SOS. Clunking noise in 5th gear

[Jam3s]

SOS. TD5 Defender issue. R380 gearbox.
Currently traveling. Will contact a mechanic tomorrow. In the mean time can any provide any advice?
Suddenly cruising along the highway I started getting a clunking noise in fifth gear. Noise not apparent in other gears and goes quieter/disappears on deceleration/no throttle.
Also can hear the noise (alot quieter) when in neutral with clutch out. Noise goes away with clutch depressed.
Still have drive in all gears.

Have check propshafts and UJs. They seem ok.
Not towing
Currently near Atherton (Cairns)
I also posted on the AULRO Facebook page.
Thanks

[fitzy]

Someone with greater knowledge than me will give you more info , but my hunch is the 5th gear support bearing has failed. It is a known weak spot . Keep it out of 5th.

[djam1]

Quite likely that the rear support bearings have failed and if it's got bad enough it will wipe the teeth off of 5th gear.
You could proceed in 4th gear but you will likely need a full rebuild as this will lead to debris being distributed throughout the gearbox if you go too far
I have replaced the bearings and oil pump on one that failed seemingly without issue but it wasn't driven a long way

[Jam3s]

Thanks guys. I have only done 6 KMs since the noise started. It's an hour to Cairns so I think I will make my way there slowly in 4th gear.

[Jam3s]

Looks like it's going to need a reconditioned gearbox. Lots of noise coming from input shaft. Oil had a lot of shiny metal filing slime on drain plug.

[Markf]

Looks like it's going to need a reconditioned gearbox. Lots of noise coming from input shaft. Oil had a lot of shiny metal filing slime on drain plug.

My R380 did the same thing. Started off sounding and feeling like a bit of tyre thump in Coober Pedy. Drove it gently back home to Moe (about 1700km) and parked it up until I could get another box. My rational for driving it so far towing our camper was that it was going to end up on a flat top and every kilometre I got closer to home was a kilometre I wouldn't have to pay for on the flat top. As it turned out there was no flat top required. Whew.
Looked at lots of options including Ashcroft and ended up going with 4WDIndustries - the Ashcroft option was going to take too long. 4WDIndustries told me that my original box was a proper mess which didn't surprise me considering how LOUD the thump was by the time I got it home.

[Jam3s]

My R380 did the same thing. Started off sounding and feeling like a bit of tyre thump in Coober Pedy. Drove it gently back home to Moe (about 1700km) and parked it up until I could get another box. My rational for driving it so far towing our camper was that it was going to end up on a flat top and every kilometre I got closer to home was a kilometre I wouldn't have to pay for on the flat top. As it turned out there was no flat top required. Whew.
Looked at lots of options including Ashcroft and ended up going with 4WDIndustries - the Ashcroft option was going to take too long. 4WDIndustries told me that my original box was a proper mess which didn't surprise me considering how LOUD the thump was by the time I got it home.
Hey Mark. Thanks for the info.
It was going to be two weeks before I'd be on the road again if I waited for a reco box to be shipped to Cairns so I'm 1700km into my 2000km trip home.
Box is noisy on take off but pretty quite in 4th gear. 5th gear is no go due to loud clunking. So it's been a slow trip home.
Like you a tilt tray was going to be an expensive option.