I installed a new outer pinion bearing and seal on my small case 3.91 LSD diff and tightened the nut to the previous marks that I had made. Right now the friction torque is maybe 5-7 inches when I measure it with the beam style torque wrench. Is there a default range I should be using for the torque rating? I see the metric mechanic site is using 14 to 16 inch pounds?
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Diff pinion bearing preload torque spec?
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There are 2 specs- one for new bearings, and one for used.
I forget both. But the mm number seems right for a smallcase new bearings.
The used bearing number was less- maybe 7-10? I forget. I found it
in the E21 service manual. Which is... err... I forget where that is...
If it was mine, I would tighten it to 10 inch-lbs of drag, run it for a while, and recheck.
What I found, seat- of- the- pants, is that for whatever reason, sometimes with new
bearings they could loosen more than I'd expect. Usually not a lot (10 degrees of
the nut, or not enough to lose all preload) but I did have one get loose enough to where
it clicked if you wiggled it. Caused all sorts of driveshaft vibes, too.
I was using them semi- disposibly in a 2002 race car where they went in and out
depending on tracks, so it was easy to check, and snug just a bit if needed.
hth, just a story.
tnow, sometimes I just mess with people. It's more entertaining that way. george graves
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