Rear Diff /3rd member

[Davis]

I have a 73' bronco with a 9" rear. there is not a fill plug on it??? Is there any way to change the gear oil without removing the rear end completly?

 

[TX '73]

I have a 73' bronco with a 9" rear. there is not a fill plug on it??? Is there any way to change the gear oil without removing the rear end completly?

The fill plug should be on the left side of the pumpkin just below and in front of the axle tube if I remember correctly. If you really don't have one, thats a mystery. You might think it should be on the top of the pumpkin but its actually toward the bottom for draining. Hope this helps.

 

[89Bronco58]

get under the truck, with your back to the front of the truck, look straight at the rear, it will be on the right side of the driveshaft/pinion, twards the top, but on the part of the rear that is sideways and flat, use a 3/8 socket and 3 inch extension to remove the plug, fill, and retighten plug, this picture shows you right where the plug is...

 

[Davis]

Thanks for the help. There is a spot where you are refering too, however there is not a plug. I have never seen one without that is why I'm asking???? There is a vent on top on the driver side, you know where they brake lines split. Will oil reach the gears from there or is it on the other side of the seal? There is a drain plug on the axle housing.

 

[S_bolt19]

All 9" axles have them there. Yours is either gummed up with grease or someone put a plug in it that can't be removed. That is where you have to fill the diff up at. The line you are talking about at the break line is a vent tube that goes up into the frame. All that does is let the axle housing breath. I have seen seals on both sides of that line, so I wouldn't even try to fill up your gear oil from there. As for the drain plug, I don't know what you are talking about. I have never seen a drain plug on a 9" that wasn't owner fabricated. The absolute best thing you can do is take pictures of where the fill/drain plug SHOULD be and a picture of this drain plug on the axle housing. Are you saying there is a plug on the axle tube or on the carrier housing? Post some pictures because that will help everyone understand exactly what you are talking about and in turn be able to give you proper advice.

 

[STLKIKN]

Some of the early Broncos came with the carrier from the car line-up. Those carriers did not have a fill plug on the carrier, instead it was located in the back of the housing itself. ( have seen this up to 68 model year) If you are one of the unlucky ones that has purchased someone elses "oops" (puttting the early carrier into a later housing) you may have to fill it through the vent tube fitting.

If the housing does have a drain plug in it, then someone must have put a fill plug into it too... ( you would assume they would have one anyways??)

 

[89Bronco58]

well it looks like your only choice is to fill from the vent tube, but make sure you find out how many quarts a 9 inch holds exactly so you dont overfill it, i believe mine is a little less than 4 quarts

 

[jstevenson509]

I'm looking for the exact # of quarts it'll take to fill my 79's 9".

Can't find it anywhere.. I know I know I should have a chilton's by now.

Worst case scenario I'll put in 3 qts which is a good round number according to Napa.. Thanks!

 

[Bully Bob]

I have a 73' bronco with a 9" rear. there is not a fill plug on it??? Is there any way to change the gear oil without removing the rear end completly?

I think I'd loosen the 10 bolts..., drain..., tighten bolts.

then jack one axle tube higher.., pull the axle, & fill down the axle tube.

(not something you have to do very often)

Axle takes only minutes to pull.....

B

BTW..FYI

66-68-----@ 5---pts.

69------------6.5 "

70-71/73-77 9---"

72------------6---"

78 on--------6.5-"