Lincoln's PowerLuber cordless grease guns are used in automotive, agricultural, and industrial maintenance to deliver consistent grease volume without hand pumping. A pump piston seal leak usually shows up as weak pressure, grease bypass, or mess around the powerhead-often fixable with seal service and inspection of the check valve and hose.
Repair is usually worthwhile if the motor still sounds strong and the issue is isolated to seals/valves, since these parts failures don't necessarily imply broader electronic damage. Replacement is more sensible when the unit has chronic pressure loss after seal replacement, a damaged powerhead, or cracked housing from drops, pushing repair costs near the threshold.
Price used is a common retail price for a PowerLuber cordless configuration; kits and higher-capacity models can cost more.