level.
There will be excessive agitation loss if the oil level is too high. On the other hand, there will not be effective lubrication or ability to cool the gears if the level is too low. Table 20-2 shows guide lines for proper oil level. Also, the oil level during operation must be monitored, as contrasted with the static level, in that the oil level will drop when the gears are in motion. This problem may be countered by raising the static level of lubricant or installing an oil pan.
2. Temperature limitation.
The temperature of a gear system may rise because of friction loss due to gears, bearings and lubricant agitation. Rising temperature may cause one or more of the following problems:
- Lower viscosity of lubricant.
-Accelerated degradation of lubricant.
-Deformation of housing, gears and shafts.
- Decreased backlash.
New high-performance lubricants can withstand up to 80 to 90ºC. This temperature can be regarded as the limit. If the lubricants temperature is expected to exceed this limit, cooling fins should be added to the gear box, or a cooling fan incorporated into the system.

Quote:Worm gear lubrication
Worm drives are inefficient because the gears experience sliding rather than rolling contacts, leading to operating temperatures much higher than other gear types. Spur gears normally operate at 28°C higher than ambient temperatures while worm gear temperatures typically rise 50°C over ambient. This temperature difference is required to aid in dispersing the friction heat generated.

Due to the sideway sliding motion in worm gears, it is difficult to maintain a hydrodynamic oil wedge. This results in gears operating under boundary lubrication conditions. Also, high operating temperatures that approach 88°C and higher usually require oils with an ISO VG of 460 and higher. They also require good thermal and oxidative stability. The types of oils used to lubricate worm gears are compounded mineral oils, EP mineral gear oils and synthetics.

http://www.roymech.co.uk/Useful_Tables/D...ation.html
http://www.qtcgears.com/Q410/QTC/Q410P441.htm
http://www.machinerylubrication.com/arti...icleid=707
http://www.khkgears.co.jp/english/teach/KHK342_1.html

Judging from this info..both factors may be influencing ring gear failure, but temperature failure is most likely.
Also see the remark in one of the links about shockloads. Ordinary gear oild cannot handle the extreme stress from shockloads. In these cases synthetic fluid MUST be used..Now I am sure synthetics come at their own cost, but I'm too busy to find out now.