A few questions for you:

Do you wheel this hard? If so, you may want to look into so you may want to look into some 30-spline Birfields and axles. You can check them out here:

http://www.longfieldsuperaxles.com/

If not you may be able to get some used axles from Marlin Crawler give Marlin a call:

http://www.marlincrawler.com/

Did you see the axles and grooves? Not saying your mechanic is lying but I have worked on many Toyota solid axle front ends and have yet to see them grooved.

Do you know if he used the Factory Special Service Tool (SST) to set the front end up? If the knuckles are not properly centered with the shims, it can cause premature seal failure. Most shops do not have these or the mechanic's do not know the proper way of setting the front end up. The proper way of setting the front end up is covered in the Factory Service Manual (FSM). You can view it on line here;

http://www.lukemiller.org/toys/1985_toyota_4wd_front_axle_FSM.pdf

Add: I forgot about the bronze bushings, they can also cause problems if worn beyond spec. As stated above sometimes they need to be reamed, for some reason the last time I installed a set, I did not have to ream them.