Growling Rear Drivetrain Need Help with Pics and Video (1 Viewer)

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Around 550 miles away from home on the way back from a funeral this last Saturday, we started to hear a low pitched whine (growl?) coming from the rear of the :princess: LX-450. It started almost unnoticeable until it was quite loud.

It's constant with the speed of the vehicle. From a few miles an hour to highways speeds it's noisy. Around 72mph it's somewhat quieter. Accelerating, decelerating or steady speed, the noise is there. Only changing pitch with the speed of the vehicle.

I headed to some streets with hills to do some testing.

With the transmission and transfer case in neutral, coasting down a hill, the sound is the same. Coasting down the hill with the drivers door open, the sound is definitely coming from behind.

We considered a one way rental car, but drove the LX-450 home anyway. The noise didn't seem to get worse.

At home, I put the car up on four jack stands and had the :princess: in the drivers seat with the speedometer up to 15mph while I probed the rear drive train for noise. I cobbled together this thing for the job:

The long end of the hose on my ear while I probed with the other end while the truck was running in drive on the jack stands at 15mph. It seemed noisiest near the rear diff flange, but the pitch seemed higher. The "growl" was very noticeable standing and facing either of the rear wheels. Whatever is causing the noise, the rear axle housing is doing a great job transmitting the sound out to the ends of the axle shafts.

While using the ih8mud search, it was mentioned that you could pull a diff plug and quickly put your thumb over the drain hole. Allowing inspection of the diff plug magnet with very little diff oil loss. Here is the magnet:

See the wire in front of the plug, that came from inside the diff and was stuck to the magnet. What part inside the axle housing has a wire? Note: This LX-450 does not have diff lockers.

In this video you can hear the sound at all speeds:

While I was under the truck today I checked the rear u-joints. I can move them very slightly. I made sure the rear u-joints were well greased. No change in sound after greasing up the rear u-joints.

No up/down play on the rear diff flange.

I'm thinking this is something in the rear diff.

Any ideas?
 
frank,
is it an actual wire or is it a shaving of metal?

could it be rear wheel bearings going bad or something rubbing in the brake calipers?

you could also remove the rr driveshaft and drive around to see what changes
 
"While I was under the truck today I checked the rear u-joints. I can move them very slightly"

Can you post up a video of that?
 
frank,
is it an actual wire or is it a shaving of metal?
It's wire. Not brittle and sharp like a shaving. Bendable.

could it be rear wheel bearings going bad or something rubbing in the brake calipers?
My first thought was a wheel bearing. But when it was up on jack stands with the wheels spinning, it sounds the same on both sides. I would expect a scratching sound with the calipers.

you could also remove the rr driveshaft and drive around to see what changes
I'm going to do that. While under the truck today, I couldn't get the bolts off. I sprayed them with PB Blaster and will try again.

Thanks James!
 
Around 550 miles away from home on the way back from a funeral this last Saturday, we started to hear a low pitched whine (growl?) coming from the rear of the :princess: LX-450. It started almost unnoticeable until it was quite loud.
SNIP

In this video you can hear the sound at all speeds:

While I was under the truck today I checked the rear u-joints. I can move them very slightly. I made sure the rear u-joints were well greased. No change in sound after greasing up the rear u-joints.

No up/down play on the rear diff flange.

I'm thinking this is something in the rear diff.

Any ideas?


I was thinking maybe the pinion bearing, since I had previous experience with that in an FJ55. Then you indicate no play in the rear diff flange. But it may still be bad and not give much play in the rear diff flange.

On the other hand, that much junk on your magnet plug seems to point toward a problem in the third member. If your pinion bearing already spit that out, I kind of think things would be far worse at the rear diff flange than the evidence for that otherwise indicates.

The "wire"? That's weird.
 
Possible pinion or diff bearing. Thats a good amount of shavings on the diff plug, depending on the last oil change. Firstoy suggestions is the best as far as eliminating the transmission and TC, but i truly think one of your bearings are toast. Be carful before you ruin your gears when the bearing goes.
 
Has the differential been opened previously and could that wire be from a wire brush?? When I did my front axle service for the first time I found a detent ball in the bottom of the knuckle that had apparently popped out of a socket extension bar.
 
"While I was under the truck today I checked the rear u-joints. I can move them very slightly"

Can you post up a video of that?
After it was greased, I couldn't move it.

that much junk on your magnet plug seems to point toward a problem in the third member. If your pinion bearing already spit that out, I kind of think things would be far worse at the rear diff flange than the evidence for that otherwise indicates.
I think it's in the third member. All the noise is in that direction.

Possible pinion or diff bearing. Thats a good amount of shavings on the diff plug, depending on the last oil change.
Last diff oil change was done soon after we bought it just over 3 years ago. It was done by our mechanic.

Firstoy suggestions is the best as far as eliminating the transmission and TC
I'm going to try that first.

I can't imagine it being the TC. The noise is definitely loudest around the third member. The TC is quiet. Unless this noise is the rear u-joint. If its the rear u-joint I'd imagine a change in sound or pitch after I greased the u-joint.

The "growl" was very noticeable standing and facing towards either of the rear wheels (when it was up on 4 jack stands). I imagine the noise is being resonated throughout the axle housing.

but i truly think one of your bearings are toast. Be carful before you ruin your gears when the bearing goes.
I already have a lead on a good third member. I'll try without the rear DS first. If the noise continues, I'll likely swap the 3rd member along with new wheel bearings and seals.

Has the differential been opened previously and could that wire be from a wire brush??
Possibly. It has FIPG not the paper gasket.
 
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I would pull the rear drive shaft, drain the fluid, pull the axles, tape the hub holes and test drive. If it is the diff, the noise will be gone, if not it is the wheel bearings.
 
I would pull the rear drive shaft, drain the fluid, pull the axles, tape the hub holes and test drive. If it is the diff, the noise will be gone, if not it is the wheel bearings.
If its the rear wheel bearings, would the rear hubs get hot/warm?

I checked on the 550 mile drive back home at each stop. The hubs on both sides were only slightly warm. Both rear left and right approximately the same temp.
 
If its the rear wheel bearings, would the rear hubs get hot/warm?

I checked on the 550 mile drive back home at each stop. The hubs on both sides were only slightly warm. Both rear left and right approximately the same temp.

Depending on what is going on, maybe, maybe not. Did you check the diff temp? If it is the wheel bearings, the axles have to come out, if the diff the drive shaft also has to come out. So I would pull them and give it a guick drive to confirm.
 
I'd think that the sound would seem louder on one side than the other if it were a wheel bearing. Maybe have someone sit in the middle of the back seat, then lower the window on each side to see if they can discriminate whether one side is louder?

And would a wheel bearing failure create the junk that the magnet picked up out of the diff? However, it wouldn't be the first time that an obvious sound is unconnected to other evidence of what turns out to be a separate problem.
 
A quick update from last night:

t-case and put it in neutral. then grab the drive flange and try and move it up and down. If some play then not so good.


I did this, no play.

move the drive flange in a rotational manor(back and forth) see how much play is in the pinion.

I did this. Not much play. Maybe a 1/4 inch.

dump in some 90-140 gear lube(conventional/ dino) cheap gear lube in the diff. If the noise changes some(less noise at least until the lube warms up)


I did this (with 85-140). The noise remains. I don't notice a difference between cold and driving around a while and warming up.

When I went to re-fill. There was more "fur" on the magnetic drain plug. Not as much as a few days ago but plenty. I also noticed metal filings in the oil up in the drain hole when looking up inside.
 


When I went to re-fill. There was more "fur" on the magnetic drain plug. Not as much as a few days ago but plenty. I also noticed metal filings in the oil up in the drain hole when looking up inside.

That right there would indicate its time to pull the 3rd and look into it more. Something is coming apart, with the amount of noise and fuzz on that plug there is defiantly something bad happening, I would bet the ring and pinion are grinding them selves up.

Its only about 45min to remove the 3rd, if you replace it remember to clean the inside of the housing out well. Do not want that metal gunk getting into the new 3rd.
 
How long have the 4.88s been installed? Maybe the installer got the backlash wrong.
 
I would bet the ring and pinion are grinding them selves up.
Today, I picked up a very nice nice 3rd from Spector Off Road.

Its only about 45min to remove the 3rd, if you replace it remember to clean the inside of the housing out well. Do not want that metal gunk getting into the new 3rd.
I was telling my daughter this evening that it'll take more time to do all the cleaning than removing and re-installing.

I'll post some pics after I complete this on Saturday.
 

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