Leaky Differential

[Alk-3]

Hey All. my rear differential has suddenly developed a pretty bad leak at the drive flange oil seal. My thoughts are of course that the oil seal needs to be replaced, but since the leak is so sudden I thought maybe the breather has been clogged and is building up pressure when hot (it only leaks when it's hot (in use) but stops after its parked and cools off). i took the axle breather off and cleaned it, but no improvemnt.

Quick few questions:

Is the breather for the differential the one on top of the axle?

Is the oil seal difficult to replace? Does it require me to remove the differential from the truck?

my truck is a 1967 88". Is the standard differential a 4.7:1 ?

[o2batsea]

Hey All. my rear differential has suddenly developed a pretty bad leak at the drive flange oil seal. My thoughts are of course that the oil seal needs to be replaced, but since the leak is so sudden I thought maybe the breather has been clogged and is building up pressure when hot (it only leaks when it's hot (in use) but stops after its parked and cools off). i took the axle breather off and cleaned it, but no improvemnt.

Quick few questions:

Is the breather for the differential the one on top of the axle?

Yes

Is the oil seal difficult to replace? Does it require me to remove the differential from the truck?

No and No. Remove drive shaft, undo big nut, pull out drive yoke, pry out seal. Inspect yoke. It may have a groove worn in it. If so a new seal will quickly wear out. Replace yoke if necessary. Fit new seal, be sure it is bottomed out. Fit yoke, replace big nut, refit drive shaft.

my truck is a 1967 88". Is the standard differential a 4.7:1 ?

Yes

[slowmo]

Be sure to chock the wheels in both directions. When you take off the drive shaft the transmission brake will do no good unless you have it in 4 wheel drive with the front hubs locked. Before the "big nut" breaks free your efforts will result in the truck rolling.

[o2batsea]

Be sure to chock the wheels in both directions. When you take off the drive shaft the transmission brake will do no good unless you have it in 4 wheel drive with the front hubs locked. Before the big "nut breaks" free your efforts will result in the truck rolling.

And torque farts

[Alk-3]

Thank you guys!