Differential axial check plug

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Differential axial check plug

September 14, 2012, 10:07:58 PM

Well, that's what my manual calls it. Ok, I don't have one on my car. The closest I can see is a plug about half way up the rear of the housing. It seems a little low for checking fluid. So, how do I fill this one without taking the axle out and tipping on its side? Thanks!

Differential axial check plug

Reply #1 – September 14, 2012, 10:27:51 PM

Are you changing, checking or topping off the diff lube?

If changing, you all of the bolts out, but leave a few in the top to prevent the cover from falling off uncontrolably when you crack the seal. Prying yhe cover way from the diff body in this manner keeps the mess made to a minimum.

If checking, you remove the plug and using your index finger, stick it into the hole. The gear lube level should be at or just below the hole.

If filling, place a hose onto the "tip" of the gear lube bottle. Stick the other end of the hose into the fill/check plug and invert the gear lube bottle. Squeeze the bottle forcing the gear lube through the tube and into the diff. You will use more than one bottle of the correct gear lube. Exactly how much will greatly depend on your diff, whether it has a cooler or an extra capacity diff cover.

I hope that this helps.

Differential axial check plug

Reply #2 – September 14, 2012, 11:10:14 PM

Differential cover is off, the fluid is gone and I cleaned the gears with brake cleaner as suggested. My housing has NO check plug, other wise what you suggested would be great. Thanks!

Differential axial check plug

Reply #3 – September 15, 2012, 12:14:23 AM

I am ging by what you said, specifically:

Quote from: 86cougar;398226

The closest I can see is a plug about half way up the rear of the housing.

However, perhaps to avoid further confusion, perhaps you could post a pic or two of what you are seeing. The diff check plug is usually just at or below the axel centerline, so the diff is never actually "full" to the top.

Differential axial check plug

Reply #4 – September 15, 2012, 02:59:23 PM

I tried putting up pics, and I tried looking for a "how to" but I need to get my friend over here to show me how. It's the only plug I see, must be it. The manual threw me off, it shows it close to the top. Thanks!

Differential axial check plug

Reply #5 – September 15, 2012, 04:18:22 PM

The 7.5 and 8.8 absolutely have a fill plug. And to my knowledge so does every final drive i would think. If for some reason you cant find the plug and or if it wont come out. You can buy a rear cover that has one. I install a plug some times in covers to increase the oil capacity. Chevy's with floaters need more fluid as they tend to starve the bearings of oil. I now install a plug extender that is a 90* street EEL to accomplish more of a fill on those axles. Fill the diff till the fluid just starts to run out the fill plug on a level surface. Or on the lift!!

Differential axial check plug

Reply #6 – September 16, 2012, 07:44:36 PM

The "check" and "fill" plug..... are the same thing.

Differential axial check plug

Reply #7 – September 16, 2012, 11:15:44 PM

Thanks i know!!!! Took me 3 seconds to figure that out. But never heard it called a check plug??? LIVE AND LEARN!!!!!

Differential axial check plug

Reply #8 – September 17, 2012, 10:40:29 PM

HA!
here is what i do
shove an extension in the plug and undo with a wratchet
find a 6' long hose and transistion one end into the diff opening
now i get to stand up and dump oil into the hose
when the diff will not take anymore i slide a drip pan under the diff
remove hose
wait till the excess drools out
replace plug.

I have this tractor hydraulic fluid in a 5gal bucket and it says 85w140 or something like that.
thick as hell, thats what ive been working on for a few years now when i need rear gear oil since i dont have my tractor anymore. I figured its good nuff for a busy rear gear for my climate.

Differential axial check plug

Reply #9 – September 21, 2012, 12:23:24 PM

Done! Now I can check this off my list.

Differential axial check plug

Reply #10 – September 22, 2012, 12:45:49 AM

I have a small hand fluid "pump". Looks like a round ballon with hoses coming out of it. You can get them at harbor freight for about $5 bucks. I use them for everything. Siphening gas out of tanks, rear end fluid, refueling model airplanes, ect. It has a small check valve in the balloon, and it will siphion once flow is established.

Differential axial check plug

Reply #11 – September 22, 2012, 04:24:09 PM

Quote from: Haystack;398826

I have a small hand fluid "pump". Looks like a round ballon with hoses coming out of it. You can get them at harbor freight for about $5 bucks. I use them for everything. Siphening gas out of tanks, rear end fluid, refueling model airplanes, ect. It has a small check valve in the balloon, and it will siphion once flow is established.

yeah, ive been needing to c00ch up a couple of those, glad to see some feedback on them.
really needed one a month ago when my son put to much trans fluid in. i was thinking the small ones you put on a drill might be better to have for things like this.

Differential axial check plug

Reply #12 – September 22, 2012, 05:35:15 PM

Well, I've done more to my car than I have ever dreamed of in the last 3 months than I have done the whole 7 years that I've owned it. Having a head full of knowledge that I get from you guy's helps, but... it seems the first time I tangle with something new, well nothing like "on the job training"! I'm glad I put a pan under the differential my first shot at it. All I did was put a transparent hose on the nose of the bottle, fit the bottle right up in the well and squeezed. Just make sure you hold that hose in place or you'll be looking like me when I crawled out (lol).