Front diff fluid question (1 Viewer)

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Thanks for all the advice guys. It’s supposed to be 103 this weekend so I think I am just gonna rinse and repeat a few times with gear oil over the next couple hundred miles. I have had no problems with the diff or birfs I just knew the seals were bad as there was tons of grease leaking from the wipers. I was thinking of putting in a can of sea foam with some oil and doing an initial fill and rinse with just like 5 or 10 miles of driving to warm it up but I didn’t know if it was safe to put the sea foam in there as I doubt I would be able to get ALL of it out after draining. Going to finish the job this weekend as long as the heat doesn’t take me first.

Thanks again
seafoam will break up the sludge. youre going to have to fill with fresh gear oil anyway and flush the crap out a couple times. seafoam wont hurt it. infact if you ever get water in there seafoam is your best friend...
 
seafoam will break up the sludge. youre going to have to fill with fresh gear oil anyway and flush the crap out a couple times. seafoam wont hurt it. infact if you ever get water in there seafoam is your best friend...
That's debatable.
 
Seafoam is evil.

It is another Snake Oil product.

I'll bet if you rub it on your junk, your wife will have better Oh's.....
 
All the time wasted by filling and draining you could pull the diff, inspect the gears and reinstall.

If it's a locked diff make sure you lock it or it won't come out. Also mark the driveshaft orientation.

Fipg will work best to seal the diff with no paper, just make sure it's clean with no oil residue.

The small nuts are only like 28ft lbs. Confirm that in the fsm.

The best thing to do to get all the grease out quickly is pull the diff and get some rags to push through the axle tube.
 
Kind of resurrecting an old thread here….but…. I’ve just rebuilt my front knuckles, pulled the axel shafts etc. Same routine of bad seals and moly colored diff fluid. Nothing new, really. But my question is that when I drained my diff (it had been refilled by a shop a couple months ago) I drained out almost a full gallon of fluid…. How is that even possible ? I opened the fill plug first, and nothing came gushing out… and I did let it continue to drain as I lifted one side and then the other over several hours. The axel seals were still intact (not totally gone etc.). The full gallon is just a bit puzzling 🤔 ….. any thoughts
 
Kind of resurrecting an old thread here….but…. I’ve just rebuilt my front knuckles, pulled the axel shafts etc. Same routine of bad seals and moly colored diff fluid. Nothing new, really. But my question is that when I drained my diff (it had been refilled by a shop a couple months ago) I drained out almost a full gallon of fluid…. How is that even possible ? I opened the fill plug first, and nothing came gushing out… and I did let it continue to drain as I lifted one side and then the other over several hours. The axel seals were still intact (not totally gone etc.). The full gallon is just a bit puzzling 🤔 ….. any thoughts

It's easy to overfill the diff housing.
Just keep pumping oil in. It's thick enough that it won't gush out past a fill hose, and if you put the plug in quickly, you can easily get a bunch of extra oil in there without spilliing more than a spoonfull or two.

Too much oil increases drag, and maybe increases heat inside the housing due to additional friction. It would take quite a bit of drive time to build up a lot of heat.
 
"I rebuilt my front knuckles-----drained out almost a full gallon of fluid---"

@Howl : The capacity of the 80 Series Front diff is close to 3 US quarts (2.8 locked, 2.9 non-locked), then add the volume of grease that got sucked in.

Important to remove the breather hose pipe assembly that's screwed into the left top of the axle housing, clean it out (it tends to get plugged with grease) then bypass the factory breather with an oil resistant hose running from the pipe nipple on the axle housing up to the engine compartment, zip tie it off somewhere and stuff a small filter or breather into the open end of the hose.

Fixed it
 
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"I rebuilt my front knuckles-----drained out almost a full gallon of fluid---"

@Howl : The capacity of the 80 Series Front diff is close to 3 US gallons (2.8 locked, 2.9 non-locked), then add the volume of grease that got sucked in.
That is quarts not gallons. 2.8 or 2.9 quarts.
 
I don't know about you guys but I definitely can stuff 3 gallons of gear oil into my front axle housing, it's a technique
I learned while living deep in the Congo (jungle) to prevent water from getting into the axle while fording rivers.
Surprised you guys didn't know that???

You just have to tilt the entire axle (or vehicle) 90 degrees and pour the gear oil in via the spindle tube facing up (plug the other end first of course)
then plug the up side when the axle housing is full and drop it back down horizontally. You have to work fast however when reassembling the knuckles, axle shafts and Birfields, etc or it will all spill out, then you have to start over.

The process is obvious.



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jk


Yeah, somone typed gallons instead of quarts :oops:
 
"I rebuilt my front knuckles-----drained out almost a full gallon of fluid---"

@Howl : The capacity of the 80 Series Front diff is close to 3 US quarts (2.8 locked, 2.9 non-locked), then add the volume of grease that got sucked in.

Important to remove the breather hose pipe assembly that's screwed into the left top of the axle housing, clean it out (it tends to get plugged with grease) then bypass the factory breather with an oil resistant hose running from the pipe nipple on the axle housing up to the engine compartment, zip tie it off somewhere and stuff a small filter or breather into the open end of the hose.
I appreciate the lead on extending the breather, Thanks. I know I posted this on the 80 series board, it was the thread that seemed most appropriate 🤷🏼‍♂️. The truth is, I drive a ‘76 FJ40… Diff capacity 2.6 qts… still real close to the 2.8 of the 80 series. Based on the color of the fluid drained, it mixed with a bunch of moly grease!
 
Decades ago with my first Land Cruiser (FJ60) I thought more gear oil would be better than less so drove it up on a set of metal ramps in order to tilt the axle housing upward to get more gear oil inside before installing the fill plug. I quickly learned that was not a good idea when gear oil started to blow out of the axle housing breather after a drive at highway speed. So I suppose if someone tried (like I did) they could stuff another gallon quart into the diff.
 
I don't know about you guys but I definitely can stuff 3 gallons of gear oil into my front axle housing, it's a technique
I learned while living deep in the Congo (jungle) to prevent water from getting into the axle while fording rivers.
Surprised you guys didn't know that???

You just have to tilt the entire axle (or vehicle) 90 degrees and pour the gear oil in via the spindle tube facing up (plug the other end first of course)
then plug the up side when the axle housing is full and drop it back down horizontally. You have to work fast however when reassembling the knuckles, axle shafts and Birfields, etc or it will all spill out, then you have to start over.

The process is obvious.



---------------------------------------------------------------------








jk


Yeah, somone typed gallons instead of quarts :oops:

True story, I had a Lada Niva for a while. To check or fill the gearbox, you had to raise the wheels on one side 125mm.
The fill plug was below the oil level.
 

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