So I had a bit of a history with my passenger side cv axle coming out. If interested please see my post history.
(https://www.clublexus.com/forums/is-...f-oil-pan.html)
(https://www.clublexus.com/forums/is-...-anything.html)

But the question at hand is the Diff seal didn't get changed because its a huge pain in the *** to get to (as the diff needs to be taken out and that means dropping the sub frame i'm pretty sure??). Also because the cv shaft probably wasn't able to come out enough to rip the seal.

That said i have been watching for leaks religiously. i have seen nothing on the ground... but i still see some wetness from diff oil at the bottom where the passenger side axle shaft bearing sits in the diff tunnel of the oil pan. I have cleaned it a few times but i will look a few days later and its wet again. This made me think the seal is leaking even though i never see anything on the ground. Or maybe its still just whats left over from when the cv shaft originally came out and poured all the Diff fluid out... I don't really know. but i have been driving it for a month and i figured i would just check the Diff and see how much fluid is left after driving it for as long as i have.



So on the weekend i opened up the fill port of the front diff (using a 14mm offset box wrench for anyone looking to do this). as soon as the bolt was out a small stream off fluid started coming out. it wasn't pouring out like crazy but a small steady trail of fluid started coming out. To me this means its full and is a good sign that nothing is really leaking.

Now the only question is, i had to drive the car for a bit to heat up the Diff to get the bolt out (it was stiffer then i would like for a bolt that i can not risk stripping). So is 5 mins sitting enough for the diff fluid to settle or could i have been making a bad assumption that the diff is full of fluid?

 

How long did you drive it and was the diff hot to touch?
If not hot >120F or so, I'd say you're fine.

Maybe drop links to your other threads here??

 

5 mins. it was warm but did not burn me.

I'm curious of your thought processes (if you don't mind me asking) if it was 120F+? how does that change things? just the expansion of fluid or something else i am not thinking of?

 

I think this what 2013Fsport is referring too. Read here:
https://www.randysworldwide.com/blog...uring-break-in

If you take measurements with an IR gun you need to do it immediately after engine shutoff. Since the front differential is close to the engine. It's going to heat soak like crazy.

On another note if I'm not mistaken. The front differential on the 250. The fluid capacity is around .74 qts. Have you inquired about the seal replacement? Im curious to know if it's a must to drop the differential.

 

break in temps aren't related to checking the fluid level (as far as i know...) so i'm still curious what 2013Fsport alluding to.

In terms of changing the seal, I don't see any other way to get the diff off to get to the seal. If someone has a way to do it with out taking the diff off please please let me know!

 

IS350 @100,000 miles ~ 100°F
IS350 w/new bearings & LSD 160°F
Tundra front and rear ~ 90° / 120°
Tundra t-case ~ 170 - 200°F

All numbers above are after 30 min hwy use. 5 minutes will be ambient temp. Engine oil takes 10 to 15 min to reach 165°F and even exhaust manifolds inches away have little impact on a diff in 15 min.

But, yes, fluids expand with heat, so things like differentials are checked at ambient temp. I just wanted to confirm...

 

Well I clearly wasn't paying attention. I thought about differential operating Temps.

As fir the differential heat expansion fluid check yeah. As with 2013Fsport said should be done at ambient temp.

Anyhow I did find this link again. It does state the diff has to come out depending on the side.

https://carspecmn.com/is250-is350-gs...l-replacement/

 

This is a good reference though break in or DD w 100k on them. Obviously it depends on the oil quality and I would apply that to most fluids as a guide. They need to get above 100+ 160F to remove moisture, then take note of excursions north of 250F for advanced maintenance for those of us who care that much...