Thread: tundra/sequoia owners. Anyone experience front diff leaking after 4x4 highway driving

Has anyone had the front diff on their tundra or sequoia leak drip after driving at highway speeds for a while? I've got 07 sequoia and they dealer says this is a common problem of the gear oil foaming and pushing out of the vent tubes during high speed 4x4 driving. They have some 'fix' that I haven't seen yet but their explanaiton doesn't sit well with me since the shaft bearing out of the diff to the cv axle has way more play than the other side.

Just checking to see if anyone else had heard of this, since I would think this has to be a fairly common problem with the number of trucks out there. Trying to avoid issues down the road after the warrenty ends.

Unless you're racing in the Baja, highway speeds and 4x generally don't mix. But then, you wouldn't be driving a stock Tundra/Sequoia.

Find another dealer. Never had a problem with mine. 160K no issues and I use the 4x4 a lot. I am willing to bet that if its leaking its most likely a bad seal someplace.

Just seems odd to me that with so many all wheel drive cars on the road, that driving in 4x4 at higher speeds would cause any issue.

The shop manager said it was all documented and if I had any issue in the future it would be covered but taking his 'word' on this doesn't seem to be in my best interest. I want to get it in writing but I can just imagine the headache involved with that.

I don't get the need to be in 4x4 at "highway" speeds...with that being said sounds like a faulty seal somewhere, but their diagnosis is possible if the diff is really full and it went out the breather tube

Slippery, mostly empty highway. No need to slow right down, but putting her in 4 is a little extra reassurance. I've done it a few times. 50-60mph on the interstate is still "highway speeds" but slower than most would normally go.

I have an '06 Tundra and occasionally drive at highway speeds in 4. Never seen that, and my vehicle gets regular inspections by the professionals at BobMC's shop.

had this issue on my 03 tacoma. only happened when i drove it up to elevation, most notably LL. lengthened the vent tube while attaching a two way reservoir to catch any fluid. Never saw fluid after this home fix. make sense?

This can be caused by tires of slightly different diameters or with different wear patterns or inflation pressures.

I'll double check my pressures,but tires are brand new. The dealer added a tee to the end of one of the vent tubes and the two lengthened tubes with vents are as high as they can go. He said this was the fix toyota engineers came up with. Whatever, I pressure washed the underside so my truck and garage don't stink like gear oil and will use 4x4 less on the highway. Thanks for all the help.

Originally Posted by gaprhatr

Just seems odd to me that with so many all wheel drive cars on the road, that driving in 4x4 at higher speeds would cause any issue.

All wheel drive != 4 wheel drive.

All wheel drive typically means 1 wheel can slip and you lose all drive. That wheel can be either front or back.

4 wheel drive means 2 wheels can slip before losing drive, one at the front and one at the back.

In driving conditions with lots of traction, all wheel drive is OK, because the centre and front and back diffs will typically allow slip (either through a clutch system or just be open) so "differentiation" can occur with no damage.

In driving conditions with lots of traction, 4 wheel drive is not OK, because a front wheel and a back wheel will have to be always spinning at the same rate and they don't when you go around corners, so you end up with "wind-up" in the transfer case.

4x4 systems with lockers mean you have to watch out even more that you don't break things across the front or back diff, but you can end up with a car that drives 3 or 4 wheels.

At least that's how I understand it.

With the venting, Toyotas diff vents kind of suck (at least on my vehicle - old Landcruiser). They're a one-way valve. Lots of people replace with longer vent hoses and a fuel filter and/or a T up high on the firewall/pillars etc.

Originally Posted by gaprhatr

Has anyone had the front diff on their tundra or sequoia leak drip after driving at highway speeds for a while? I've got 07 sequoia and they dealer says this is a common problem of the gear oil foaming and pushing out of the vent tubes during high speed 4x4 driving. They have some 'fix' that I haven't seen yet but their explanaiton doesn't sit well with me since the shaft bearing out of the diff to the cv axle has way more play than the other side.

Just checking to see if anyone else had heard of this, since I would think this has to be a fairly common problem with the number of trucks out there. Trying to avoid issues down the road after the warrenty ends.

They have drive flanges, the diff spins whether in 2wd or 4wd.

Shouldn't lose any oil. Find out where it is leaking from. Oil shouldn't foam, that is bad. Try cleaning your front diff breather line, it most most likely clogged causing oil to come out somewhere. But you can't be sure until you locate where the oil is coming from.

Originally Posted by gaprhatr

the shaft bearing out of the diff to the cv axle has way more play than the other side.

What do you mean by this? If the bearing itself actually has play, that's not good. Im assuming you mean you can turn the driveshaft back and forth some, which is normal to an extent.

4 Hi or 4 lo? Locked or unlocked?

Oh wait, wrong vehicle.