Breathers for gear boxes, '72 710M

Diffs, axles, lockers, transmissions, portals, that kind of thing.
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JimmyC
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Breathers for gear boxes, '72 710M

Post by JimmyC » Thu Dec 20, 2018 10:43 am

I want to make sure my vents are good and high for my various gear boxes as I am thinking about a trip next summer with deep water crossings, say 30" or 40". My unit does not have breather units on the diff housings so I am thinking about adding those. I believe there is one on top of the transmission. I can't figure out how the transfer case or the portal boxes are vented. Can anybody give me a hint?
Jim Chance
710M

All my post fully incorporate the Dunning-Kruger effect

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rmel
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Re: Breathers for gear boxes, '72 710M

Post by rmel » Thu Dec 20, 2018 1:56 pm

Only the Differentials got vented, not sure when this was
introduced but the first year or two they were not.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

JimmyC
Posts: 181
Joined: Tue Feb 18, 2014 4:59 pm
Location: Lafayette, LA and Highlands, NC
Contact:

Re: Breathers for gear boxes, '72 710M

Post by JimmyC » Thu Dec 20, 2018 2:57 pm

I read somewhere that the transfer case is vented into the rear differential. I also read that on some later units the portal boxes are vented through the axles into the differentials. It is hard for me to see how a gear box could be unvented. There would be too much pressure across the seals with things getting hot and cold.
Jim Chance
710M

All my post fully incorporate the Dunning-Kruger effect

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rmel
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Location: Woodside, CA
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Re: Breathers for gear boxes, '72 710M

Post by rmel » Thu Dec 20, 2018 3:38 pm

Nope. You have nothing to worry about here. And its arguable if you have to vent your diff’s if they are not already. It’s really for pressure relief if there’s any pressure to speak of. I think this change came with the Ex-II diff gear improvement.

As far as the X-case goes it’s completely sealed except in the front for oil feed and return for the witches hat / locker. These two units are sealed with an O-ring.


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Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

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