TMR vent bellow kit

Anybody using one of these instead of doing to rear diff breather mod? Seems easy and no drilling or other hassles. Anyone?

http://www.tmrcustoms.com/store/index.php?main_page=product_info&products_id=1075

 

The amount of expansion permitted by the bellows is insufficient, simple as that.

The diff oil (and therefore the air in the diff housing) can reach over 100C. Assuming the air starts at -10C (easily reached in Canadian winters), then the volume expansion is 373/263-1 = 42%. Rear diff oil capacity is 2.95L. Since the fill plug is about half-way up the housing, we can estimate about the same amount of air is in there. That means the bellows would have to expand by 2.95x42% = 1.24L to avoid pressurizing the diff housing. Clearly the part is too small to do that, so you'll end up with axle seal blowouts.

 

212 Degrees F. I think you would be pushing or towing pretty hard to reach those kinds of temperatures.

Rule of thumb is you can keep your hand on the housing it is less than 120 degrees F. I have never seen it so hot that I could not keep my hand on it.

My 2 Cents.

 

I keep one in my truck. If I ever have the need to cross deep water I can throw it on qwik. I had it installed for a little while but i didn't like the pressure that built up in the bellows.

Fwiw, I noticed my stock breather seemed to have a one way valve on it...it only seemed to let air out, not in. Thought that was weird.

 

Wicked, nice to have undeniable math to know that the mod is useless. :-D

 

What i never understood about the diff breather on there stock, as well as the lil breather people use to extend it, is the fact its a one way valve, wouldnt you want it to let air in and out?

 

Actually when it starts to get sucked down it can draw air through the seals. They only stop fluid from getting out.