8 3/4 diff refill

[am3rican]

I was tooling around on my roadrunner and took a picture of the rear diff. It looks like an 8 3/4. I'm used to seeing a drain and fill plug on the back of the housing. I'm not see it on mine. How do I drain and fill this thing?

 

[idrivemopar]

There is a plug on the passenger side of the diff housing, square type head, you will have to use a suction device to get the old gear oil out, then fill to just below that opening. Only other option is to separate the diff from the axle housing, which I don't recommend, as its a lot of work and you have to pull the axle shafts to do.

Hope this helps.

 

[1970GTX]

or........
http://www.moparmusclemagazine.com/...ing_a_drain_plug_in_the_differential_housing/

 

[eagleone1983]

I did what 1970GTX recommends and worked out great. You don't have to worry about shavings getting in your housing cause once you drill through the oil will pull the shavings with it as it drains.

 

[tallhair]

I did what 1970GTX recommends and worked out great. You don't have to worry about shavings getting in your housing cause once you drill through the oil will pull the shavings with it as it drains.

I've seen that before anyone have any issues with that mod?

How long / how many miles since you did it eagleone?

 

[Plucked Chicken]

Used the Harbor Freight sucker to do it this last Summer - Sucked out a lot of oil and worked surprisingly easy. And for as seldom as a rear-end needs draining..... just saying....

http://www.harborfreight.com/oil-suction-gun-95468.html

But that drain plug idea is "genius" as my Son would say. You most def would want to use a flush allen plug screw if you go that route, so it will not be damaged with a floor jack.

:thinker:

 

[tallhair]

Used the Harbor Freight sucker to do it this last Summer - Sucked out a lot of oil and worked surprisingly easy. And for as seldom as a rear-end needs draining..... just saying....

http://www.harborfreight.com/oil-suction-gun-95468.html

But that drain plug idea is "genius" as my Son would say. You most def would want to use a flush allen plug screw if you go that route, so it will not be damaged with a floor jack.

:thinker:

That's what I was thinking when I read it the first time! Looks like the one in the article sticks out and would be wacked or shoved in or damage threads by jacking up from the center section. I'd still be interested to hear feedback and would probably do it with the flush mount allen head plug.

 

[bigblock]

Just take out one axle and turn the car over on that side.

 

[am3rican]

I'll have the mechanic tap the differential when he has it up on the lift.

 

[tallhair]

Just take out one axle and turn the car over on that side.

That is so obvious now that you just typed that out bigblock Nice tip but you would have to jack up that one side pretty high to drain it almost completely right?

 

[D575]

That is so obvious now that you just typed that out bigblock Nice tip but you would have to jack up that one side pretty high to drain it almost completely right?

That stuff is pretty thick, I would think you would have to leave the car on it's side overnight.

 

[Cranky]

Just be careful if you drill out the bottom. The metal in that area isn't exactly real thick so there's not going to be a lot of threads and the risk is there for over tightening and stripping it out.

 

[am3rican]

Just take out one axle and turn the car over on that side.

Help! I was jacking the car up to get it on its side. Now I can't flip it back over

 

[A383Wing]

Just be careful if you drill out the bottom. The metal in that area isn't exactly real thick so there's not going to be a lot of threads and the risk is there for over tightening and stripping it out.

yea..what he said above...personally, I would not drill out the housing...suck out the fluid & refill it...done deal

 

[tallhair]

Just be careful if you drill out the bottom. The metal in that area isn't exactly real thick so there's not going to be a lot of threads and the risk is there for over tightening and stripping it out.

Also had that thought too Cranky. What it you build it up little off center then drill through that and use the flush plug?

 

[am3rican]

What's the drain interval on the differential

 

[Cranky]

What's the drain interval on the differential

Most never did change it lol. It's not like it's exposed to combustion by products etc but after a lot of miles, you will see some wear and you will get very fine dust like metallic particles that usually settle to the bottom of the housing. There is a way to do a possible cheat on draining it. Loosen all the nuts around the chunk and then jack up the nose (don't jack on the yoke) a tiny bit. Chances are, doing this will break the gasket which is thin paper but, you might be able to get it to seal again once you tighten it back up. Another thing you can do is break clean the gasket area and inject a small bit of RTV all around it but you have to get all of the oil to finish draining or the RTV won't work. There's enough play in the axles to do this but I like to pull the drums off before doing it that way. Like I said, this is the cheat way.....or the 'deep east Texas' way lol...but in deep east Texas, it would most likely not be changed.

 

[Plucked Chicken]

Another way some oil will drain is when replacing the pinion seal.

Just pulled the cover on a '73 half ton Chev 12 bolt rear - yes there was sludge in the bottom - but well below the gears. Still was nice to be able to clean it out.

I know my 2007 Chev 2500 manual has no maintenance schedule for the front or rear differential. Even though they have magnetic drain plugs. And the recommended taking it easy, no towing and varying speed for 500 miles when new, is more about the rear-end gears wearing in, than the engine these days.

 

[eagleone1983]

I've seen that before anyone have any issues with that mod?

How long / how many miles since you did it eagleone?

Fluids been in the diff almost a year and I've got maybe 400 miles on it. As stated I was real careful tapping and didn't over tighten the pipe plug. No leaks, no problems

 

[D575]

Tig in a Bung, thread problem solved.