CV shaft Needle Bearing Issue? Sanity check me please

Oh, and...

I walked outside earlier today and there's a small puddle under my truck...guess where? Yup, left side of the diff. My bearing's gone and the seal is leaking. Apparently happened on Wed., that's the last time the truck was driven.

I've watched it for quite a while as I don't have any noise. The CV has had quite a bit of play. Never bothered to measure, but .050 wouldn't surprise me.

 

FWIW 2" lift on my offroad .. at approx 1,200 miles on the lift with 285-75-16's the needle bearing started talking. Thanks to TW I was already aware of this possibility. ECGS solved it and I am also running 75-90. 100,000 miles later and so far no problems. I also wheel a lot, so that cv gets used from long days in 4 high and low. Checked the wheel bearings today after tire rotation and everything is still tight. Has been a good truck so far. I am mostly in warmer SW climates, even the winters here are not too harsh in ref to the oil viscosity.

 

The front differential in a pro is different? What?! No way?!

 

I went around a dealership and felt the play in all the trucks. They all had it.

 

Yup. The whole assembly is a different part number, but the only actual different parts inside are the spider gears and the carrier they fit into. They still use the same needle bearing, and nobody ever hears of stock pros having needle bearing problems, or at least not more than anyone else, and they have all that CV angle to boot from the factory lift. The only logical difference since spider gears and carrier are different, is that they are actually a nicely machined fit part instead of being loose fitting like the ECGS video demonstrations of stock carriers. On the other models, the CV running true in the needle bearing is what actually stabilizes the side gear, which is dumb.

 

I drove on my "vibration and noise" for over a year.
Indeed the "problem" is in the eye of the beholder.
I did my bushing when I did my wheel bearings.

 

Damn, that’s a hidden reason to buy a pro I guess. Not just for the skewp.

 

Lol, not sure it’s a reason to buy the truck. However, it does prove how cheap Toyota is. Instead of just making diffs that solve the cyclical vibration for everyone, they keep giving everybody without a Pro the standard diff and then swap them under warranty TSB when complaints happen.

When I traded my 5.29 gears for 4.30s from a guy with a stock truck, his was a Pro so I kinda lucked out.

 

I never said other wise.
I don't give a shit what fluid anyone uses.

My point was, I haven't seen the issue happen nearly as much using

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90.
I still have 85w-140 in mine.

I let the shit leak out and called it good.
I added fluid 2x, and had it puke it out 2x.

I finally said, "fuck it". Let it choose the level it wanted to be.....

 

Just a thought on why 85W-140 may have breather problems. Could it be the thickness sticks to the opening in the diff and the capillary action, or surface tension causes it to adhere to the tubing and over a period of time exits the other end with the pressure within the diff. When I do my diff work gearing and ARBs I plan to move to Dino 85W-140 in both ends. I'm thinking of the possibility of increasing the size of the vent tubes at that point so venting oil could be lessened.

Aisin used to (1980s) put a shield around the diff vent inside to decrease this likelihood, or is so my belief, anybody know if they still do?

Aisin, I believe still produces the drive train for Toyota, as well as my 1980s Samurai.

 

I honestly don’t know why that issue could occur. I’ve seen Tnshooter mention this issue a few times over the years and so I have thought about it on numerous occasions. I can’t come up with anything specific related to viscosity that would cause that.

There is a shield of sorts already in there blocking fluid from flinging straight into the breather tube. I don’t know that that is the purpose of it, because the AWD full time diffs don’t have that shield. So I have a feeling somehow that piece serves some other purpose, but looking at it, anyone’s first thought is it’s a baffle against oil slinging into the breather tube.

All I really know for sure is that my diff has had several changes, all with 85W-140, and that has been with 4.30 gears, 5.29 gears, and both with and without the ADD. No fluid spilling out ever. No idea what causes that issue, but in my mind it’s gotta be some sort of fundamental issue maybe in certain diffs or something like that. Like I said, the front diff doesn’t even turn in stock form and barely warms the fluid up. Parts are barely spinning in there in stock form. So for fluid to come up the tube even in 2wd makes it more puzzling, because barely anything is happening inside the diff in 2WD.

 

Not sure.
The only thing I do know is, The diff was slightly over filled.
That is IF you go by Toyota specs. Which is like 1/2" below the fill plug.
I fill it until it just starts to come out the fill plug. Wait until it stops stops coming out an put the plug back in. (Which is over full. I have nothing to hide.)

However, I've done the SAME thing with 3 different 4WD Tacoma trucks using

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 and never had it leak out the breather.
2x 1st Gens, and my current 2nd Gen.

And it only leaks out once the weather gets to BELOW 40 degrees.
Fill it full in the summer, it never leaks out the breather. Just about the time we get our first frost, it leaks.......
Also, it's CONVENTIONAL oil not synthetic. That's what ECGS said to use. So, I did......

I even knew there "could" happen before I used 85w-140. But hoped I'd get lucky.
Nope, no luck.

So, why don't I just switch to 75w-90?
Because I spent my money on the Lucas. And I had extra to keep "topping it off".
Which got old, so I stopped doing topping it off.

I have checked the fluid level. It seems to like to be about 1/4" or so below the fill plug. (Didn't actually measure, just a guess)
That's it's "Happy place". Good enough for me.