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Strange vibrations

Hi everyone, I own a 1999 Kia Sephia with 120,000 automatic transmission. I just recently notices some odd vibration when I drive my vehicle. I can feel it in the accelerator. It also vibrates my whole front portion of the vehicle. It sounds like some kind of gear is just missing the other set of gears causing like a clicking noise.



The strange part us that it happens only sometimes and is most pronounced when turning but does happen when I accelerate on a straight away. It does not happen really when I go over 70 mph.



A bit of background, I had the transmission rebuilt at 100,000 and the front left and right CV joints were replaced at that point as well. It sounds and feels almost like when my transmission had gone out. What I suspect might be the cause is when I was going on a 400 mile drive earlier today on a certain bridge they had these plates with signs specifically saying go over them at 45mph, after the first few plates I had accelerated to 65 without realizing it and drove over about 3 of those. I think they were an inch thick but noticeable when driving over them.



This confuses me a little because it only happens sometimes and usually starts when accelerating or turning. If I would let go of the gas the sound would sometime stop. To me it seems like it might be some kind of front end problem from these plates but I also think it could possibly be a transmission problem.



I’m going have it checked out tomorrow when I rotate my tires but I would like some idea before I go into the shop.



Thanks for your help and if you have any questions I’ll be happy to answer them.

You must really like this car.

Did you have all four CV joints replaced, or just two, and if just two, which two?

Going over bridge plates is unlikely to be the cause. Not impossible, but unlikely.

You’re describing a vibration in one sentence, and a noise in the other. The vibration could be from worn engine mounts, worn suspension components, or who knows what else.

The clicking noise on acceleration/turning sounds like CV joints, which is why I asked how many were replaced. If the outer joints were replaced, but the inner joints are now going bad, they could, potentially, cause some drive train vibration.

I’m not a transmission expert, so I can’t comment on that other than to ask, “Did the rebuilt transmission come with a warranty?”

One more question; How does one accelerate from 45 mph to 65 mph in a Kia Sephia without realizing it?

Well I do like the vehicle, its surprisingly reliable. It was the front two outer CV joints that were replaces.

Its a vibration that seems to be a result from the clicking sound or rather whatever is causing that clicking sound.

The clicking noise is also present on straight aways which is why I don’t think its a CV joint.

I am more concerned about it being some sort of gears that are not aligned properly that will eventually wear out and my car breaking down in the middle of no where… or worse yet an expensive repair bill.

Pretty much it makes a clicking or grinding noise between two gears (this I think is a more accurate description of the noise) noise, and vibration in the vehicle. This happens with turning or a straight-away intermittently.

And about the 45-65 it was 4 in the morning with no cars to be seen, and well I tend to accelerate in those conditions, then I see the plates and not really have time to decelerate until the second plate but not fully, 65 mph the first, 60 the second and 50 mph on the third.

A inspection to ensure everything is still tight (after all the work you had done is in order) maybe the big nut on the CV shaft is not tight,also any exaust system contact with body.

I fear you have an inner CV joint going out. I am a little surprised they did not replace the half shaft(s).

Yeah I’ll be going to the shop today, thanks for all your help! It probably is some loose bolt, I hope.

One other bit of information if it sparks any ideas in someone’s head, when all this happens I can let go of the accelerator and when I reapply the accelerator the sound is gone.

Thanks for all your help guys!

Just an update, It was the CV Shaft that popped out of the differential. The CV shaft was not damaged but they are having some trouble putting it back into the differential. They are going to pull the transmission and they think something is blocking the locking mechanism in there (something along that line), I’m starting to think this has nothing to do with those metal plates. I’m expecting it to be covered under my warranty with the company, makes me glad I opted for the 3 year warranty when I got it rebuilt.

-Sam