Thread: New Hilux Auto Transmission Shudder?

Originally Posted by Flyblown

I suggest you get in under your vehicle and measure the heights of the diffs, transmission etc. You’ll find that they are a lot higher than 300mm… there’s two Gen 8 GUNs and a Gen 7 KUN in my driveway and I’d estimate the top of the rear diff to be between 450-500mm, and the transmission breather is at least 700mm.

I don’t want to sound mean spirited but if you’re going to get into a debate with Toyota then you need to get basic facts right. If you say 300mm to one of the people you’re arguing with, it won’t help. Go measure them properly.

When you’ve done that hold the tape measure up against your doors and note how deep you must’ve been to get water into the transmission. Again, not wanting to be mean and accusatory, but I am wondering how deep the water was and how long you were sat stationary in it…

The very first thing I do to my 4WDs is fit raised diff & gearbox breathers. The very first mod, when they’re brand new. Unfortunately not enough guys know to do this. Water ingress was bad enough on traditional manual boxes but with the trick autos these days it’s a disaster as you are finding out the hard way. This has been debated elsewhere at great length and one of the conclusions was how annoying it is that none of the manufacturers fit raised breathers to 4WDs. And also how important it was to understand maximum wading depth and how to traverse water crossings correctly.

The debate about whether the dealership should have flushed the transmission from the get-go is one thing, but how the water got in there in the first place is quite different and I think you are going to struggle to get them to cover this I’m sorry to say. They’ll simply say that you went in water that was too deep.

Extended breathers are only part of the fix - the axle seals are a real weakness as the design of the seal is to keep solids out and lubricant in, not to keep fluids out. There is only a wiper lip on the outside of the seal, and it really only keeps chunks off the inner fluid lip which deflects lubricant back into the case. With marine applications, we've been having some success fitting slim series seals which are usually a little over half the thickness of standard seals and installing them in tandem back-back (one seal normal way round and the inside one reversed). This allows packing grease into the space between the seals, and despite this I've still found water ingress between the two seals in the grease between the seals! This is on hydraulics gear that's immersed in water and operating so doesn't have the same contraction problems.

I've not really found a successful way to do the back-back seal thing with automotive applications, as the recesses are designed to fit the seal they ship with and that's your whack jack. 'Marinising' the seals by replacing the tension spring with an O-ring and giving a more consistent tension on the seal lip helps, especially if your seal keeps chucking the spring out and destroying itself (often a sign of a bit of shaft runout out at the seal area). But as soon as you dunk the seal in water, especially if it is hot and it cools rapidly you are liable to drag water in past the seal into the case. This is on all shafts, not just axles so the transmission and transfer cases are liable to have this happen as well. The Safari I had for a while had a buggered PTO shaft for the gearbox driven winch, this used to drag water in as soon as the thing got wet. Pain in the arse!