I seem to be doing these every year. Maybe IÆm damaging them or not installing them correctly (crooked, not properly seated etc)

How can I make sure to do the job RIGHT?

Use a seal driver? How far do I drive the seal in? Extra careful when re-installing the axle?

Any hints and tips are extremely appreciated. IÆm going to be replacing the rear wheel bearings as they are growling at me (can a bad bearing be causing the latest leak, or is it likely the leak washed out the bearing causing it to go bad? Chicken or the egg?)

The only thing I'm pretty sure I'm doing correctly is greasing the rubber part of the seal before installation.

Thanks!

Yes, a bad bearing can cause a leak and yes a leaky seal can also wash out the grease in the bearing since the oil has to leak through the bearing to get to and past the outer seal.

If/when you get an oil leak, I'd recommend using a needle attachement on your grease gun, sliding it under the bearing seal lip and filling the bearing back up with grease when you replace the seal. Might be a good idea any time you have your shafts out for that matter (while swapping a 3rd, etc.).

That's a great idea with the needle attachment.

Marlin has some new axle seals with a lip that supposedly helps get them in there straight.

is the breather on your axel working properly? or is it clogged. If it is clogged it could be building up to much pressure and blowing out thre seals.

x 2 on check the braether.mine was stopped up causing pres to build up when it got hot and push oil out the seal.I replaced the stock breather with one off an old pathfinder and added enough hose to get the outlet out of harms way.make sure there are no low spots in the hose to trap moisture

I now have to think that your truck is cursed Mike and suggest an exorcism or replacement with a JDM 80 series...

Extended breathers working fine with no low spots. Thanks for the input!

I think it's been cursed for awhile. I blame all of the previous four owners of the truck

And don't you be tempting me with a sweet sweet JDM 80! I couldn't handle the happiness!

Besides all the other suggestions,a bent housing can cause a leak, a bent axle shaft can cause a leak.