Re: Another Engine Swap Question

[jlandry@domain.elided (John A. Landry)]

As the little green aliens inserted a searing hot probe into the sternum of
n9ads@domain.elided (Howard R Pletcher), a blood curdling scream was heard...

>In the Track-Lok, the cross pin is rigidly mounted to the diff case like
>the open diff, so the only LS action comes from the clutch preload.

Howard,

I'm not trying to nit pick, but in the interest of our continuing education
and information accuracy, this is not the entire story on the Trak-Lok... at
least according to IH.  It takes careful reading of what IH said in the shop
manual to pick up the second part...

"The multiple disc clutches with radial grooves on the plates and concentric
grooves on the discs are engaged by a preload from Belleville springs PLUS
SEPARATING FORCES FROM THE SIDE GEARS AS TORQUE IS APPLIED THROUGH THE RING
GEAR."  [Caps are my emphasis.]

You see, the side gears are free to float inward or outward on the ends of the
axle shafts (inside the Trak-Lok carrier), so as torque is applied through the
ring gear (and the axle shafts resist turning), these side gears will
naturally want to ride up and away from the pinon mate gears.  This tendency
of the side gears to want to separate and move apart from the pinon mate gears
causes the clutch packs to be compressed between the rear of the side gears
and the inside of the Trak-Lok carrier housing.

This is why under certain circumstances IH specifically recommended applying
the parking brake to obviously help begin the gear separation and clutch pack
compression process.  Under "UNIT INOPERATIVE" the manual says...

"3. If extremely slick surfaces such as ice or grease are used, some question
may exist as to proper performance at step 2.  In these extreme cases a
properly performing limited slip differential will provide greater "pulling
power" by lightly applying the parking brake."

However, having gone over all that, I tend to think this whole gear
"separation" thing in the Trak-Lok is probably not *nearly* as effective as
the direct and positive pressure applied by the camming action in the Powr-Lok
differential.  By visual examination, the clutch packs in my Traveler's
Trak-Lok are quite loose (under no load) and undoubtedly are well worn out.  I
have no reason to doubt I have the original Trak-Lok on a truck with over
200,000 miles on it.  With all the snow we got here in WA state this past
week, I had the opportunity to test this sloppy old Trak-Lok with one tire on
bare dry pavement and one tire on glare ice.  Even with the parking brake
lightly to moderately applied, I couldn't tell any difference than without it.
The tire on the ice spun happily just as if the diff were open, while the one
on dry pavement stood still.

I plan to rebuild my daily driver's Trak-Lok and also a spare from my parts
Traveler this next summer.  I'll install both back into my daily driver -
front and rear.

Happy holidays,

John L.
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