06 Tundra, front diff., 15K mi, Amsoil SVG 75W-90

[btanchors]

A BIG sigh of relief here! After the 3rd UOA (the one prior to this one) I thought I was headed for trouble. When I received that UOA, I took these steps:

1) I performed three short change intervals in an attempt to "clean" out the residue from the unit, and

2) I obtained and installed a magnetic drain plug.

When I changed the front differential fluid after taking the current sample, there was a small to moderate amount of wear particles on the magnet - a black, almost sludge-like material on the magnet, which I of course cleaned off before re-installing the drain plug. I refilled the front diff with the same oil, Amsoil SVG. My extended warranty runs out at 100K miles, so I think I will take a sample for analysis at an interval of another 15K miles,which would put me at about 96.5K miles on the vehicle, enough time to report to the Toyota dealer under warranty if the UOA indicates a problem. Comments?

 

[chubbs1]

What in the good Lord's name happened in that 2nd to last run??? Smart to flush the dif out because it worked. I wonder if that could have been a mistake by BlackStone? Though they don't make mistakes too often

Anyway looking like what ever happened is overwith, but like you said be sure to check it again before Warranty is up.

 

[unDummy]

Finally looking good and the way it should always look.

Late onset gear set break-in?? The gears never broke in until somewhere between 30k-58k. There must have been some 4wd usage in that mileage range. I also want to believe that some dirt got into that 30k-58k fill.

Look at those insolubles. The magnet is doing its thing. Any wear that gets caught by the magnet is wear that won't compound itself.

I understand the warranty check before 100k. But, there is no reason why this fluid can't go 30k now.

 

[btanchors]

unDummy,

Agree with all of your points. My wife, who is an engineer of sorts, asked me a very reasonable question for which I did not have a good answer.

I showed her the latest UOA results, and how dramatically low the iron level had dropped. I then explained that I felt this could be attributed to the magnetic drain plug, which did have a small to moderate amount of sludgy particles on it, which I cleaned off when I drained the oil.

So then, the wife said, "So the differential internals could still be wearing at an abnormally high rate, but it is being masked from showing up in the UOA results because the magnet is removing those particles".

I thought about this and realized the same statement could be attributed to any UOA result involving a system with filters or magnetic plugs in them. Given this statement, how would you respond?

 

[INDYMAC]

I think the earlier Fe levels were just a reflection of how little you use 4WD, and sometimes not at all. The front diff internals were just rusting. As Toyota states in the owners manual, it's a use or lose system. At least once a month for 10 miles is mandatory for proper internal system lubrictaion.

 

[unDummy]

Engineers always want to throw some fuel on the fire and forget about the fire extinguisher.

Yes, the magnet will mask some of the wear. But, some wear is caused by wear compounding itself. And, I've never seen a magnet single handily dropping wear by over 1000ppm. You could also say your 'rinse runs' washed the diff clean. So, we're not seeing the residual 1000+ppm leftover gear oil in the diff too.
Typically, with a gear box magnet, if I'm not seeing a needle, bearing, or a chipped tooth, I'm fine with it.

Don't forget that your rear-end has a magnet too. What was its UOA like? and the transfer case with its built in magnet? So, the magnet does reduce PPM but will not mask a failure.

See anything in the drain pan? I'd wager that the gear oil poured nice and golden too. This will warn you along with the magnet. The older UOA measured high wear. But, the situation is unknown why.

I haven't read an owners manual in years. But, most 4wd systems do need a monthly run as IndyMac stated. This was actual common sense years ago to splash everything with lube. But, its too much to ask for from the consumer of today and often forgotten. And, many 4wd systems work even in 2wd use. The Tundra's front end doesn't have manual hubs. The front diff spins with the tires. I'd have to look at the transfer case but would wager that if it has a pump, its pumping even in 2wd.

 

[Hokiefyd]

Originally Posted By: INDYMAC
I think the earlier Fe levels were just a reflection of how little you use 4WD, and sometimes not at all. The front diff internals were just rusting. As Toyota states in the owners manual, it's a use or lose system. At least once a month for 10 miles is mandatory for proper internal system lubrictaion.


I'm not sure this is true. An '06 Tundra should have "automatic" front hubs which, as I understand it, are engaged all the time. So whenever the vehicle is moving forward, the gears in the differential are spinning. So even if you're not "in 4wd", the entire drivetrain still spins.

An easy way to check this would be to reach in and try to spin a front half shaft by hand. If I understand the Tundra's system correctly, neither of the half shafts should spin (since they're connected permanently to the front wheels, as in a conventional FWD hub).

Very different from, for example, my old '95 Nissan 4x4 pickup. It had manual front hubs, and if the front hubs were unlocked, the front drivetrain did not spin when you drove. You could reach in there and spin either half shaft by hand with the truck parked on the ground and with the transfer case in 2wd.