Any of you guys out there ever drilled a hole in your diff cover so you could add a drain plug to your 9" rear? I'd really like an easier way to monitor my gear lube. So if you have please share details. I mean, where's the best place to drill the hole so it's not too low that everytime you go in to check fluid it doesn't all run out, and obviously not too high so you can actually monitor the fluid. Then on top of that, what kind of plug did you use (ie, diameter, length, thread count)? Thanks for any and all info.

I know my 79 bronk had one midway on the pig. But are you looking for somethign to put on the bottom so you can drain it?

Same with the TTB 44, no place to drain so you gotta pump it out. Many people drill into the bottom and put a pipe thread plug in there. Im going to do that next time i do a fluid change.

I've heard about it before i'd love to do it but i've heard if you didn't drill in the right place on the diff you could cause it to start cracking.

Now I may be stupid, but I swear, my 9" doesn't have a plug. I guess I don't want a drain plug, I want a plug like is on my D60's. So I can monitor fluid level and top her off if I need to. I just don't know where to drill the hole and what size hole and plug I need.

As far as the diff cover cracking...that's what the aftermarket is for..haha.

Yeah it doesnt look to me like the 9" has a drain plug... Kind of strange for a 3rd member axle... Do they expect you to pull the driveshaft and pull the 3rd member every time you want to change the fluid? How does that even work? But then if you did that, how do you keep the fluid in the shell while you're trying to reinstall the third member... Hmm... It HAS to have a fill plug.

Where's Tony when you need him!? He's got a 9" in his truck.

again just like the TTB dana 44 you gotta pump the fluid out.

95bronk said:

again just like the TTB dana 44 you gotta pump the fluid out.

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Well I was looking at pictures of 9"s and I couldnt spot a fill plug either... I figure that it HAS to be there, but I just couldn't see one.

95bronk said:

again just like the TTB dana 44 you gotta pump the fluid out.

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From the posts above, it seems that there may be no plug at all. If this is the case, which I don't see how, where would someone put the hose for the pump?

It has to have some way to add oil after the 3rd member is bolted in?



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460 said:

It has to have some way to add oil after the 3rd member is bolted in?



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My thoughts exactly. How come no one can find it? LOL

The third members themselves usually had the fill plug except some of the older ones. (war case) On older 9" (with war case) rears the plug was in the back of the axle housing. If someone installed an older third member in a newer housing it is possible not to have a fill plug. They would have filled it from the end of the housing before they slid the axle in. This page shows picture examples the different third members with plug location.. http://www.maliburacing.com/ford_9_inch/ford_nine_inch.htm

Whenever you're building an 8-inch rearend, be mindful of the oil-filler plug situation. From '62-'66, the oil-filler plug is in the axlehousing, which means there is no oil-filler plug in the carrier. Use a '62-'66 carrier in your '67-up axlehousing and there will be no way to check the axle for lube. This same rule applies to 9-inch axles as well. Make sure your carrier has an oil-filler plug if you're using a '67-up housing.

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Linky, then look in the side bar, it says for 9" rears also -> http://www.mustangandfords.com/tech...rential_builders_guide/8_inch_light_duty.html



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How the hell do you add fluid if there is no fill plug? my 9 has a fill plug.

The third member has a fill plug.
The housing does not.
I think it's on the drivers side by the yoke.

How could so many Ford guys not know this???






For a drain plug, I know several people that take the bottom stud out of the axle housing and tap it for a bolt, so when you want to drain the fluid, just take out the bottom bolt instead of takeing the axle shafts out and removing the third member.

When I change my fluid next time I'll have to remove the center section so I can get out all the metal shavings from the new gears.

MBBFord said:

How could so many Ford guys not know this???

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I umm.... knew it but uhhh.... I was testing the rest of you.... you all failed...

Lol yeah I didn't know cuz I've never actually been within close proximity of a 9". Only worked with my 8.8" and had a few looky loo's at my brother's 10.25"

Hey thanks matt...I really appreciate the info and tip for draining. I too have never had an experience with 9"...either 60's or 10.25's. I'm gonna get on my Bronco tonight if the snow stays away...and if I can find a parking spot in the lot rather than the street. Thanks again

FWIW, a guy i know with a 10.25 drilled a drain plug in his.

other than that tidbit, i'm no help

I called my uncle the other night and asked him about this and he said yeah its not hard at all you wan to put the plug at the lowest point on the housing, drill it tap it and your done..

Thanks Tex...I figured it was easy...I was just searching for pics or measurements to see if there would be any internal clearance issues.

MBBFord said:

The third member has a fill plug.
The housing does not.
I think it's on the drivers side by the yoke.

How could so many Ford guys not know this???

Click to expand...

Except, as stated earlier in the thread, the older 9" rears had the plug in the housing, and NOT in the third member as you said. An older third member in a newer housing will have no drain plug.

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I drilled a 3/8 hole on the bottom rear of the diff and bolted a short bolt in there with a nut, then welded the nut to the housing. Its not at the lowest point of the diff because I would rip if off, but most of it comes out. If I were to do it again I would step up to a 7/16 or maybe even 1/2 bolt, it takes an hour to drain the diff through the 3/8 hole, I park on a good incline when I do it so that I can get more out. It sure beats pulling the shafts and third member.