I think 85/140 is a bit thick for minitruck diffs. Thick != lubricity nor shear strength, just more stuff to sling. Do the calcs: how many *millions* of miles have been put on minitrucks (even running 5.29s!) using dino 80W90, with NO issues? Now add BG MGC, and use Valvoline dino 80w90 or Valvoline Durablend 80w90 (not a bad price at all), and you have... a winning combo IMHO. I happened to use Redline Heavy Shockproof (still 80w90) cuz I had a gallon sittin' around just looking expensive. Valvoline wuz gonna go in there.
It could be a combo situation too, with tire tread, u-joints, splines and just the right amount of something in the diff, made audible by all the (appropriate) play in the driveline. Put the diff in another truck and you might have silence. Plus, put your hardtop back on and you might hear... nothing. Add a different shim and alter your driveline... same outcome.
Run it for 500 miles varying speed and temperature, do the hypoid drain maneuver, and check your drain plug for chunks. No chunks, no increase in noise (beware the audible hallucination dynamic when you are looking for something and are 'just sure' you heard it), run whut ya brung.
Like I said, *you* make *me* look non-anal! And that is an accomplishment of which to be proud. I just completely disassembled a diff and locker, chasing what turns out to be an emergency brake cable issue. *THAT* would be *anal*.
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.
Last edited by Red_Chili; 10-04-2005 at 08:30 AM.