Torque King in Billings Montana has a special tool to facilitate inner axle seal replacement.
Basically a jack screw with aluminum plates the size of the seal.
I am sure you could fabricate one.
Did mine when i replaced ball joints,axle joints etc.
You will need a case spreader to get the carrier out.
On a used axle with old carrier bearings it tends to be easy to just pry the carrier out with a crow bar.
Hammer it back in with a singlejack and block of wood.
But, that isn't the proper way...
I bought all the tools.
Recall it was about $150 for the inner axle seal tool and i think my case spreader was under 100 bucks.
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Ball joint press
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Inner axle seal tool
The case spreader is buried in my tools somewhere but it is just a square frame of steel with two pins and two jack screws.
It spreads the diff case about .010"
Just put everything back the way it came out, shims etc.
If your axle was in good shape before then removing and replacing the carrier will have no ill effects.
It's really easy.