Toyota Tundra Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
222 Posts
Discussion Starter #1
First, how does my oil look? Is that what it supposed to look like, or is there an indication of anything be wrong?

Second, when I loosened the fill cap it hissed like a beer can opening. Is that normal? I thought there was a breather to keep pressure from building up?

Third, anyone know off hand what the torque specs are for the two plugs? Or is it in the manual?
 

Attachments

·
Moderator
Joined
·
7,925 Posts
Should not be any pressure. Have you done the breather modification? I recommend it very highly. Cheap and easy to do and have not had a single seal failure since.

Here is a picture of my first differential change after purchasing the truck used.
 

Attachments

·
Moderator
2015 Toyota Tundra DC SR5 5.7L
Joined
·
8,537 Posts
First, how does my oil look? Is that what it supposed to look like, or is there an indication of anything be wrong?

Second, when I loosened the fill cap it hissed like a beer can opening. Is that normal? I thought there was a breather to keep pressure from building up?

Third, anyone know off hand what the torque specs are for the two plugs? Or is it in the manual?
Based on what can be seen in the pic, the diff oil looks fine. How many miles on it?

If you had pressurization that manifested itself by hissing when removing one of the plugs, then your breather is clogged. You must remove/clean/replace the assembly immediately. Too much pressure (caused by heat) will stress your axle seals and may blow through and leak.

Torque specs are 39 ft/lbs for both plugs.
 

·
Registered
Joined
·
222 Posts
Discussion Starter #4
Damn. What are the chances of the dealership having the breather assembly in stock so I can just swap them out?

62k and change and the first diff oil change on this truck.
 

·
Moderator
Joined
·
7,925 Posts
Damn. What are the chances of the dealership having the breather assembly in stock so I can just swap them out?

62k and change and the first diff oil change on this truck.
Do the breather mod - has to be less expensive than buying an OEM breather from the dealer. Much better to have the breather run through a tube up behind the taillight lens as it keeps it from getting clogged.
 

·
Registered
Joined
·
3,058 Posts
Are you sure the hiss was from built up psi? The first time I removed the fill plug on my diff, I heard a hissing noise. I removed the breather and it was OK. After some further research on here, I found the hiss I heard was actually air being sucked into the diff rather than blowing out. The cooling diff lube had created a vacuum and the breather has a one-way check valve to relieve psi with no way to compensate for the vacuum. The neg. psi was equalized when the diff plug was removed, causing the hiss.
 

·
Registered
Joined
·
222 Posts
Discussion Starter #7
I suppose it could have been a vacuum... what would be the easiest way to figure out which way the air was moving?
 

·
Moderator
2015 Toyota Tundra DC SR5 5.7L
Joined
·
8,537 Posts
I suppose it could have been a vacuum... what would be the easiest way to figure out which way the air was moving?
Drive it around and get the diff nice and hot. Then, jack the rear up slightly, tape a small strip of paper so it hangs over the fill plug, and remove the plug slowly. Watch the paper. If it's heat pressurization, the paper strip will blow out.

Does anyone know the max acceptable pressure for the axle seals? The valving pressure in the breather?
 

·
Premium Member
Joined
·
533 Posts
Are you sure the hiss was from built up psi? The first time I removed the fill plug on my diff, I heard a hissing noise. I removed the breather and it was OK. After some further research on here, I found the hiss I heard was actually air being sucked into the diff rather than blowing out. The cooling diff lube had created a vacuum and the breather has a one-way check valve to relieve psi with no way to compensate for the vacuum. The neg. psi was equalized when the diff plug was removed, causing the hiss.
Maybe he had a snake in there...:)
 

·
Registered
Joined
·
3,058 Posts
Does anyone know the max acceptable pressure for the axle seals? The valving pressure in the breather?
IIRC, the breather just has a steel ball in it (like a BB) with no spring. The pressure required to unseat it would be minimal while any outside pressure - water, etc. - would push it down and seal the diff. Not sure about the axle seal psi.
 
1 - 10 of 10 Posts
Top