Vibration at 70 MPH

[LT4John]

I am having problems finding the source of a vibration in my 96 LT4 between 70 and 80 MPH. I have had the tires balanced twice and checked for roundness, but it's still there. The front tires are new and the rears are only a few months old. The vibration does not seam to come up though the streeing wheel, the rear view mirror vibrates.
Can the driveshaft or half shafts give me this kind of problem, and if so, how do I test them? I am concerned about put the car up on jack stands and driving the rear wheels up to 70 MPH.
Any help would be great, thanks in advance.

 

[nyernga]

Hi Neighbor,

It could be the u-joints. Best way to check is raise the rear end, grasp the shaft and see if there's any play in it.

Len

ps: a group uf us locals are getting together for a cookout on march 5th here in Conyers. If you're interested let me know. We do this several times a year as well as take trips to Helen......

 

[JEFNLSA]

I had the same problem w/ mine. Had the tires/wheels balanced on the Hunter 9700 Road Force Balancer and problem solved.

I don't know if you are familar w/ this system but it applies force to the tire and shows where the rim position should be in relation to the tire. They then take the tire and spin it to the marked position on the rim and...bingo.

A regular spin balance will not show the problem or correct it.

I would give that a shot. Do a SEARCH on Hunter 9700 and you'll see that others have had same results.

 

[Vettelt193]

I am having problems finding the source of a vibration in my 96 LT4 between 70 and 80 MPH. I have had the tires balanced twice and checked for roundness, but it's still there. The front tires are new and the rears are only a few months old. The vibration does not seam to come up though the streeing wheel, the rear view mirror vibrates.
Can the driveshaft or half shafts give me this kind of problem, and if so, how do I test them? I am concerned about put the car up on jack stands and driving the rear wheels up to 70 MPH.
Any help would be great, thanks in advance.

did you take it to the same shop each time? did it vibrate before the new tires? some shops are lazy and won't do a full balance, they will just do it on the outside.... if you can find a shop with the hunter, as JFNLSA suggested, take it there... you won't get a better balance

If you are confident the balance is done correctly then:

the u-joints (as already mentioned) is the place to start... if you don't want to jack it up to check for play, you can go down the road, keep it in gear, and get on and off the throttle.... if they are bad you will usually hear a clunking coming from the rear

 

[Moonunit 451]

I am having problems finding the source of a vibration in my 96 LT4 between 70 and 80 MPH. I have had the tires balanced twice and checked for roundness, but it's still there. The front tires are new and the rears are only a few months old. The vibration does not seam to come up though the streeing wheel, the rear view mirror vibrates.
Can the driveshaft or half shafts give me this kind of problem, and if so, how do I test them? I am concerned about put the car up on jack stands and driving the rear wheels up to 70 MPH.
Any help would be great, thanks in advance.

Could be a lot of possibilities, there are drive line shops that will check the balance of your shafts. It's way expensive to do aluminum though. u-joints, a bad tire and wheel bearings are frequent causes, but your car isn't really that old for this type of mechanical problem.

HEY! DON'T RUN YOUR DRIVE TRAIN UP TO 70 ON JACK STANDS! :eyerole

 

[Robertwav1]

I would do a search on this forum...there is some information regarding the tranny. If I recall it's some type of valve that can be changed by dropping the pan. I have the same problem with my car but haven't addressed the problem yet. Just in case the other remedies don't solve the problem.

 

[LT4John]

Thanks everyone for thier responses. This weekend I will check the u-joints and and if I can't find anything I will find a shop with a Hunter 9700 Road Force Balancer and get the tires rebalanced.


nyernga, Thank you very much for the invite but I will be up in Canada that week.

Regards, John

 

[JEFNLSA]

Go to www.gsp9700.com

On their site you can find one in your area.

 

[badabing9]

greetings,

i had a vibration that i was not sure where it was coming from in my 88. the steering wheel felt of but, i could not pinpoint it. i had noticed that the rear view mirror vibrated so that i realy could not get a "clear image" of the vehicle behind me, especially at night and with tinted windows.

i then developed a "squeek" with every wheeh rotation on the drivers rear wheel. i checked the bearing and observed no play whatsoever as well as the rear u-joints. six days ago i was flat-bedded home with the drivers side rear wheel area developing a "clunk or a knock" with every rotation.

i replaced all the rear half shaft u-joints and wheel bearing assemblies. upon examination of the bearing, saw nothing unusual and the same with the u-joints needlle bearings. i have done other vettes and have seen what caused the problem but, not on this one, especially since the car has 73,000 orig miles. however, it is to note that i no longer have a vibration in the rear view mirror nor do i have a squeek in the wheel area. for you, this may be a preview of things to come......i hope not though!

 

[Vrotate]

The Shakes

I had the same problem with my old 85. I ended up replacing the Half Shafts. Fixed the problem. Check to see if the balancing weight is gone from the half shafts..

 

[LT4John]

I checked out the rear end this weekend and all the half shafts and U joints look good. I did find that the left rear wheel bearing had some play in it when I moved the wheel up and down. The right side was good, no play at all. I bought a new bearing hub assembly and now I am gong to try and replace it myself.

Question, the spindle nut looked to be a 1 1/2", but the socket I bought is a little large, does anyone know the correct size of the rear spindle nut and also the size of the Torx head bolts? I have a Haynes service manual (what a waste of money;(, but it does not state any sizes or even if the spindle nut is a left or right thread. Any help with this rear hub replacement process would be great!!

 

[Baldie88]

Here's a suggestion that might help. I had a similar problem with my 88. Started vibrating at about 60 and got progressively worse the faster I went. Found out that 17 years worth of grease and brake dust had built up on the insides of the wheels. Cleaned them real good with Simple Green and a stiff brush and presto, no vibration. This might not solve your particular problem but is worth a look.

Ron
Baldie88

 

[wishuwerehere82]

Hi all,

After doing a search I came across this post on balancing.

I have been thrashing around with my tire balance problems.
My 98 has been shaking a little at 60 MPH, so I got my tires spin balanced at a local tire shop.
After the balance which I got them to do, taking the tires off myself and hauling them down to the shop, the Vette shakes like a craftmatic vibrating bed.
The tires have almost 11,000 miles on them and a lot of tread left.
The tire shop told me that two of my wheels are out of true, and they put a total of 90 Grams on one of my rear wheels to "balance" it. A few days later, I threw one of the 45 Gram balancing weights and the shake was a lot less.

Today I put about 45 minutes on the Vette on the NYS Thruway at between 70-90 MPH and it just about shook my fillings out. So I have to do something else now.

I'm going to take it to one of the shops locally that has the Hunter 9700 balancing system and see if it helps.
Thanks for the info.

 

[Robertwav1]

One other thing to check...I had a problem at 140MPH (race track of course) with a vibration that was significant. Turned out one of the brake rotors was not cut straight. I seen it for myself as the hub was mounted in the lathe. There are different holding chocks for the rotors and the vette has an exceptionally deep hub, if the wrong one is used...well...might be worth looking into if all else fails.

 

[wishuwerehere82]

One other thing to check...I had a problem at 140MPH (race track of course) with a vibration that was significant. Turned out one of the brake rotors was not cut straight. I seen it for myself as the hub was mounted in the lathe. There are different holding chocks for the rotors and the vette has an exceptionally deep hub, if the wrong one is used...well...might be worth looking into if all else fails.

My rotors are brand new, so I doubt that's the problem. This all began when I got the tires re-balanced.

 

[Achilles]

I checked out the rear end this weekend and all the half shafts and U joints look good. I did find that the left rear wheel bearing had some play in it when I moved the wheel up and down. The right side was good, no play at all. I bought a new bearing hub assembly and now I am gong to try and replace it myself.

Question, the spindle nut looked to be a 1 1/2", but the socket I bought is a little large, does anyone know the correct size of the rear spindle nut and also the size of the Torx head bolts? I have a Haynes service manual (what a waste of money;(, but it does not state any sizes or even if the spindle nut is a left or right thread. Any help with this rear hub replacement process would be great!!

Try looking at the thread "Rear hubs or other". There is some info that might help you. The socket size for the spindle nut is a 36mm. You also need a #55 Torx bit.

 

[Mart]

Hey cool that's my thread,

The Jerk is right, 36mm hub socket, and T55 torx bit, if your looking for tips to get them out let me know, liquid wrench and a few days of soaking on both the hub bolts and spindle nut.

Oh, and a long bar to loosen the spindle nut.

Mart

 

[354RwHpLT4CE]

half shafts and bearings

Do yourself a favor,pull the half shafts to do the rear wheel bearings.You will need to pull the camber rods and the rear tie rods before that though.Its worth the time.While you have the half shafts out,you might as well do the wheel bearings too.I happen to have a set of the solid u-joints if you need some.They are brand new from www.vansteel.com( P/N hs-07),I'll sell them for $20 each.Vansteel wants 27.99 + shipping.They are not spicer,but are heavy duty type.

 

[wishuwerehere82]

Hi all!

I got my wheels balanced today and that Hunter GSP9700 machine is a wonderful tool to have around. Everything runs so smooth now, even at 100!
Thanks for all the good advice and helping with the vibration problem.