94 Toyota Truck Rear

My 94 Toyota SR5 Pick Up just had the rear replace for the 3rd time in less than six months. It has 375,000 miles on it and had 372,000 miles on the original rear, but the replacements/used rears only seem to hold up for a month before it goes back to the shop. It has the larger tires so the gear ratios required ar hard to find. Any similar problems out there, words of wisdom, help in any form or should I just put her down?

You need to find a rear axle that isn’t just as worn out as yours…You may need to do the leg-work yourself.

Does this axle have a removable rear cover?

What are the presenting symptoms when “it goes back to the shop”? Has the mechanic determined if the gears are failing or if one of the final drive bearings are failing? Is the failure always the same?

Usually, if the rear end works initially and is quiet for a month and if the correct lube is in the rear, that rear will go a lot a miles before a catastrophic failure occurs.

Why put a used rear end in? You had a used one to begin with. Ask around and find a reputable local independent shop that will repair or rebuild yours. Parts are still available and your differential is quite simple for anyone who’d done that kind of work.

Is the replacement rear end being filled with gear oil after installation? And if it is a removable carrier is the entire axle being replaced or only the chunk?

Exactly what’s failing?
Seals? Pinion & ring gears?
I guess at this point I’d be looking at simply rebuilding the existing rear end. Is that an option for you?

Thes “larger tires”…are they stock size?