I recently bought an 1994 XG manual ute, and have noticed that at over 90km/hr when the engine is under load in 5 gear (eg. going uphill), there is a rumbling noise heard from somewhere in the car. It is hard to pinpoint, but it seems to be coming from underneath the car.
I have checked uni joints, have changed gearbox oil (replaced with transmax z), diff oil. Oil came out clean out of both diff and gearbox.
The noise slowly disappears if the accelerator is released.
I have noticed I have noticed the large cast iron weight bolted onto the extension housing of the t5 gearbox, and packed with rubber. When I bought the car it had a bad extension housing leak, and fluid leaked all over the rubber. It is now very soft and it is easy to wiggle the cast iron weight. Could this be the problem?

Any help much appreciated, as I am about to go on holidays!

Cheers

Drove home today most of the trip was on smooth hotmix roads. I particularly noticed that the rear grumbles a lot when accelerating uphill.

When I drive over a hump or depression in the road at speed, I heard a loud rumbling. I am now thinking it may be the rear wheel bearings?

Anyone ideas?
Cheers

On boxing day I got some time to rip out the both back axles, and press off the old rear bearings. Both felt very notchy when I checked them by hand.

I pressed new timken bearings in the drivers side rear, replaced axle shaft and tightened up bolts. When I grabbed the wheel with and checked for end float and play, there was none! But when I done the passengers side rear bearings, replaced shaft there was about 0.8mm of end float when all bolts were done up.

On the road the suspect side growls when going over bumps and up hills (even down hills sometimes)etc.

How could I adjust the preload on the suspect tapered bearing?
I was pretty sure that there was no adjustment in rear wheel bearings!