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Drive train vibration Dealer can't find it

9K views 24 replies 10 participants last post by  busadave 
#1 ·
Hi Folks, Newbie here,

My Bone stock 04 Impreza, auto trans, Wagon, is my daily driver, and is one of the best cars I have owned. Lately I have been feeling a vibration in the drive train when I have a passenger or two, or if I have the car loaded down with tools, golf clubs, stuff. It is fine when it is just me and no luggage. But apears under heavy load or bogging situation.
I took it to the local dealer, I have 1 mo. left on the factory warranty, for them to check it out. Me and two techs piled in my car for a test drive, Yes they did feel the vibration. We went back to the dealership and lifted it on the rack.
The tech checked the CV joints, U-joints, Carrier bearing, mounts, ect. and could not find anything. They sent me on my way $130.00 later with no resolve.
My question, Is it normal to feel the vibration under heavy load? Could it be deeper than exterior components and be inside the trans ? Anyone have this problem in their car?

Any info or feedback is appreciated.

Thanks.
 
#2 ·
First off, welcome to the forums.

The only thing that comes to mind immediately which couldn't be easily seen are the tires. As they get old they break down like anything else. Sometimes they will occationally break down to the point at which when they have more weight on them they don't roll evenly. It is also possible that you have a defective tire which dosen't show problems under just the weight of the car.

Some questions:

1.) What make, model and size are your tires, when did you buy them, and how much tread is left, approximately. If you're really ambitious, place a nickel in the tread like this and take a picture.

2.) Have a good look at your tires, are there any signs of dry rot or any cracking where the tread meets the sidewall?

3.) Are there any odd looking sidewall issues, such a bulges or anything of the like? You can use a flashlight at a low angle to the tire in the early evening to see these, shine it across the tire's face and look for shadows not made by lettering or texturing.

4.) When was the last time you had your tires ballanced, and have you hit any big potholes lately? I'm asking this because they'll usually tell you if you have a bent wheel when they ballanance tires, and some bends will only affect ride quality with more weight. That and potholes can bend rims. (I learned this one by experience sadly)

Any more information would be appreciated.
 
#3 ·
I did think about tires but it's hard to say. I have the original tires that came on the car. I haven't had them balanced lately, I'll give it a try to eliminate one possibility.
It realy feels aparent in the drive line, like when you are bogging in too low of a gear and you feel a shutter, until you down shift. When I do down shift the vibration is still there.
 
#4 ·
The stock RE92's are not that good of tires lol, A couple things you could also look at is jack the car up so the tire is off the ground and put one hand on top of the tire and the other hang on the bottom and try to shake the tire so see if there is any slop, do this to all 4 tires, this could mean you have a bad bearing, another thing is jack the car up and use safety jacks and get under there and check the carrier bearing where the two driveshafts meet in the middle and try and move that up and down to make sure there is not a significant amount of play in that. Also give the U joints a good looking at as well. One more check with the car running check your transmission fluid to see if its low or really dirty.
 
#6 ·
Let me add on to VD5505's idea and be very blunt.

The RE92's are outrightly horrible tires. The ones that came OEM on my current Accord were replaced after about and a half and 18k miles. In addition to having very poor traction and noisy ride, they also didn't wear well at all, two of my 4 were out of round enough to cause shimmy at highway speeds.

At the time, the RE92 OEM's for the Accord were selling on tire rack were 50 bucks each, any decent tire for the car was going for 125-150 a tire.

For what it's worth, I'd put the RE92's out to pasture. If you're unsure, you can find a tire shop that does roll-out measurements and have them check the tires, however if they're not behaving badly without the car loaded, they probably won't catch anything but some of your money.
 
#7 ·
Thanks Guys for the replys and input. It looks like the majorty of you think it is the tires. I do have the OEM Potenza RE92's, they are in fairly good condition, no cracks or saw toothing. I did just rotate them but not balance them. I'll make that happen next week.
As far as VD5055 noted, I did have the car up on the rack at the dealer, the tech and I did check all the conection points, U joints, CV joints, Carrier bearing. I did notice the Carrier bearing has some movement in the rubber bushing and housing, but seems tight, The tech did say between he and the master tech on site they have never had to replace a drive shaft or bearing in their carriers.
The Trans fluid is clean and full, I did buy a Trans Filter while I was there. It looks like the lube shop who did my 30K service, flushes the trans but dosn't replace the filter. I honestly feel the vibration is coming from the trans or driveshaft. It happend when I first got the car with 10K mi. and a car load of passengers, but hasnt happened since a few weeks ago when I had her loaded up again.
 
#9 ·
On the driveshaft there should be a little washer looking deal welded on the driveshaft somewhere, look to see if that is still on there or any type of wight welded on that somewhere, I'm wondering if that came off and threw your drive shaft out of balance. Another thing is maybe your tranny is on the edge of going out, another idea is take it to a transmission shop and have them look at it. The 4EAT trannys are not that strong anyways haha. I hope the best of luck to you and lets us know whats going on.
 
#10 ·
+1 VD5505

I didn't even think of it, but yeah, you could have lost a shaft ballance weight. If you do I'll be amazed, I've only seen one go absent in 15 years of screwing with vehicles. I don't know if it would change things enough that you'd only feel vibration when the car is loaded down, but then again dynamic ballance is just a wierd thing at all points.

Getting even more interested in thsi thread.
 
#11 ·
Update

I changed the Tranny filter that should have been changed during the 30K service,WTF. I felt a little improvement in the feel and shifting, I do notice when the car warms up after driving 20-30 min I can feel the slight vibration. When I feel it I put the car in netural and coast, the vibration goes away,

I'm really lean'n towards trans problems.

I'll be driving to Portland next week, I'll beat on it and see if I can't irritate the condition, to where the dealer can find the problem.

T
 
#17 ·
I bought mine before they had 2 versions. I think that means it is closer to the raceversion in stiffness. I don't think they are that bad but I already have the outrigger bushings, Grp N tranny mount & pitch stop and the tranny subframe bushings so I may just not notice anymore.
 
#18 ·
I've got the full Energy Suspension polyuerethane bushing kit. Basically, every rubber bushing in the car has been replaced. The only one I haven't replaced is the impeller bushing on the driveshaft. The only complaint I have is there is a lot more road noise.
 
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