differential leaking

[1973olds98]

i have my 73 olds 98 up in the air ready to undercoat it...I noticed the pinion seal leaking,,,,I dont seem to see the drain plug..i see the plug to fill it and check fluid level...Am i missing something or is there no drain plug...Also how hard is it to change the seal...

[J-(Chicago)]

There is no drain plug. You will have to pull the cover to drain the old oil.
As far as fixing the pinion seal...... Well, I can get you by with a 1/2 arsed fix for it. The proper way would be to pull the gears, fix the seal and retorque the pinion gear nut with a new crush sleeve.

For the cheap back yard fix, you pull the driveshaft and yoke off, pop the old seal out, pound the new seal in and retorque the pinion nut until you feel the crush sleeve mush down a little more. It's hard to do this by yourself because it requires about 200 lb ft of torque. I used a 24" pipe wrench braced against the pavement on the yoke, and a long breaker bar with a pipe on the end to tighten. The yoke should feel like a really tight door knob when you turn it by hand with the wheels in the air.

Don't make it too tight to where it won't turn, or you will definitely have to pull it apart and re do it.

[1973olds98]

would a air impact tool work,,also is there breather/ vent on the Diff

[J-(Chicago)]

Chances are, no. Unless you have an industrial one for changing semi truck wheels or the like. Plus an air impact won't give you the "feel" that you will need. There is a breather.

[1973olds98]

so basically you used a pipe to hold the yoke from spinning while you tightened the nut correct...I am going to go ahead and attempt this tommorrow,,,,I am gladi found the leak,,,who knows how longs its been leaking..Its pretty gunled up all around the front of the housing and down the sides....Where is the vent,,I read I need to make sure it isnt clogged..Also how much fluid does it take to fill back up...thanks for your help..

[J-(Chicago)]

I used a pipe wrench to hold the yoke.

Probably 2 quarts to fill it.

[monzaz]

The vent is on the passenger side of the upper cast webbing area just under and around the passenger upper control arm casting boss. Some times they cake themselves to almost undetectable buried under its own oil goop.

As far as the pinion crush sleeve just snug that nut. The crush sleeve is already at the distance it needs to be for the bearing pre load. Snug it up do not worry about torque that is only what it takes to CRUSH the crush sleeve not what the NUT needs to be at on a re torque. As stated you really need to replace the crush sleeve to be proper...BUT were going to get you back on the road.
after you get the pinion nut snugged enough to get that slight drag (20-25 foot lbs. on a consistent spinning torque wrench spin) That is hard to do under the car... so use your feel here. After you get that done, STAKE the nut into the thread with a pointed steel punch and hammer in about 2-3 spots this will hold the nut from backing off and should get you back on the road again. Jim

[1973olds98]

i picked a new seal up from autozone for 7.99 and me and my uncle replace the seal a few ours ago,,it was pretty easy,,,hopefully the leak is fixed...i am glad i found the leak because the fluid level was quite low