Engine braking noise

[Sleepn]

So I have this stage noise that seems to have developed in my ute, wondering if anyone might be able to give some ideas...

When im downshifting into either 3rd or 2nd mainly, as this seems to be the most resistance on the engine braking, just since yesterday morning the ute seems to have decided to make this sort of grinding noise up the rear..

It happens only when using a pretty strong amount of engine braking, so letting the clutch out reasonably fast, it only lasts for a second or two, and doesn't happen once its properly in gear and decelerating, just that initial slow down. If I let the clutch out slowly and let it just gently slow down then it doesn't make the noise, I didn't do anything stupid when it started yesterday..

Its a 07 hilux double cab, low km's... got me beat at the moment as to what it could be, back pressure on the diff gears? I haven't checked the oil in the diff, doesn't have any leaks though.

Cheers

[zukmeista]

Do you match the revs when you change down? Makes it much smoother and won't waer out the clutch as much.

[Sleepn]

Not really, the sound seems to be coming from a bit further back than the clutch, I could certainly mask the problem by driving slightly differently, but the noise shouldn't be there in the first place so something isn't quite right..

[Crash bandicoot]

pinion bearing?

[2.8SURF]

Play it safe and drop the diff oil and inspect for any metal particles on the magnetic drain plug. Small amount of metal in very fine almost dust form is normal but any chunks on the plug and something bads happening.

For the sake of the cost of a few litres of diff oil its worth checking and repairing now if its only bearing rather than leaving it and stuffing the diff gear teeth as well.

Also worth changing the gearbox oil while your at it, I do mine once a year for the gearbox and 6 monthly for the diffs, only because they take a regular drowning and I havent gotten around to fitting breathers yet, but you can never change the oil too often as $50 oil always beats a $1500 gearbox rebuild

[Sleepn]

Found the problem, was a flap of metal that had bent over into the path of the driveshaft, was right beside where the rubber center bearing support was, so on a hard downshift it would move against it and touch...