Installation: ClearGearz 8.8" Clear Differential Cover

[ExplorerDMB]

That could simply be because the plastic is not as good of a conductor of heat as the metal ones are.

Metal conducts heat better, granted -- but the plastic/polycarbonate allows the heat to disperse and not be on the fluid. I could guarentee that the temperature inside the pumpkin is less than it was with the metal one.

-Drew

 

[TheRookie]

On note I would like to add about install. Do NOT use a wizzard wheel to rough anything up. A wizzard wheel is used to CUT metal. its a 3 inch Cutting disc and will do major carnage. You may use something as minor as a scotchbrite pad for this. Or a mini die grinder with a sanding or scotchbrite disc.

 

[j602]

Methinks he might have meant a wire brush wheel for a drill/grinder.

 

[TheRookie]

Perhaps an edit is in order then

 

[99SportX]

This might be a dumb question, but where is the filler hole for the fluid? How do you fill up the differential?

 

[spindlecone]

DO NOT touch the milled surface with any abrasives, scrap off any obvious stuff with a blade, some scotchbright and a little lacquer thinner will clean all up as new.

 

[Jefe]

This might be a dumb question, but where is the filler hole for the fluid? How do you fill up the differential?

The 8.8 has the fill plug on the housing, to the passenger side of the pinion.

EDIT: drivers side, not passenger side

 

[gijoecam]

...but the plastic/polycarbonate allows the heat to disperse and not be on the fluid. I could guarentee that the temperature inside the pumpkin is less than it was with the metal one.

-Drew

No, it does not. Heat Transfer 101. The thermal conductivity of any standard polycarbonate will be less than the conductivity of steel. If the gear oil is a constant 150 degrees, the metal cover will feel hotter than the polycarbonate one. That's not because it's wicking more heat out of the oil and radiating it, it's because it's not conducting as much of the heat from the oil to the air. If you want the ultimate in thermal conductivity, you would make it out of copper. The thermal conductivityof a standard polycarbonate is 0.196 W/m-*K, whereas a plain 1010 carbon steel has a coefficient of 63.9 W/m-*K. Pure copper is 401, but for the ultimate in conductivity, nothing beats pure silver with a thermal conductivity of 429 W/m-*K. Of course, a pure silver cover wouldn't last long on the trail and I'm sure would be tough to keep from tarnishing.

Industrial diamone makes a pretty good thermal conductor too.... 2300 W/m-*K Unfortunately finding an industrial diamond large enough to turn into a diff cover could prove quite costly and probably quite difficult to come by.... I'd hate to have to call a jeweler to change my gear oil.... I wonder what they charge for that?

-Joe

 

[ExplorerDMB]

Perhaps an edit is in order then

I have deleted it all together. It was just a tip for a better seal. It was a 90 degreed die grinder that I used. We just call it a wizz wheel at the shop. Sorry for the typo -- it's deleted now!

-Drew

 

[IZwack]

The 8.8 has the fill plug on the housing, to the passenger side of the pinion.

EEEP! mine is on the driver's side of the pinion - near the gas tank.

 

[spindlecone]

SOOOOOOO we are talking Kilopascals here? where do's AL fit in as a conductor of heat?

 

[ExplorerDMB]

EEEP! mine is on the driver's side of the pinion - near the gas tank.

That is where mine is as well. If you are under the truck with the gas tank on your right...it is on the right of the pumpkin.

-Drew

 

[IZwack]

SOOOOOOO we are talking Kilopascals here? where do's AL fit in as a conductor of heat?

Watts per meter squared-kelvin. Pascal is a pressure unit (force over an area: Newtons per meter squared)

AL is about 230 W/m-*K ... not too bad.

Id like to add that most of us have a differential cover with layers upon layers of paint.. some are even undercoated - which obviously helps to insulate the heat.

 

[spindlecone]

Watts per meter squared-kelvin
Pascal is a pressure unit (force over an area: Newtons per meter-squared)

I knew that back to AL as a conductor (not Aldive)

 

[IZwack]

I knew that back to AL as a conductor (not Aldive)

Oh, I edited my post with the AL thermal conductivity

 

[spindlecone]

Great info, thx IZ, always willing to learn

 

[IZwack]

always willing to learn

Thats what we're all here for after all - to learn

 

[gijoecam]

Watts per meter squared-kelvin. Pascal is a pressure unit (force over an area: Newtons per meter squared)

AL is about 230 W/m-*K ... not too bad.

Id like to add that most of us have a differential cover with layers upon layers of paint.. some are even undercoated - which obviously helps to insulate the heat.

True, but if my memory serves, the paint affects the emissivity more than the conductivity.... has to do with the surface finish. (I don't recall how much of an effect it has, just that it does)

And yes, my book has pure aluminum as being 237.... 2024 T-6 Aluminum alloy is 177, 195 Cast with 4% Cu is 168.

I've got too much spare time....

-Joe

 

[the_tool_man]

Great writeup:

Just be careful what you use to clean that polycarbonate cover with when you take it off next time. Acetone, Laquer thinner, and most brake cleaning solvents will craze the surface, turning it white almost immediately upon contact.

Regards,
John.

 

[Jefe]

EEEP! mine is on the driver's side of the pinion - near the gas tank.

Ooops. . Its been a while