P & W Shops

Why?

 

    Most Woodings owners are, or should be, aware that Series "8" gearboxes have a weak

link. That weak link being that when their car is being operated in the forward direction,

the gearbox is actually being run in the reverse direction, that is to say, running through a

small reverse idler gear in the gearbox. Because of cost, space, or design limitations,

many gearboxes are built to operate with this "derated reverse" condition. Woodings, for

whatever reason, in their Series "8" design, overlooked this detail. That oversight has

proven to be the Series "8" gearbox undoing as there are many junk series "8" gearboxes

out there because of failed reverse idler gears.

 

    During the 2008 season, I was having a discussion with a fellow Wooodings owner

about the "derated reverse" series "8" condition when it was suggested that if Woodings

had redesigned the rear end drive to put the crown gear on the other side of the pinion

the problem would have been addressed. It was one of those "ah hah" moments, why not

flip the rear end, it would accomplish the same thing. Our stretch Wooding (ATSF 100)

with its' additional weight and horsepower would surely shorten the life of our newly

rebuilt series "8" gearbox, so this was our candidate for this modification.

 

    Careful examination of the rear end design and geometry indicated no insurmountable

problems. It should be noted that this mod was accomplished in about ten man hours and

cost less than twenty bucks. It should also be noted that our car has a steel rear axle

support, rather than the more common aluminum.  We are planning this mod for our

NEGS 100 CBL, with its' aluminum rear axle support for this coming winter. Again, there

appear to be no insurmountable problems. No modifications what so ever were necessary

to the rear axle or its' castings.

 

 

    Rear end on the "bench"?? Note that the flip will now put the cover on the underside of

the rear end. It should be noted that because the cover will now be down, and rear end

lube always present at the gasket, a good seal will be necessary. The fill plug will now

become the drain plug and provisions will have to be made for the vent. The vent was

removed and a plug installed in the hole. The cover was removed and the mating surfaces

cleaned and degreased, also any surface burrs were removed. The gasket, in good shape,

was cleaned and re-used. The cover was re-installed using copius amounts of gasket

sealer on both sides of the gasket as well as the casting mating surfaces. We chose to

use Permatex "Aviation" gasket sealer, sometimes called "Indian Head". Although messy,

we have had good success with this in the past. The sealer was allowed to set up

overnight, the outside surfaces cleaned, and a bead of silicone applied to to the exterior

seam for extra measure.

 

 

    In order to maintain the existing driveshaft geometry, it was necessary to modify the

support frame. Cutting this clearance hole allows the rear end  to rotate back up to its'

original position thus maintaining the original driveshaft angle without modifying the rear

end casting. It should be noted that universals in the drivshaft make this unnecessary

but it was felt that doing so would make for less vibration and wear and tear on the

universals.

 

 

  

Reattachment  was acheaved by using modified bolts to the old mounting boss. Although

a more elaborate means of attachment could be done with the fabrication of a new

bracket, we deemed this arraingment to be adequate.

 

 

 

Underside view of the re-installed rear end.

 

 

Top side view. Note the combination fill/vent plug. This was fabricated from off-the-shelf

components purchased at the local Home Depot. It was necessary to purchase a 7/16 tap

and apropriate drill to re-tap one side of the brass coupling so the IPS and compression

thread sizes would come together properly. This new combination fill/vent screws into

the old drain hole.

 

    To date, 6/07/09, we have put 300 or so miles on this new arrangment with no issues.

No leaks, no vibrations, no problems what so ever. We deem this mod to be a success.

 

    End of season evaluation, 11/14/09.   It was brought to our attention mid season that

there was a possible lubrication issue with the rear end pinion bearing. Woodings had

drilled a small hole, in the housing casting, down to the pinion bearing from the top of the

casting. The hole appears to be a passage through which oil, thrown up by the crown

gear, can get to, and lubricate the two pinion bearings. Since the normal oil level in the

rear end is below all bearings, all bearings depend on this "throwing" for lubrication. We

have compensated for this pinion lubrication deficiency by adding an extra quart of gear

oil to the rear end. This puts the bottom half on the pinion bearings in constant oil bath. It

also puts the axle bearings and axle completely in oil bath. We had anticipated that this

would result in lube oil seepage out of the 20+ year old seals, but to date has resulted

in little more than enough to allow dust to stick to the housing, no active drips. This

modification has had almost 600 miles this season with no other issues.