Rear Differential Leak

[CFranks]

Hello all. I noticed some gear oil pooling on the bottom of my differential and splattered a bit around the chassis (8.8 solid axle). Upon inspection I think I may be getting off easy, it appears to be leaking from the top fill hole of the Drake cover (see photo). The rear-end was installed by the initial builder (I bought as unfinished kit) so I don’t fully know it’s history. My understanding is the oil should be filled to the factory hole on pumpkin side, not the fill hole on the cover. Upon removing both fill holes, I stick my finger in and as down as possible and I don’t feel any fluid, so I believe I need to top it up. I have a few questions for the pros:

1. Does this make sense that this would be happening? I have the factory supplied stock vent bolt on the axle so pressure should be relieved. Is it as simple as the plug on the cover just wasn't sealed well enough?
2. Is there a recommended sealer I can use on the plugs when I put the fill hole plugs back in to better seal?
3. Since the factory fill hole is dry when I stick my finger in, I assume I need to top it up until it starts to come out of the factory hole? I believe he used Royal Purple 75w-90.

https://live.staticflickr.com/65535/50393017343_128d46f238_k.jpg (https://flic.kr/p/2jM4ooB)

Thanks!
Craig

[Papa]

I'd recommend a bit of this type of thread sealer:

https://www.amazon.com/gp/product/B000HBNTGY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[Railroad]

The fill level plug is usually in the same plane as the bottom of the axle tubes.

[Papa]

The fill level plug is usually in the same plane as the bottom of the axle tubes.

This is a good point. If you filled to the level of the leaking plug, you are probably way over-filled. There should be a fill plug on the cast portion of the pumpkin on the passenger side near the pinion.

[CFranks]

This is a good point. If you filled to the level of the leaking plug, you are probably way over-filled. There should be a fill plug on the cast portion of the pumpkin on the passenger side near the pinion.

Correct, the fluid is actually even below the factory plug on the pumpkin that you mention (which on mine is on the driver side of the cast pumpkin). Nowhere near the level of the leaking plug on the cover. So I'm actually underfilled most likely due to the leaking.

[TMartinLVNV]

This is Terry's ultra cheap trick for determining the fluid level. You get what you pay for :rolleyes: I use this on my Jeep a lot since I have aftermarket diff covers that change the fluid capacity and the fill plug is not in the right place. Having the fluid level at the lower portion of the axle tube is spot on.

Get a white zip tie. Bend it at 90 degrees at about 6 inches from the end. Insert it at the fill plug hole and run the bent end straight down until the 90 bend is sitting on the shoulder of the threads. Remove zip tie, hold it at the shoulder of the threads and presto! You can see your fluid level.

Make sure that you get a calibrated zip tie though. I've found that Harbor Freight zip ties to be spotty on calibration :o

[CFranks]

This is Terry's ultra cheap trick for determining the fluid level. You get what you pay for :rolleyes: I use this on my Jeep a lot since I have aftermarket diff covers that change the fluid capacity and the fill plug is not in the right place. Having the fluid level at the lower portion of the axle tube is spot on.

Get a white zip tie. Bend it at 90 degrees at about 6 inches from the end. Insert it at the fill plug hole and run the bent end straight down until the 90 bend is sitting on the shoulder of the threads. Remove zip tie, hold it at the shoulder of the threads and presto! You can see your fluid level.

Make sure that you get a calibrated zip tie though. I've found that Harbor Freight zip ties to be spotty on calibration :o

I heard that Harbor Freight zip ties were recently recalled due to false readings!

Good tip, I like this.

[cob427sc]

They're not mis-calibrated, they are labled in metric!

[Jay-rod427]

Tig welding wires never need calibrated. Jus sayin. LOL

[BRRT]

Do most experts call this a dipstick? :-)

First post! Hello everyone!

[Vegasjack]

Great idea, but do you bend the zip ties to the right or left?