Diff or Wheel bearing noise?

[LittleBeast]

Looking through my old VX.info files I found something on this, maybe it will help:

ZEUS
Site Supporter 1999, black, VX, 1031
Salt Lake City, UT US
Member Since: Dec 2005
Posts: 1,474

Let me tell you, 4.77's make some noise! I figure my new mud tires will help mask that humming! And just the opposite of the first post... if you start to hear a racket when you take your foot off the gas when going down the highway, it could be the preload on your pinion is too tight or too loose. Either way, the pinion bearings create a lot of noise and a lot of heat when they are out of spec.

Green Dragon
Super VXer 2000 Dragon Green VX 0485
Virginia City Highlands Nevada, nv us
Member Since: Jun 2002
Posts: 380

A whine interpretation from Great Britain

"Usually a noise on accel or decel means a ring & pinion mesh problem. This generally requires diff replacement or rebuild. However if this is the case, they will go a long time with no problems other than the noise."
------------------
Phil Prince
ASE Master Technician
Factory trained
Jaguar & Land Rover Tech

Moncha
Administrator 2000 Proton Yellow 0584
Pueblo, CO US
Member Since: May 2002
Posts: 1,871



The pinion gear (Ring gear) can be shimmed to get rid of the noise. Unless something else is wrong with it.
rowhard
Site Supporter 2001, Dragon Green, 1342
Olympia, WA US
Member Since: Dec 2005
Posts: 951



Joe, I'll be honest, it could be as simple as a backlash adjustment that you can eliminate with shimming. BUT, it takes special tools for measuring and knowing what the heck your doing. Yes, any mechanic with the training, tools and spec's could do it, just finding one that would do it. Most just want to replace something, not repair it. And yes that is the name we call it. The British I believe call the ring gear a crown gear, can't remember what the call the pinion gear off hand. If you have the workshop manual downloaded into your home computer, it starts on page 334
MY2000 lsuzu Hombre



Gear Noise
Gear noise (whine) is audible from 32 to 89 kmlh (20 to 55 mph) under four driving conditions.

1. Driving under acceleration or heavy pull.

2. Driving under load or under constant speed - -

3. When using enough throttle to keep the vehicle from driving the engine while the vehicle slows down gradually (engine still pulls slightly).

4, When coasting with the vehicle in gear and the throttle closed. The gear noise is usually more noticeable between 48 and 64 km/h (30 and 40 mph) and 80 and 89 km/h (50 and 55 mph).

Bearing Noise
Bad bearings generally produce a rough growl or grating sound, rather than the whine typical of gear noise. Bearing noise frequently “wow-wows” at bearing rpm, indicating a bad pinion or rear axle side bearing. This noise can be confused with rear wheel bearing noise.

Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while coasting at low speed with transmission in neutral.
Noise may diminish by gentle braking. Jack up the rear wheels, spin them by hand and listen for noise at
the hubs. Replace any faulty wheel bearings.

Knock At Low Speeds
Low speed knock can be caused by worn universal joints or a side gear hub counter bore in the cage that is worn oversize. Inspect and replace universal joints or cage and side gears as required.

Backlash Clunk
Excessive clunk on acceleration and deceleration can be caused by a worn rear axle pinion shaft, a worn cage, excessive clearance between the axle and the side gear splines, excessive clearance between the side gear hub and the counterbore in the cage, worn pinion and side gear teeth, worn thrust washers, or excessive drive pinion and ring gear backlash. Remove worn parts and replace as required. Select close-fitting parts when possible. Adjust pinion and ring gear backlash.
MY2000 Isuzu VehiCROSS Workshop Manual Page 1

[wintermute]

Thanks for the great post, littlebeast. Some very good leads and info.

[lasturbo]

Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while coasting at low speed with transmission in neutral.
Noise may diminish by gentle braking. Jack up the rear wheels, spin them by hand and listen for noise at
the hubs. Replace any faulty wheel bearings.

Has any member "Replaced Rear Bearings" yet because there is nothing in the workshop manual how to do it (unless I am blind) and what special tools and/or presses are needed to get the bearings off the axle shafts.

[etlsport]

just looked through our vehicle repair program. there is a time listed to replace the rear wheel bearings (1.7 hours per side) but no instructions or even diagrams for it

[SilverBullet75]

Great question...
Anyone ever replaced the rear wheel bearings?

Also, has anyone ever had a read diff actully fail?
What does it do? Grenade?

thanks,
---JIM---

[Lucian08]

I was about to post about a vibration noise, and this post came up as a suggestion to review. After reading through it, I seem to have similar issues to at least one or 2 others. My situation being that I have no noise until I hot about 40mph; after that there seems to be a vibration noise under acceleration or maintaining speed. No sound when letting off on the gas, and no sound under 40mph no matter driving style. One extra nugget of info is that I had this noise (or what I remember being this noise) both on acceleration AND deceleration; I hadn't driven in a couple months and just installed a diff drop (been sitting in the garage for far too long) and now the sound only seems to be as described above. I thought it may have been the CVs (and I had wanted a diff drop), but now I'm sure it must be something else. Front Diff? Rear Diff? I'll have a passenger drive with me this week to see if its coming more from front or rear, but the fact that it did change somewhat after the diff drop leads me to believe it is front related. Thoughts? The last post ended with the question of anyone actually having to replace a wheel bearing or diff; has anyone? Noise come or go after such a repair or upgrade?

[djvx]

I was about to post about a vibration noise, and this post came up as a suggestion to review. After reading through it, I seem to have similar issues to at least one or 2 others. My situation being that I have no noise until I hot about 40mph; after that there seems to be a vibration noise under acceleration or maintaining speed. No sound when letting off on the gas, and no sound under 40mph no matter driving style. One extra nugget of info is that I had this noise (or what I remember being this noise) both on acceleration AND deceleration; I hadn't driven in a couple months and just installed a diff drop (been sitting in the garage for far too long) and now the sound only seems to be as described above. I thought it may have been the CVs (and I had wanted a diff drop), but now I'm sure it must be something else. Front Diff? Rear Diff? I'll have a passenger drive with me this week to see if its coming more from front or rear, but the fact that it did change somewhat after the diff drop leads me to believe it is front related. Thoughts? The last post ended with the question of anyone actually having to replace a wheel bearing or diff; has anyone? Noise come or go after such a repair or upgrade?

Have you replaced diff fluids & transfer case and trans fluid lately? Greased the driveshaft? Sounds to me like normal noisy vx drivetrain, but my best reduction of the vibration was greasing the driveshaft, definitely helped. Tons of threads on vibration but Id do the fluids if you haven't lately. The vibration could be a driveshaft balance issue. Maybe you dented it?

[Lucian08]

I drained and replaced the front diff fluid when I did the drop last weekend. I'm gonna grease the driveshafts (is that as easy as it sounds?) and change the oil in the rear diff hopefully this weekend. The noise has slowly increased over time, so I doubt the shaft is dented but I'll give it a once over when I'm under there. If all else fails I'll just get a louder exhaust and hope it doesn't explode before my next upgrades.