diff noise while coasting??

[Narsus]

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]

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]

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]

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]

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]

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]

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]

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/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

[Polie]

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