Why Did M1008s Come with NP208 vs NP205s

[CARC686]

Doesn't the NP205 run gear oil? I know the NP208 runs ATF, which is the only reason I haven't been in a rush to replace the rear seal on my TH400, but if a transmission can leak ATF into a transfer case that's supposed to run gear oil, that sounds like it could be a rapidly developing problem.

 

[87cr250r]

Remember that automatic transmissions also have gears. ATF can lubricate gears. I always ran ATF in my dirt bike gearboxes despite them specifying gear oil. Twin Disc specs engine oil in their transmissions.

As robust as the NP205 is, I would suspect it would operate on ATF just fine.

I operate a lot of gearboxes in my industry. Helical and double helical have given way for palloid gears but the bearings haven't changed. Bearing race rotation has always been main failure in these boxes. Industry always preferred ISO 320 weight oils for protection of the gears which causes the bearings to fail and take out the gears with misalignment. We're running ISO 100 oils and everything is happier.

 

[CARC686]

Remember that automatic transmissions also have gears. ATF can lubricate gears. I always ran ATF in my dirt bike gearboxes despite them specifying gear oil. Twin Disc specs engine oil in their transmissions.

As robust as the NP205 is, I would suspect it would operate on ATF just fine.

I operate a lot of gearboxes in my industry. Helical and double helical have given way for palloid gears but the bearings haven't changed. Bearing race rotation has always been main failure in these boxes. Industry always preferred ISO 320 weight oils for protection of the gears which causes the bearings to fail and take out the gears with misalignment. We're running ISO 100 oils and everything is happier.

Palloid gears are sort of like twin perpendicular, helical-cut sprockets instead of a ring and worm? I never heard the word before now and Google image searches weren't particularly instructive.

 

[87cr250r]

It is a ring and pinion. It's a bevel gear with a helical cut. The centerline of the pinion is aligned with the axis of the ring gear. Maybe spiral bevel gear is more prevalent?

Truck differentials mostly use hypoid gears. They are similar but the axes are offset. The hypoid gear has some worm action which means sliding which is why they require special lubricants.

I operate and repair z-drives in tug boats. One ring and pinion converts horizontal shafting from the engine to vertical, and a second converts it back to horizontal. The housing rotates around the vertical shaft which allows us to aim our propeller 360 degrees.

 

[deank]

My copy of the LO shows dexron II for both the 208 and 205. I expect they might have typod for dex III