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Re: [oletrucks] pinion flange nut question.

To: oletrucks@autox.team.net
Subject: Re: [oletrucks] pinion flange nut question.
From: Roger.Gleason@uconn.edu
Date: Tue, 22 Jan 2002 15:30:28 -0500
OK Listen up here! The crush sleeve is behind the front pinion bearing so
you would not see it.
You don't want to torque the pinion nut to 175 foot pounds unless you have
a new crush sleeve as it takes that amount of torque to crush the sleeve. I
would torque the nut until I felt a slight resistance and then measure it
if you have a inch pound torque wrench and can adapt it to the very large
pinion nut you can then take a reading. Tighten the nut and keep checking
until you get 12 to 15 inch pounds torque.  A note here is you can't
tighten it using the inch pound torque wrench. Only when refitting or
installing a new pinion or bearing set do you need a new crush sleeve. As a
matter of fact there will be some play or looseness in the existing set up
from wear. If your only changing the seal, and you tighten it slightly I
doubt it will hurt anything. It will change your back lash though, only
slightly. On a used set up you can be a little bit on the loose forgiving
side say 8 to 12 foot pounds and still be OK! If you have any other
questions ask I will be willing to help all I can.
Roger G





Let me explain a bit.

The in/lb rating you see/refer to is the amount of rotational torque needed
on the pinion bearings, measured without the axles or the ring gear
installed.

This is the pinion bearing preload.

In order to accomplish this, you need to add/subtract shims from the races
on the pinion shaft and tighten the pinion nut to 150-175 (or whatever
you spec call for) FT/LB.

Once the pinion nut is tightened to say 175FT/LBs, then you take a in/lb
torque wrench and rotate the pinion shaft (via the pinion nut) and measure
the required torque it take to maintain it spinning, not the amount of
torque required to start it spinning (which will be higher) but what it
takes to keep it spinning.

Again, if the amount is too low or too high, you need to add/remove shims
to get the correct torque.

You can see why you can't set the in/lb preload while spinning the axles
and ring gear... because the rotational forces applied by each will most
likely be more than the pinion bearing pre-load setting required.

  Now I've never set up an original TF rear, but have done a few Dana's and
Spicers from later model cars and trucks, the original TF rear is a bit
different as I recall, I'll look in one of my manuals to see if there's any
quirks.
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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