diff noise while coasting?? [Text View]

BBVX

07/12/2004, 05:50 PM

OK, for the gurus...

What's wrong with my front diff? On the highway, at anything over 40 mph, when I take my foot off of the gas we hear a grinding sound coming from the front end. When I put my foot back on the gas, the sound stops.
So, I'm assuming that for some reason, the gears in the diff aren't meshing together correctly. Is this right?? Is my backlash setup wrong??

Thanks,
Brian

SGT.BATGUANO

07/12/2004, 08:42 PM

Could be.........or cv's or bearings.

Andrey

07/13/2004, 02:33 PM

Brian, are you sure your "big meats" are inflated :) did you re-pack bearings at 30k ?

Tone

07/13/2004, 02:45 PM

TOD is the more likely cause - I have had 3 replaced for excessive noise just as you describe. If you disconnect TOD, you will be able to see if the noise goes away or even take your foot off the gas pedal. Others have had rear diffs make similar noise on the highway.

PeteVX

07/14/2004, 08:46 AM

talking of driveline noises....

at about 60 mph i hear a whine coming from the driveline, seems to be more towards the rear of the car, as i feather the gas pedal it goes away when i back of and comes back as i put gas back back on again. it goes away alltogether at about 70mph and cant be heard at 50mph either.

I have 42,000 miles and am i think the 3rd owner, i've been meaning to call isuzu and see if its covered under warranty but havent had chance yet.

Anyone have any ideas?

Pete

t2p

07/14/2004, 09:45 AM

PeteVX:
.
My VX does exactly the same thing. 38K approx. I'm not worried - I suspect this noise is common.
.
However, please inform me if you discover otherwise.
.
btw: The trans, transfer case, and front and rear end fluids were recently changed and the 'noise' remains.

Raque Thomas

07/14/2004, 11:40 AM

Pete & T2P - I have exactly the same noise at the same speed range - my VX has 22,000 miles on it, and did not make this noise until recently - as soon as I get some time, I'm going to schedule an appt to have it looked at - I'll let you know the outcome.

Triathlete

07/14/2004, 12:23 PM

BBVX,
Mine does the same thing though I would say its more of a humming noise than a grinding. Mine started after my lift was done. I know of several other lifted VX's that expierience the same thing.

SPAZZ

07/14/2004, 05:28 PM

front pinion nut coming loose?????

Bobster

07/14/2004, 08:46 PM

OK Let me get in on this one too. I first noticed the an extra transmission like noise while coasting over 40 just a few days before this issue was first posted. I have to turn the sound system below "normal" listening levels to hear it. But, it's definitely a new sound. I am at 20,000 miles on the odo. The front and rear diff and transfer fluids were changed at 15K dealer service.

Guess its truck?? And trucks make a lot of funny sounds??

yal^

07/14/2004, 09:35 PM

I got the same grinding noise after my lift. Actually it wasn't so bad before I got alignment, but now I even get bad vibration in my floor. It kicks in after I reach 40mph and its either when I accelerate or let go of gas. I noticed it's happening only around certain rpms - or maybe it's my imagination trying to put one and one togheter?
I took a mechanic for a drive the other night, and he suspects drive shaft rubbing somewhere. I was thinking I had a broken motor mount after my last off road adventures, when I tried to see if VX can balance on its nose LOL
I have an appointment with Isuzu service, so hopefully I'll get a few answers. What I think though, maybe 3" lift is too much. I have 912 OME springs and 1" coil spacers. Maybe there is problem with CV angle?
I doubt it's differential - I just got it serviced, and it was absolutely fine...
I'll keep you posted on what dealer said.

t2p

07/15/2004, 06:17 AM

yal - well of course your differential is fine ........
.
maybe the tires should be balanced again ........ ???
.

CV joint ........ ???
.
could also be a sign of a driveshaft u-joint going south .......
.
or an issue with a driveshaft slip joint ???
.
a driveshaft may also be 'dinged' a tad ....... be out of balance .....

t2p

07/15/2004, 06:22 AM

btw: The trans, transfer case, and front and rear end fluids were recently changed and the 'noise' remains
.
last evening - and again this morning - I did notice the slight noise is not as noticeable ........ so maybe the fluid change(s) did make a difference ......
.
again - I'm not too worried ....... although the VX is not as quiet as the Ford Explorer we have (that also has a Borg Warner transfer case), it is MUCH MUCH MUCH quieter than some of the 4wd vehicles we have owned in the past - and we never had an issue with those vehicles ............

PeteVX

07/15/2004, 07:04 AM

Isn't it funny how you mention something that you think is just happening to you, then you find out a bunch of others have the same problem?

Boards like this are the best thing that ever happened for enthusiasts!

I plan on calling Isuzu today to see if mine is under warranty then i'll get it in, it'll be interesting to see if we all get the same diagnosis.

Pete

BBVX

07/15/2004, 04:37 PM

...just returned from the dealer. My new rear diff will be in on Tuesday.
It sounds like this is a pretty common occurance with the VX. I'll be making sure to pay extra close attention to it from now on, assuming this fixes the problem. :)

Thanks to all,
Brian

phines

07/15/2004, 08:09 PM

Brian,
My front diff had to be replaced too. The plastic nozzle that the vent hose attaches to had broken off... as a result, water from my off-road adventures got in the differential and rusted it out from inside. You might want to make sure that hasn't been broken on yours too. If you don't know what I'm talking about, it's located on the top towards the driver's side axle.

That is probably something everyone should check who does any off-roading. You can fix it for a couple dollars and it'll save you hundreds in the end.
________
HERBALAIRE VAPORIZER REVIEW (http://herbalairevaporizer.com/)

yal^

07/16/2004, 11:59 AM

Well, it didn't go so good in my case.
After I got through the service desk a**hole (excuse my language), mechanic decided my tires are making the noise!!! I waited for 1.5h just to have the same prick come out and lecture me on the size of the tires and telling me they might void my warranty because the tires and wheels are not stock :mado2:
I protested the treatment and demanded mechanic take a ride with me.
He drove. First he was trying to tell me that all he hears is my tires and howling rack - I took off the fairing for a while.
And then the noise kicked in. He looked at the gauges, looked at me, then at the gauges again. Then he played with it for a while, very unhappy knowing I was right and he looks pretty bad right now. Finally he sold me a story that this is all wheel drive car, and is designed for the stock tires ONLY! and I should not put any oversized tires on it, �cuz I am tampering with drive train. If it was a Trooper, where you have a switch and can go back and forth all wheel-2WD, then you can put oversized tires on. TOD will not work properly with heavy tires, and that's why my problems occured

I was silent for a good while...

Then of course there was the whole thing about springs - why are they so big. So I played stupid this time. I told him my stock springs were sagging, so I put those on, thinking they would be better, but I did not do any further modification to my suspension. Besides springs are not covered under warranty, so I didn't think Isuzu would mind... ;eeko;

They bought it.

I took my baby home, exhausted and unhappy. It's still grinding somewhere, all the remedy I got was "put your stock wheels back on and see if that helps" :wtfo2:
Next time I think I am going to shave my head, grow a beard and get a few tattoos. Maybe then service department can admit openly to me, they have no idea what they are doing :sigho2:

SGT.BATGUANO

07/16/2004, 06:38 PM

BBVX,

You posted about noise in front. Now you say you're getting a new REAR diff?

Some info the lifters might find helpful. I've previously posted that when I got my Proton, it had 912's in the rear and was lifted to be level. That is BAD because.......

1) the VX has a factory rake, the front is between 1.5 and 2 inches lower than the rear.

- If you don't maintain the rake you whack the alignment.

2) Leveling with 912's in back equates to approximately a 4 to 4.5 lift on the front, which will cause serious stress on all the front diff components. You're CV's will be approaching a 45 degree angle. Even the CV boots don't like this and might tear, let in road gunk and destroy your CV's ....ask Proton Smoke (3 inch lift), he paid about $1700 to have ONE side replaced!

Another AWOL member,"Big Meat VX", advised dropping the front axle 1/2 inch per 1 inch of lift if you go more than 2 inches.

If you lift, do it in moderation.

Yal,

If it only happens in a certain gear, it's probably NOT your engine.

Check what RPM and gear it occurs at. Then, hold it in any gear and bring it to that RPM If it doesn't happen in all gears at the same RPM. That should eliminate the engine.

P.S. When testing, don't hold it at hi RPM's (over 3000 RPM) in any gear for a long time.

EX: 1st gear @ 5500 RPM for >10 seconds

Next, note what speed(s) the noise is present, get the vx into that range and take your foot off the gas and shift into neutral. Your RPMs will dropand if the noise drops with the engine RPMs then it's engine related. If the noise drops with the VX's speed in neutral, then it's driveline related.

BBVX

07/17/2004, 05:43 AM

Yeah, I just assumed it was coming from the front because they already replaced the front diff, and I figured they just didn't set it up right. Although, I did lower my front end about 2" before I took it to the dealer, just to check if it was the CVs, and it made the exact same noise at the exact same times.
I definitely agree with you about the angle of the axles, and I have already flipped the ball joints. I also sent Allan (BigMeatVX) a check for his extra set of axle brackets, so I could lower my front end, but I haven't heard from him. He's AWOL?? What's the story??

Thanks,
Brian

SGT.BATGUANO

07/19/2004, 01:19 AM

Awol or MIA, just haven't heard anything from him for quite a while. Hope he's ok.

yal^

07/20/2004, 02:28 PM

Mike: so I dropped it to neutral like you told me, on a long stretch road, at about 50mph, after I brought it to almost 25000rpm.
It started dropping gears immediately, like you said it will, and (I think, I am very mechanically challenged) right before it dropped from third to second I got this noise come on again, very briefly, but it was definitely there. When it got below 1800rpm it was smooth, and not interrupted. I brought it to a full stop before shifting back to drive...
I do not know if it means anything and I do not want to experiment with it anymore, since "engine behavioral" is absolutely not known to me. I'd rather have someone else to check it for me. Any volunteers? LOL

AnalogVX

07/22/2004, 10:56 AM

...wanna go for a ride?

yal^

07/22/2004, 11:15 AM

Just tell me when...

Bobster

08/12/2004, 07:27 PM

Problem solved ! The tranny noise while coasting was due to a slow leak in my right front tire. The tire was repaired and inflated. The noise is completely gone. BTW I did see flaking inside the rim. Got an appt Monday with the dealer to see how many replacement rims they need to order.

Anita

08/31/2004, 10:33 AM

Originally posted by Bobster
Problem solved ! The tranny noise while coasting was due to a slow leak in my right front tire. The tire was repaired and inflated. The noise is completely gone. BTW I did see flaking inside the rim. Got an appt Monday with the dealer to see how many replacement rims they need to order.

Ditto on this. I had the same whining noise while coasting. Prepared myself for the worst and began reading this thread. I remembered noticing that my right front tire seemed low on air yesterday so first thing today I would check air pressure and fill if necessary. This morning I walked to the truck only to notice the tire was flat! Got my neighbor to pull my full spare out of my basement and Auto Club did the rest. Now no more whining.. at least from the VX. ;Dr;

Narsus

09/20/2004, 05:23 PM

I have this same grinding noise on my 2001 STOCK vehicross. It only started about 2 months ago, and I'm looking at about 36,000 on the odo right now.

This is one of two problems that recently started happening. I let off of the accelerator anywhere from 70-15 miles per hour and it's loud enough for me to hear it over the stereo (which is pretty darn loud). I'm definitely going to take it into the dealership in my copious spare time. I'll post what they find out.

The 2nd problem is a very large hiccup when I'm in 2nd gear and going into 3rd at about 30mph. The tranny makes a big BUMP noise and the VX jerks a little more than I'm comfortable with. Does anyone have any idea what I should suggests to the Isuzu dealership, since our Isuzu shops here in Denver pretty much suck.

Narsus

09/20/2004, 05:25 PM

Okay, I posted before I read that last post. I'm a moron. My right front tire was really low, and I filled it up this morning. It was down to like 15psi, so I'm assuming a slow leak. I'll post what I find out, but still go to the dealership for the BUMP.

Anita

09/20/2004, 05:27 PM

Narcus,

I bet it's due to the low tire.

Your second problem sounds a lot like the Mode Switch. When it starts to go out it really bangs changing gears.

PeteVX

09/21/2004, 07:00 AM

OK so i posted on this thread a while ago about my diff noise at 62-65mph, i then posted again somewhere else about an unpleasant experience with Isuzu HQ and their condescending attitude.

Well, i finally took it into the dealer a week ago, they were great!! First the shop manager went for a drive with me, confirmed the noise, said it was the diff (he could actually hear it slowing down or coasting too which i couldn't)

They took the car in a couple of days later, stripped the diff down but when the parts arrived the next morning there was something missing so they rebuilt the diff again so i could have my car back, were very apologetic and said they would take it back in again when the parts arrived. Talk about a completely the opposite of dealing with isuzu HQ.

Everything will be covered under warranty....GREAT!!!!!

I mentioned to the shop manager about ISUZU HQ, he said it might be to do with isuzu cutting back US operations, they have sold their assembly plant which they apparently shared with Subaru, the only vehicle they will now sell is a car which they have built for them by someone else. There have been some rumours about money problems or restructuring and coming back in a few years. But his biggest concern was they would lose customer loyalty which has taken years to build up, especialy whilst they have been getting great reviews for their small SUV for a few years now and has been selling really well.

Isuzu are apparently still strong in europe and asia, its just a US thing.

Anyone????

VR4-Quest

02/06/2006, 12:29 PM

BBVX, so what is the common problem with the rear axle, what was wrong? Is your VX lifted?
PeteVX, is yours lifted?
Mine never made the noise till I lifted it.............and I do have an extended warranty but feel the dealer wont cover it becuase of the OME912 spings, unless I play stupid.......

BBVX

02/06/2006, 02:32 PM

Lifted, and big tires, neither of which was my problem.

My rear axle was out of alignment, from going offroad, alot. There are (for all intents and purposes) 3 rods that hold your rear axle in place. 2 go front to back and 1 goes side to side, well I bent them ALL ! This was causing rear driveshaft vibration.

We took them off, straightened them with a jack, and have been good ever since. I noticed a similar noise recently, faint but growing, but I greased all the fittings on the rear driveshaft and it went away.

Brian

VR4-Quest

02/06/2006, 02:54 PM

Well wait, you mentioned the dealer getting you a new rear axle, what does that have to do with the bent rods, or did they lead to the failure of the rear axle?
Guess Im trying to figure out if this is a rear axle or rear axle placement issues, and if its amplified by lifting the VX (the rear locating rod angle does change with a lift, and so would the "placement" of the rear axle), not just from possible off-road abuse.
As it sounds like everyone that lifts the VX has this vibration issue, and I would like to have the solution to fixing it.

BBVX

02/06/2006, 06:40 PM

If I recall correctly, we thought the rear diff was bad shortly after the front diff was replaced. Sure I was beating on them more than your normal driver but they would still be under warranty. They ordered me a new rear diff and it took several weeks to come in. During this time, the service department got a new manager, so when I took it in for the diff replacement, they looked closer and diagnosed it as bent stabilizer and lateral rods, which weren't covered under warranty.

They wanted almost $1200 for the three bars and I said no thanks. We straightened mine and it's been fine since. Even if it didn't fix the problem, I would have bought a stronger set of pre-bent bars from stinkyfab for about half the price.

http://www.stinkyfab.com/images/slinks02.jpg

http://www.stinkyfab.com/index2.html

In hindsight, the driveshaft issue made more sense because the vibration would have been transferred into the T-case, making me hear the noise much farther forward in the vehicle.

Although lifting the vehicle by adding taller springs does slightly move the axle to one side, I don't think it would be enough to cause a vibration (noise) as bad as mine, if any at all. Maybe it's time for a new thread with a "lift vs. noise" poll?

Brian

Lashsquat

02/07/2006, 07:37 AM

I can tell you this, i replaced both my rear u-joints and had the driveshaft slip joint "i think its called lubed ,and the same noise you described is gone.
Hope this helps.

Mikeys00vx

02/07/2006, 09:16 AM

My "whine" was from a slow leak in the right front tire. When the pressure got down to around 25 psi...I could hear the whine. It concerned me at first..but now I know when I hear it the tire pressure is low.

Mikey

VR4-Quest

02/07/2006, 12:19 PM

Obviously there are several types of driveline noises associated with low tire pressures, defective axles, etc. but there seems to be a common issues with noise after lifting. I know for sure this to be the case as mine made noise on the test drive after installing the OME912's, and was fine before. We need to put our heads togther and figure this one out!

Again, Im talking specifically about a driveline derived noise, after lifting the VX with OME912s or equivalent, happens most notably when letting off the throttle at highway speeds (above 60 mph). Its accompanied by a grinding noise and vibration that can even be felt through the floor (fairly severe). There is also some noticable increase in vibration at lower speeds (around 40 mph).

I have lubed the U-joints and drive shaft, and check the level of all driveline fluids and there was no difference.
I have not yet changed fluids nor had the front bearing repacked lately.
I have maintained the factory rake (front 1" or more lower than rear) and the noise still exists.

Please add your comments, solutions if any, and feedback concerning this so we can determine the root cause!

IndianaVX

11/13/2007, 10:41 PM

ive started noticing something similar, tell me what you think.....i am stock, factory rake,just rolled 70,000 :( i havent packed my bearings, or done my winter checklist yet either.
what im hearing is at lower speeds than mentioned thru this thread. as im driving thru town, or wherever, at 30 mph, when im comming up to a stop sign, for example, shortly after i start to apply my brakes, or even when i just let off the gas, i "hear" a sound like the transmission whinening down. its not grinding, it sounds smooth, not clunky. i also notice this noise when coasting down hill. but when im going UP a hill, and let off the gas, i dont hear this noise. it is very similar type sound as a bad brake pad rubbing on a rotor, kinda.......
i dont hear that well anymore after a surgery i had, but i do hear this, above the constant ringing, and pulse i have in my ear. i dont really have a clue as to wether it has gotten louder, or my hearing has gotten better enough for me to notice this noise, but now that i know its there, its got me in OCD mode, and i am listening to it intenly trying to determine where its coming from, and if it sounds "bad" or normal, which again, is hard to do when you dont hear in stereo, so to speak. but it "feels" like its coming from t.o.d, or tranny.
it sounds like its a pretty common noise. but like i said, im not lifted, and most of the previous post are from lifted vx's. oh, my tires are inflated properly too.
SUGGESTIONS??? check my fluids, and roll with it?
thanks guys for any input
and if your a veteran, it goes double......

david

ZEUS

11/14/2007, 08:31 AM

SUGGESTIONS??? check my fluids, and roll with it?
I think that is a great start. Check fluids or change them, grease all fittings, repack bearings first; then diagnose. Who knows, you might find something when you get underneath it...

Ascinder

11/16/2007, 11:34 AM

http://www.vehicross.info/forums/showthread.php?t=12009

fixed

IndianaVX

11/16/2007, 09:40 PM

fixed my problem for 75 cents, (for the air pump) yeah, i know.....
i had filled my tires up just two days previous to the post, but there was a bit of a cold snap, and apparantly i lost 10 lbs of air in my right front, and that was making the wierd noise i was hearing, or actually the tire was making the TOD make the weird noise.
so yeah, a bit embarassed, but ill live...........

Viatcheslav

12/12/2009, 12:27 AM

Sprey

12/12/2009, 12:41 AM

Any body have solutions of this problem? I have the same noise in my JDM VX, it lifted about 4 cm with springs from Trooper.
Please help me the noise is very bad!

Ive got the noise as well after lifting, and i have a jdm vx too.

Viatcheslav Are you driving in Tod all the time or 2wd?

I think with mine say im doing towards 100kmh and i coast i can hear the noise in TOD , but i think when im in 2wd the noise isnt there?.

Tho after greasing up the driveshaft and the u-joints the noise quietens down a fairbit.

Ill have a play 2mrw and see if the noise is louder in Tod or 2wd.

The noise i have sounds like a chaddering noise.

Polie

12/12/2009, 12:56 AM

Well, I know with my zuk its the splines on the drive shaft that causes the SAME noise when decelerating. Its caused by the splines having less contact surface vs stock and being slightly worn from years of use.

Not sure if it helps, but there ya go :)

Viatcheslav

12/12/2009, 03:05 AM

Ive got the noise as well after lifting, and i have a jdm vx too.

Viatcheslav Are you driving in Tod all the time or 2wd?

I think with mine say im doing towards 100kmh and i coast i can hear the noise in TOD , but i think when im in 2wd the noise isnt there?.

Tho after greasing up the driveshaft and the u-joints the noise quietens down a fairbit.

Ill have a play 2mrw and see if the noise is louder in Tod or 2wd.

The noise i have sounds like a chaddering noise.

I am driving in TOD and 2 wd, but I heared this noise when TOD and 2 wd but in TOD the nose rather more than in 2 wd.
First of all i think something wrong with u-joints I have replaced it but nothing happened then i replaced rear diff the noise still there.
Now I think the noise happen becouse angle of drive shaft changed as compared with stock.
What lifted your VX in centimeters now?
I have planing to change trooper springs for stock i hope it help.
Sorry fo my English :grino: