Thread: Rear diff whine

So out for a hunt this morning and i noticed that as i hit around 3000rpm i start to get a buzz/whine from the rear. This would get worse as i accelerate up to 3500rpm to more of a high pitched whine. No noise when I am coasting or braking. I'm assuming its a rear diff issue?
Truck is a 96 3rd gen Surf 2.7 petrol auto.

Any thoughts on it as to my next move with it.

banana skins in the diff does the job

Have experienced similar in two vehicles over the last 40 odd years. I thought diff, but in the D21 Nissan ute it was a wheel bearing and in the Holden (model with th 6 cyl Nissan motor) it was a diff bearing.

Worst comes to the worse you will have the pleasure of swapping out the diff head or the entire diff if you need to.

I could whine for ages yet.

I'd start looking around for a replacement diff from a non runner or a wrecked one.

Cheers
Pete

Originally Posted by gonetropo

banana skins in the diff does the job

I was thinking more volume on the stereo.

Not something I've had an issue with.

Originally Posted by gonetropo

banana skins in the diff does the job

Organic or GMO?
If they are green do they last longer? Or does over ripe ones give more lubricant?

Wife in the back seat?

It might not even be the diff, so don't panic yet. The number of times I've had someone drop a vehicle off with glum look for something apparently major, only to find a stone, plastic bag, bit of wire, bent telltale tab etc.. Get it looked at on a hoist by someone who isn't a burgalr

check fluids first, might just be really scummy. jack up the rear end and have a play with the rear wheels, bit of wobble on the rears will suggest a bung wheel bearing, need a workshop press to change them.

chances are its the above, or the shaft bearing. none are majors bbut best fix it now.

Diff noise will be speed and load dependant regardless of gear and rpm....are you sure its diff noise?

How much water have you played in?

Sounds more gearobx like. Especially if it goes away when power is lifted. I just did the bearings /gearbox in my Vitara and the input shaft was causing the issue. Bearing had not collapsed but it was not far from going.....

Originally Posted by Maca49

Wife in the back seat?

Mother inlaw???

Wheel bearings are a possibility,, they generally don't make too much noise unless absolutely rooted. Jack the truck up, wriggle the tyre and feel for play, stuffed wheel bearings often leads to oil leaks from axle seals, The oil drops into your drum brake and then weeps out the drum onto your rim.
Your other option is diff bearings, normally the pinion bearings that give trouble first. Lay underneath grab the pinion (rear of the driveshaft where it bolts to the rear diff, and wriggle it and feel for play (up/down, left/right, not rotational play) Check your diff oils for water contamination, if you have done any water crossings, or played in water over 40cm (ish) and you don't have extended diff breathers there is a good chance you have water in your rear diff, and that is a bearing killer.
Is the noise you are hearing RPM related or speed/acceleration related? If RPM related it could also be a gearbox or transfer case issue, output bearings can give up if your oil level is too low or if you get water in there, (deeper water crossings etc, no extended diff breather)
Have a good look for oil leaks around your rear diff and your transfer case/gearbox, it could point you in the right direction.

Originally Posted by ROKTOY

Wheel bearings are a possibility,, they generally don't make too much noise unless absolutely rooted. Jack the truck up, wriggle the tyre and feel for play, stuffed wheel bearings often leads to oil leaks from axle seals, The oil drops into your drum brake and then weeps out the drum onto your rim.
Your other option is diff bearings, normally the pinion bearings that give trouble first. Lay underneath grab the pinion (rear of the driveshaft where it bolts to the rear diff, and wriggle it and feel for play (up/down, left/right, not rotational play) Check your diff oils for water contamination, if you have done any water crossings, or played in water over 40cm (ish) and you don't have extended diff breathers there is a good chance you have water in your rear diff, and that is a bearing killer.
Is the noise you are hearing RPM related or speed/acceleration related? If RPM related it could also be a gearbox or transfer case issue, output bearings can give up if your oil level is too low or if you get water in there, (deeper water crossings etc, no extended diff breather)
Have a good look for oil leaks around your rear diff and your transfer case/gearbox, it could point you in the right direction.

Just reading this, will this also be an issue on other manufacturers (Suzuki Vitara perhaps?) I have had it not quite floating but barely touching the bottom once. It was a while ago so any damage is probably already done, but now that you mention it, is this something that I should think about? Diff oil etc??