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Drain plug for 8.25" rearend, anyone?

Dragonslayer

NAXJA Forum User
Location
Los Angeles
I'm about to open up the rear cover on
my 8.25" corporate rearend to change
the oil and to check the ring gear lash.

While I'm there, I'm thinking of drilling and
tapping the bottom of the rearend center
housing to accept a small drain plug
(say, maybe 3/8" NPT) to make future oil
changes a simple and less messy operation.
Also, one would'nt have to buy a new cover
gasket during oil changes anymore, either.

The bottom of the casting on the 8.25"
rearend has a flat area that would seem
a perfect place for this mod.

This is for a street-driven car that'll
see no heavy off-road pounding (aside
from an occasional road pothole).

Has anyone done this?

Anybody see a downside of doing this?
 
I posted a thread on this some time back, the only issue is you will have to address is to fit a drain plug flush with the bottom of the diff, or risk breaking it off. Maybe an Allen type pipe plug? Also investigated a reusable cover gasket, I get tired of scraping silicone too. If you end up drilling it, be sure and open it up one last time to remove any metal you may have pushed into the housing while drilling and to smooth any burrs from tapping. Let us know how it works out...
 
Well, I did it.

After dilling, I found that the small flat area
at the bottom of the 8.25" Chrysler axle is
about 3/8" thick.

I opted instead to use a smaller 1/4" NPT
recessed allen hex pipe plug (instead of 3/8" NPT
in my earlier post) in order to reduce inducing
stress in this area and possibly start a crack
in the axle gear housing. I also stayed away
from drilling too close to the bottom center
cover bolt hole for this reason, too.

I wrapped the plug in teflon tape and screwed
it on using a simple "L" allen wrench (not a big
socket wrench) and moderately strong hand
torque.

So far, so good.
 
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