Diff or Wheel bearing noise?

[89Vette]

Vibration with little to no noise = tire balance in my book.

Mine makes 'airbox noise' always has since I've owned it. Some gear noise has always been present too. It's hard to hear though since I'm running Wrangler MTRs.

Little noise in the front. Lots of noise in the back. This should be categorized in the little to alot range,,,but your point is taken. I suppose sitting in storage could have an affect on tire integrity too. (Belt distortion/flat spots.)

Also, since I've been around the block a few times, I've driven vehicles that needed their tires balanced. This feels more like [hard] bearing vibration.

[Scott Larson]

My '01 has a whine from the rear diff under acceleration only, pointing to a worn ring and pinion to my way of thinking. The VX had 150,000 miles on it when I bought it so it is completely understandable! I've changed every fluid to the recommended viscosities with appropriate additives (read, "friction modifiers") all by Amsoil and things got amazingly quiet all the way around. Still a slight whine, but I'm not complaining. I wish she had come with all her service records, but alas, she was bought at dealer auction and had none. Somebody took care of her though...

[tom4bren]

This feels more like [hard] bearing vibration.

The only sure way to tell would be to check the fluid in both differentials, the transfer case & the tranny. Look for burnt smell or dark coloring & look for any metal shavings suspended in the oil.

I know, it's a lot to go through but if it has you worried enough, it'd be worth it.

[89Vette]

Today, I noticed there's some vibration as it's revved in park -- especially when cold. Though it's possible a tune-up (or injector service) is necessary, it's not really a miss. I'm still thinking bearing(s). I confirmed this by kicking it out of gear on the hwy too. The effect directly corresponds to engine revs.

Because I'm also hearing a bit extra noise at startup, I'm leaning toward an engine accessory bearing issue. It's [somewhat] reduced after warm-up.

[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.

[nfpgasmask]

The other two have some similarity -- though there is a difference. One whines when you let off the accelerator. It's been lifted. My guess(es) on this one are either a drive-shaft alignment issue -- or -- the inner pinion bearing needs replaced. (Sound seems louder from the rear.) By inner pinion, I mean the one up at the nose. (Let me know if that's supposed to be called the outer bearing.)

I would say this whine you hear when you leff of the accelerator is almost certainly the CVs. When you lift a VX, the CVs get angled and you will ALWAYS here this sound. I am pretty sure everyone on this forum with a lift hears this sound when you let off the gas. It's nothing to worry about as long as your CV boots are ok and you don't hear any clicking.

Drivline vibration is something else however.

Bart

[LittleBeast]

I would say this whine you hear when you leff of the accelerator is almost certainly the CVs. When you lift a VX, the CVs get angled and you will ALWAYS here this sound. I am pretty sure everyone on this forum with a lift hears this sound when you let off the gas. It's nothing to worry about as long as your CV boots are ok and you don't hear any clicking.

Drivline vibration is something else however.

Bart

Haha, i don't have ANY CV's at the moment (both blew out and are totally removed) and I get the sound when I left off the accelerator really bad, I don't think that is it

[89Vette]

Today, I noticed there's some vibration as it's revved in park -- especially when cold. Though it's possible a tune-up (or injector service) is necessary, it's not really a miss. I'm still thinking bearing(s). I confirmed this by kicking it out of gear on the hwy too. The effect directly corresponds to engine revs.

Because I'm also hearing a bit extra noise at startup, I'm leaning toward an engine accessory bearing issue. It's [somewhat] reduced after warm-up.

As I said, engine noise seems the primary cause. Remember my post asking about air pump noise? I took it by an Isuzu service facility today. Tech took a quick listen. Immediately, he said intake gasket(s) leak. I asked if that would account for roughness at 2500. He also said motor mounts could be part of the issue.

This could be a combo of all 3. A little gear noise, a little mount vibration, and an accentuation by the intake (to create an imbalance in cylinder power).

Are intake gaskets really a [common] problem on these? The tech said it was a problem in general with the 3.5L motor.

[technocoy]

Just my 2 cents, but I feel like in general that the VX has a certain roughness to it. I remember when I first got mine (25,000 miles) that I for the longest time was thinking there was a bearing or a gears, etc that may be worn because of a whine or rub sound i was hearing when letting off or under certain rolling conditions.

With it not getting any worse and having grown used to it, it now seems normal, but when I drive my wife's pilot or another, more "civilized" vehicle it becomes evident when I go back to the VX that it's a bit more beastly than other cars.

It's also a bit rougher and louder in the higher RPMs than other SUVs, etc.

So, I don't want to lull you into buying something that may have issues, but the fact you have heard the same thing in three different VXs has me thinking you are experiencing the same thing I did.

Even my best friends JGC seems quiet in comparison.

Throw some dynamat in it and call it a ride!!!

Good luck.

[89Vette]

Just my 2 cents, but I feel like in general that the VX has a certain roughness to it. I remember when I first got mine (25,000 miles) that I for the longest time was thinking there was a bearing or a gears, etc that may be worn because of a whine or rub sound i was hearing when letting off or under certain rolling conditions.

With it not getting any worse and having grown used to it, it now seems normal, but when I drive my wife's pilot or another, more "civilized" vehicle it becomes evident when I go back to the VX that it's a bit more beastly than other cars.

It's also a bit rougher and louder in the higher RPMs than other SUVs, etc.

So, I don't want to lull you into buying something that may have issues, but the fact you have heard the same thing in three different VXs has me thinking you are experiencing the same thing I did.

Even my best friends JGC seems quiet in comparison.

Throw some dynamat in it and call it a ride!!!

Good luck.

Ask yourself if people would have paid $30k for the level of roughness/vibration you're talking about. Ask yourself again if the problem might have occurred on yours before the 25k mileage point? Certain vehicles do have "characteristics". But engineering, parts, part failures, and other aspects play a part in the final result.

Generation 1 JGCherokee's definitely have a problem with their differential bearings. They are louder and fail in a high percentage of cases. If the result is normally vibration/loudness vs breaking down, people could come to the conclusion it's just a characteristic of the vehicle. To me, it was a problem.

Again, I'm imagining what a new specimen would have felt like. Whether this is primarily the intake manifold problem, wheel bearing vibration, differential vibration, or other drivetrain bearings, it's something that could be found and improved. Or,,,you could say "Eh...whatever."

FWIW,,,the Isuzu tech did say manifold gaskets were problematic on the 3.5L motor. Whether it's true and/or he was blowing smoke, I don't know. Guess I could do a search or post a thread on that topic.

Considering how much more forgiving injection might make manifold leaks, maybe it is an issue (with the VX)? The tech called the gaskets "cheap plastic". Maybe FelPro or some other manufacturer makes a better set. Regardless, I'm trying to decide/learn how likely a manifold leak could feel like a vibration vs a miss. Maybe at just the right amount of cylinder imbalance -- just short of a lean miss??? I did also note an idle very close to an outright miss when it gets hot. I suspect this is a real issue. (Maybe it explains why the mpg is so bad (worse) for some owners?)

BTW: Compared to other 4x4 setups/brands I've driven, this Isuzu design does seem to have it's share of gear whine/drag. When you let off the gas, you can feel the drivetrain dragging the vehicle slower than other 4x4 system (i.e., Quad-Trac II or AWD car). It has more of the character of a truck,,,big truck,,,maybe even a BEAST. Probably part of the reason for the "Little Beast" nickname. Had I not noticed the pronounced vibration in park revving the motor, I might have come to the same conclusion.

I also found a thread on fan bearings causing this problem. So there are multiple possibilities. There are also multiple perceptions that could be formed from verbal description vs actual 1st-hand experience of individual symptoms.

[nfpgasmask]

That's weird because I never ever heard this noise, but as soon as I lifted, it was there.

Bart

[technocoy]

Ask yourself if people would have paid $30k for the level of roughness/vibration you're talking about. Ask yourself again if the problem might have occurred on yours before the 25k mileage point? Certain vehicles do have "characteristics". But engineering, parts, part failures, and other aspects play a part in the final result.

Generation 1 JGCherokee's definitely have a problem with their differential bearings. They are louder and fail in a high percentage of cases. If the result is normally vibration/loudness vs breaking down, people could come to the conclusion it's just a characteristic of the vehicle. To me, it was a problem.

Again, I'm imagining what a new specimen would have felt like. Whether this is primarily the intake manifold problem, wheel bearing vibration, differential vibration, or other drivetrain bearings, it's something that could be found and improved. Or,,,you could say "Eh...whatever."

FWIW,,,the Isuzu tech did say manifold gaskets were problematic on the 3.5L motor. Whether it's true and/or he was blowing smoke, I don't know. Guess I could do a search or post a thread on that topic.

Considering how much more forgiving injection might make manifold leaks, maybe it is an issue (with the VX)? The tech called the gaskets "cheap plastic". Maybe FelPro or some other manufacturer makes a better set. Regardless, I'm trying to decide/learn how likely a manifold leak could feel like a vibration vs a miss. Maybe at just the right amount of cylinder imbalance -- just short of a lean miss??? I did also note an idle very close to an outright miss when it gets hot. I suspect this is a real issue. (Maybe it explains why the mpg is so bad (worse) for some owners?)

BTW: Compared to other 4x4 setups/brands I've driven, this Isuzu design does seem to have it's share of gear whine/drag. When you let off the gas, you can feel the drivetrain dragging the vehicle slower than other 4x4 system (i.e., Quad-Trac II or AWD car). It has more of the character of a truck,,,big truck,,,maybe even a BEAST. Probably part of the reason for the "Little Beast" nickname. Had I not noticed the pronounced vibration in park revving the motor, I might have come to the same conclusion.

I also found a thread on fan bearings causing this problem. So there are multiple possibilities. There are also multiple perceptions that could be formed from verbal description vs actual 1st-hand experience of individual symptoms.

Not hearing your specific issue it's hard to know.

As for paying 30,000 for the vehicle you bring up an interesting point. Point being that no, not many people were willing to pay that much and that led to brand new VXs on lots for low and mid 20s. It's a concept vehicle that earned a short run being hand assembled. It's not an infiniti luxury vehicle.

I would say that yes, it IS possible some damage occurred prior to 25,000 miles, but seeing as how I've put another 55,000 on it with no issues I probably would say "meh, whatever".

That's not the point though, the point is that I've driven at least 6 differenct VXs one of them showroom new and they all have a rough and tumble running demeanor.

Now that being said, mine isn't exceptionally loud as some have described, but it does feel harder than other vehicles I've driven and owned.

Keep in mind that despite the cost, this is a specialty halo vehicle. There are no cupholders, etc. This was expensive because it was limited and advertised as essentially a consumer rally vehicle. It wasn't expensive because it was a smooth ride. I mean, my wife won't even ride in it it's so rough and I have Nitto Street tires on mine.

I don't doubt that there is an issue necessarily, I just think that coming from other cars to the vehicross takes some adjustment. If you keep looking for a problem on different cars and can't seem to pinpoint it it may just not be a problem. I would have to think that after you have driven several and they all have the same thing it's probably not something specifically wrong as much as it is a characteristic.

I do think I've seen several posts on here about issues with the gasket as well. A search will most definitely turn something up there.

If it's driving you that nuts, it may just not be the car for you.

Good luck! I hope you find one. I love my VX more than some of my family members.

[wintermute]

I love my VX more than some of my family members.

Me too!

[89Vette]

Family members are one thing....How bout your wife, girlfriend, or mistress? LOL

Seriously, anyone reading this thread, go start your VX. Slowly run rpms from idle to 2500rpms. Tell me if it stays smooth or gets rough. (If it gets rough, you'll feel it in the steering wheel and gas pedal.) To me, it feels like bearing vibration.