Leaking New Front Diff

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ZRotheohv

ZRotheohv

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Nov 6, 2005
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71
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236
Location
Riverside, CA
I JUST got my truck back on the road after replacing the front differential, and installed the third with a dry gasket. Apparently that wasn't enough since it's dripping out of there (the bottom is wet and leaves a little half dollar sized puddle whenever I stop). I read about using FIPG instead of the paper gasket and wish I would have done that.

So, is there anything I can do to stop the leak? I was thinking about tightening the nuts down more, but I'd hate to strip out a stud. The FSM says the torque is 18 ft lbs, but what can I realistically put on it?

Is there any way I can move it a little bit to fit the FIPG nozzle in there (while still being connected to the axles)? It'll bother me until I get it fixed since it's not easy to check the level in there. Thanks!
 
18ft lbs over that many nuts is a LOT of force, and dealing with a stripped stud or hole in the housing is a LOT of work. You don't need more torque.

Basically, you need to take it apart again.

I've always put a very small bead of FIPG around the base of the studs, then used OEM gaskets with a very thin layer of FIPG.

Technically if the flanges are true you don't need the FIPG but it can help deal with any imperfections.
 
ZUK only uses FIPG, no gaskets. I think that's the way to go.
 
Just chalk it up to experience and remove the third member, then install it with grey permatex minus the paper gasket.
 
I thinly coat the oem paper gasket on both sides (completely covered with fipg) with grey permatex and throw in like that..never any leaks..
 
Nice bead of Permatex Ultra gray...no paper gasket
2016-03-30%2010.11.37_zpskwlfrunw.jpg
 
No one uses the Toyota orange FIPG? :popcorn:

Oil dripping off the bottom of the front diff can also come from the top side of the gasket or from the oil seal on the shaft. You positive it's the lower third gasket?
 
I'd coat the paper gasket both sides with some ultra black or the right stuff.

Make sure the flanges are super clean and flat. File any burrs. Use brake clean and a rag to clean off the flanges before assy.
 
maxamillion2345 said:
I'd coat the paper gasket both sides with some ultra black or the right stuff.

Make sure the flanges are super clean and flat. File any burrs. Use brake clean and a rag to clean off the flanges before assy.
Click to expand...

Not a good idea to coat any paper gasket with rtv. You can use the "spray on gasket sealer that is red and tacky". I would skip the gasket and use the sealant only.
 
maxamillion2345 said:
I beg to differ. But I'd like to know why you think so.
Click to expand...


Its one or the other! If its leaking with paper then the mating surfaces were probably not cleaned well or has pits. If you need to just hold it in place then the red n tacky spray will do that. The rtv and paper is an additional thickness that will be squished and squeezed out or into whatever you are sealing. This is particularly bad when it is pushed into an engine oil passage. I know, I know this is a differential but still! Its not a good practice. Also the rtv will dry hard and the paper gasket will absorb oil which causes it to expand. Hard rtv will not expand which causes a leak.

Good luck!
 
Can't believe nobody uses spray adhesive or Gaskacinch! I use some 3M spray adhesive on both sides of the gasket, and walk it on the studs to make sure there are no tears, and run the nuts down.
 
Ah that's what I was afraid of. I just pulled the VC out of the transfer case and used the orange FIPG on reinstallation and was pretty impressed with it. This was the second time in as many years that I did a complete front axle job and REALLY don't want to pull the axles a third time. I might just keep the diff topped up and put it on the back burner.

The entire diff is completely dry except for right under the bottom three bolts, so I'm just about willing to bet my life that it's the paper gasket. The pinion seal is new and professionally installed

So there's not even a couple millimeters of space you could move the 3rd without pulling axles?
 
I would drain the 3rd completely. Loosen all the 3rd member nuts and split the seal. Let everything drain for at least a day. Scrape everything as clean as you can get it. Then place a bead of your favorite FIPG ( I use ultra grey). Cinch it down and wait at least another 24 hours before filling it back up. I think you'll get enough space even with the axle shafts in to do the above method successfully. It's definitely worth a shot in my opinion.
 
I should add, I did this successfully with my cruiser once. Lasted several months until I broke my front ring gear and then I did it right. I've never used a paper gasket after that, only FIPG.
 
I'm 2 for 2 using OEM paper baskets. I have in the past had to redo other things that use paper gaskets due to missing a piece of old gasket causing leaks. I find with paper the surface has to be really clean. With FIPG it's a bit more forgiving.
 
ccslider said:
Its one or the other! If its leaking with paper then the mating surfaces were probably not cleaned well or has pits. If you need to just hold it in place then the red n tacky spray will do that. The rtv and paper is an additional thickness that will be squished and squeezed out or into whatever you are sealing. This is particularly bad when it is pushed into an engine oil passage. I know, I know this is a differential but still! Its not a good practice. Also the rtv will dry hard and the paper gasket will absorb oil which causes it to expand. Hard rtv will not expand which causes a leak.
Click to expand...

No more RTV will squeeze out on a paper gasket than if it's just RTV. Exact same amount of force applied to squeeze it out. "additional thickness" MIGHT be a thousandth or two? as in, significantly LESS than the OEM gasket. By that logic people should ALWAYS use the OE gasket so they don't take too much spacing out of the system and misalign the axles. For those paying attention, I'm not being serious. The extra thickness of the RTV is an absolute non-issue.

The "paper" gasket is actually a rubber impregnated fiber base.. no more oil will saturate it and leak out than if it were a FSM-specified "paper" gasket install.

There is NO legitimate reason NOT to properly apply RTV (very clean surfaces, etc) to the OE gasket if an owner wants to do so.

I agree on reasons it is leaking with paper gasket however.. surfaces either aren't parallel, flat, or clean.
 
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