anybody ever put a drain plug in their 8.75 housing

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moparmat2000

moparmat2000

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title says it all, anybody put a drain plug in their 8.75 axle housing?

i used to have a 60 chevy el camino (like an impala) it had a GM corporate rear similar to the 8.75 mopar one (hotchkiss style) it had a drain plug in the very bottom. anybody ever modify theirs?

im thinking grind down the weld on the inside of the bottom of the axle housing center, weld an 1/8" or thicker steel plate maybe 2" x 2" to the inside of the housing where both halves meet, overlapping both sides to strengthen the axle so it can be drilled. then drill and tap dead center at the bottom for a pipe thread, im thinking of using an internal hex key plug with a little thread tape so it fits flush and doesnt leak. this shouldent protrude into the gearcase, shouldent have a problem with clearance.

my 60 chevy had a plug with a plastic washer at the very bottom, looked a bit like an oil pan plug. this was extremely handy when changing out chunks doing gear swaps. not sure if it was a factory thing or a previous owner did it.

i did this with a drain plug idea to an 88 dodge daytona shelby Z too. it had a 5 speed, and chryco's solution was remove drivers side axle to drain it.

any ideas? thoughts? eureka moments like why didnt i think of that LOL

matt
 
Sounds good, go for it .

The lack of a drain plug on my B100's 8 3/4 has kept the original fluid in the poor thing since 1974 and 280,000+ miles.
Oh sure not ALL the original fluid is still in it, as axle bearings and seals have been replaced a couple of times :)
 
Doing it tomorrow......at least I was until reading your post. Do you think drilling will compromise the strength enough to merit the 1/8 plate? I am putting in 1/8 pipe plug.
 
I did mine just like they showed in mopar muscle. I think I went 1/8" npt but don't tap too far in as pipe threads are tappered to help seal.
 
My driveline shop did one up for me. I believe they drilled a larger hole then welded a bung underneath with a plug. But to protect the plug from damage when you jack the car up, they also welded a short piece of thick pipe around it for the jack saddle to contact.

I also had them weld a filler cap at the top of the smooth face for filling and gear inspection. (Car doesn't have the OEM gas tank to get in the way.)
 
i did one in my 73 D100. used a 1/2 inch drain plug with a nut welded on the inside of the housing, and i cut 2 reliefs in the side of the nut itself so the gear lube would drain completely, used a nylon washer with it, worked very well and i didnt have to worry about breaking it off being 1/2 inch.
 
My son just did his with a 1/2 npt bung and the pipe for protection like Locomotion said. Real nice and safe to hold the jack in place if you move the car.
 
i was thinking about the reinforcing plate for 2 reasons.

1. if i grind on the welds on the bottom of the housing to make it smooth for the drain plug on both sides, it may weaken the housing. dunno if thats true or not, but i'd rather not chance it.

2. if i use a flush inside hex key plug with pipe threads, i will need enough thickness in material for threads for the plug. plus i want the plug to sit pretty close to flush with the bottom of the housing when its installed

i like some of the other ideas like using the welded in nut with the reliefs cut into it for draining, and then maybe using an engine oil pan drain plug with nylon washer. this is why i was asking the question. theres many more ways than what i thought up to do this. i'm liking the other ways to do this.

hope this helps anybody else thats wondering about the plate idea. if i proceed with it, i will post a thread along with pix of progress, and end results.

thanks for all your ideas on this one. i came up with wanting to do this after a bit of a messy afternoon. i actually used a 3 foot wide roll of butcher paper under the rear end while it was on a set of stands. and a big drain pan under it. kept the mess to a minimum this time. i was like Hmmm my 60 chevy had a drain, why not a mopar

matt
 
just read the link to the mopar magazine article about installing the drain plug, its offset to the passenger side and not in the center of the housing. i may go this route, and just weld a small 1/8" thick circle of steel plate like a washer without a center hole on the inside offset to the passenger side will use an allen key type hex plug and thread it to make the plug sit flush. I will drill and tap where the 1/8" thick plate is so i got more than enough thickness for threads. I like to overdo things a bit sometimes.
 
Mine was done with the Allen head pipe plug it is offset to the passenger side for clearance of the gear and welds. It sits flush and the housing it fairly thick so I didn't bother welding to build it up. The housing is still apart and will be happy to post pics of the inside and out if you want.
 
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i have never done a 8.75 but have done a few ford 9" but i would weld a bung in to the back dome part so that if it got drug across any thing it would not get rippedd up but with a car that is a different story
 
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