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TR2/3/3A TR3 Rear End Oil [Again]

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Mickey Richaud

Mickey Richaud

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OK - I should know this, but have to ask: Is synthetic oil safe to use in differentials? Can't seem to find Hypoid oil locally, and I need to change mine out (I'm afraid it's got some GL-5 in it - hope there's no damage).

Mickey
 
Hi Geo & Mickey,
Nothing in the rear end, that I am aware of, would be harmed by use of GL-5. Since it IS hypoid, it could well benefit from using GL-5. It's just not such a good idea in transmissions with brass synchronizer rings.

GL-4 & GL-5 are specifications. Both synthetics & non-synthetics are available in either rating. GL-5 has more sulfur additives in it which help it resist the very high sliding pressures that occur with hypoid gears. As mentioned, the high sulfur content of GL-5 is thought to degrade brass components in transmissions.

Likely, it would take years for GL-5 to actually damage brass transmission parts, but why take a chance?
D
 
Thanks, Dave.

So, since the factory specs call for 30W for the gearbox, any good motor oil is fine there (I intend to use Castrol 20W5 when I change it out). The differential should have GL-5.

Sorry about the confusion, but I was looking at an earlier post, and got some conflicting information (imagine that!)

Thanks again,
Mickey
 
FWIW our local Checker Auto Parts (may be Kragen or Schucks in Tenn) regularly carries Castrol GL5 in shorts & quarts.
 
Thanks, Geo, but we don't have either of them here. And any Castrol product other than motor oil is hard to find here. No matter, though, as I may be going with synthetic for the diff. anyway.
 
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