Stock rear end?

[svr]

I Traded a 2 ton all steel flat bed and some cash for a 57, 3100, short box basket case. It is in primer and most body work has been done, steel is pretty sound. It started life as a navy pickup then went to a local school district for many yrs. Anyway trying to make a plan, Going to leave the 235, it seems to run fair enough to get started. Going to swap out the 3sp for and s10 5sp with .72 over drive so I figure i need a rear end in the 3.90 to 4.10 range and thats what the stock gears should be. Question, inspecting the rear end I found a small hole maybe 1/8" or so in the top of the left axle tube. It appears to be an open hole, was there a vent of some sort there? Or has somebody done this for what ever reason. Thanks

[mr48chev]

Without looking at the 55 rear I have for a project I couldn't say but it is either for a vent or a hole for a fastener to hold a clip to hold the brake line.

[1project2many]

That should be the vent.

[svr]

Anybody have a pic of what the vent should look like?

[dsraven]

those are usually a 1/8 pipe thread into the axle tube. you could google it for a pic. some have a longer "bolt" because some OEM's use them to hold the "T" for the brake fitting. some guys will install a simple 1/8 pipe to hose fitting then use a short length of hose to get the vent tucked up and away from road dust or lake water etc.

[_Ogre]

this is similar to what should be in there
my first job as a lube monkey required that we rotate the cap every time we were under there
small fitting with sheet metal cap crimped on
the cap is loose to allow air to breath as the rearend heats and cools
if the vent gets plugged with dirt the pressure comes out wheel seals or the front main seal

[svr]

That looks familiar Ogre, Thanks guys