Topic: diff guard opinion.

[stan98tj]

Many axle places I know of tell you to NOT use synthetic for a ring and pinion.

really? i wonder why. perhaps i should switch to regular.

[Jeffy]

Many axle places I know of tell you to NOT use synthetic for a ring and pinion.

For initial break-in you're not supposed to use synthetic.  You need the friction to finish the peening process which was started at the factory.  Afterward it's OK.

[stan98tj]

For initial break-in you're not supposed to use synthetic.  You need the friction to finish the peening process which was started at the factory.  Afterward it's OK.

well its been 110k miles since it left the factory, so i should be good.

[dwtaylorpdx]

For a long time, the regular gear oil had a high sulfur-zinc content that really helped keep the
gear surfaces tough, now that its gone my theory is the synthetic is better.

There are a few brands that sell break in oil that's really just the stuff
with the extra zinc for break-in... With a only use to break in disclaimer.

Dave