Hacc

I just bought myself a 98 gs400 with 170000 miles on it. when i bought the car it had OEM 16inch wheels on it and the car was vibrating allot so i changed them to 17inch Oem rims with 235/45/17 but the vibration was till there i thought it might be due to rear bearings to i changed all 4 bearings, changed the brake pads upper arms, my cars drive shaft had some lose bolts got them fixed but the problem was not solved, thinking that it might be the tires so i again changed them this time OEM 18inch rims with 245/40/18 the vibration this time was almost gone but when i drive my car around 80mph i can still feel the rear vibration which is coming from the left side of the car what is the problem with this car please help me with it as i have wasted plenty of time and money on it has some one else faced the same issue, .........sorry for my bad English

Sampak

Just to make sure it's clear, you did get the wheels and tires balanced by at least more than 1 shop before throwing them away for something completely new and different? And also bigger wheels & tires will usually cause more imbalance issues to crop up since there is more mass in the wheel, and if there's a bad one or 2 it'll need to be balanced with even more counter weight (or the proper way by mounting the tire's heavy side on the opposite side of the wheel's heavy side, and go from there).

Changing out random suspension parts (unless they really were worn) is just waste of money unless you can isolate the issue first.

Also, more detail is needed. WHEN does it vibrate? At what speeds? Does it go away at certain speeds, or get worse with higher speed? Have you checked the shocks for leaks -- a bad/worn shock will allow any road imperfections to cause the attached wheel to bounce all the time down the road, which leads to that vibration you feel.

mcharity

I agree. Sometime the stock rims are bent near one or more of the spokes.
It's not visible to the eye but it'll cause the rim to not balance correctly; It's also non-repairable.

As a general rule, I try to avoid used rims because it's hard to know how many pot holes they've battled over the years.

Hacc

Thanks all for replying my gs vibrates at speed of 40mph then goes off and comes back again at 80mph to 100mph but I go above 100mph i can't feel any vibration I am also planning to install new rims tomorrow as I have tried new tires today on the same rims but it was of no use I will also get the rear shocks checked by tomorrow if there is anything else I need to check please let me know I have also noticed that if someone sits at the back vibration increases

Sampak

You're talking about new wheels and tires again. You haven't mentioned if you have gotten the rear tires balanced, and how many times, and which method (simple spin balance is not very accurate, "Road force" balancing is a similar but better and is usually great). How many tire shops have you taken all these different tires and wheels to get mounted and balanced, more than at least 1-2 times each to make sure they are not making any errors?

If you can first make that clear, we can help troubleshoot other parts, instead of wildly going through wheels and tires hehe.

Hacc

Well I got my rear tires balanced at least 4 times and from different shops I have also swapped my es 17inch rims and tires which doesn't vibrate on my es with my gs and it's having the same issue

Sampak

Well ok that helps. If it is a rhythmic vibration related to car speed, and not somewhat random, then it definitely is something along the driveline. Maybe the rear brake rotors and drums needs to be checked for any hangups, or even anything on the CV axles.

Hacc

One more thing I want to add is that when I change the gear from p to d or r to d I can hear a clunk sound coming from rwar I also tried the same 18 inch rims and tires on my es and there is no vibration so my mechanic told me that there might be a problem with the rear defrential or cv joints my drive shaft seems to be good but today when I jacked up the rear tires and started my car shifted in d drive I could hear my drive shaft shaking my mechanic also saw it now his suggestion is to change the rear defrential along with axel any suggestions

First pic is Gs on 235/45/17
Second pics GS on 245/40/18

Hacc

Ok I was almost done with the new differential but while bolting differential flange they won't match so I hhad to remove the differential again and checked for the difference my cars previous differential had to 15 written on it and the new one that I bought had 17 written on it but the place where I bought this differential told me that it's for a v8 Gs now I will have to swap the differential flange any suggestions

Hacc

Thanx bro I will drive my car today and if the problem is not sorted I will get a new drive shaft from a junk yard

GS4_Fiend

iTrader: (22)

It's possible the axles are causing the vibration. Since you say it's coming from the rear.

mcharity

This is way out there and probably not likely but...
Remember the movie "My Cousin Vinney" when Joe Pecci had mud on the rims of his Caddy which resulted in a serious vibration?

You don't have any debri clinging to the draft shaft/wheels, do ya?

Hacc

Ok here is the current situation I have changed differential,axel bought new rims tires now the car run far much better than before now there is slight vibration so I took it for alignment I was told that the gear mount is broken so now back to garage I normally used to hear thug sound when shifting from P to D may be this was the problem I will keep updating you guys

MurderClub

Hacc, I am having this same issue. Did you ever find the problem? I would appreciate any input.

Thanks

Hacc

bro i did a road force balance this has almost solved the problem but not as i wanted it still vbirates after a quick launch vibrates in 1 gear to 2nd and then goes off. i am planning to change the drive shaft now.