New Kia Forte -- a lemon?

My 2012 Kia suffered a “catastophic failure” of its transmission about 10K miles. It was replaced, I got a rental, all covered by warranty. Last month I noticed a vibration as I rounded a tight curve at high-ish speed (DC beltway). It felt like mu left front tire was going to fall off. But it came and went. two weeks later, again, vibrating and now I’m noticing it is associated with acceleration. Boyfriend in passenger side says it feels like Right rear wheel, I still feel like it’s left front. Next day I drive to Virginia beach and almost turn around, the whole car is shuddering on acceleration at low speeds. I hit 95 and it settles down, but I took it in to dealer as soon as I returned. Dealer couldn’t find anything, so they rotated and rebalanced tires. I drove it home, no problem. Parked it for 2 weeks while I drove my other car. Next time I drive, vibration is back. This time dealer drives it, agrees it feels vibration, couldn’t find a cause, but maybe it’s debris on axle. Cleaned wheel wells, axles etc. Drove home no problem. Next day, vibration is back. Every time I accelerate it feels like I’m going to drop an axle, when I ease up, it decreases. Worse on curves. At constant speed, no vibration. I don’t want to take it in again unless I can point these guys in the right direction. I really want to just give the car back and say give me another one. Help!

A couple clarifications: When I say “I hit 95,” I don’t mean 95mph. I mean I-95, where I at at 60-64 mph. The car currently has 15K miles on it.

There are a lot of possibilities here as something like this could be related to a drive axle or it could be an engine performance issue.

Questions might be:
How many miles on the car currently?
How long after the trans replacement did this problem start?
Who has been doing any maintenance on the car?

The car may be a 2012 but any Lemon Law claims have time and miles limits along with a couple of other hoops to jump through so you may not qualify.
They are not going to take the car back and give you another for sure; unless you work out a trade and assume the financial liabilities associated with that trade.

One of your cv axleshafts may be defective.
The idea of debris on the axle is pretty funny! That axleshaft is spinning so fast, that any debris in the wheel well wouldn’t get stuck on the axleshaft, unless it was tar.

I’ve seen a lot of Kias with bad wheel bearings. Have them inspected for play/looseness.

dealer drives it, agrees it feels vibration, couldn't find a cause, but maybe it's debris on axle. Cleaned wheel wells, axles etc.
I don't want to take it in again unless I can point these guys in the right direction

Have you considered visiting a different dealership? Might be worth the extra effort. The place you’ve been going to seems to be maxed out and grasping at straws.

Look up the lemon law requirements on line. We search “lemon law DC” or Maryland or Virginia, wherever you live. You must have a clear record of he number of times you take the car to the dealer. If you don’t have a receipt for all of your visits, make sure that you get them in the future. Just because no money changes hands is no excuse to avoid the receipt. I had a lemon law situation in 1987 in MD. At the time, you could request a new car after the 6th visit.

And whether the problem is not related to a factory defect is not important. Any damage the dealer might do when they try to repair it is part of the claim.

Thank you everyone for comments so far. I have considered taking it to another dealer. It has been serviced exclusively by Kia (not that there is much service in the first 15K miles), especially given the transmission failure, which the dealer handled. The only exception is an oil change about 2 weeks before the transmission failed, which I had done at my local Sears. (Don’t shoot me.) It has just 15K miles, and I put on about 2-3K between the transmission replacement and the new problem developing.

I think all those comments make sense and @WesternRoadtripper has a good point: bring it to a different dealer.

These guys are jerking you around or grasping at straws at best. I’ve never heard of dirt on a shaft causing vibration. Since they pulled the transmission, they may very well have forgotten to tighten something or tighten it while not under load.
You should not have issues like that with a new car. Perhaps contact Kia of America to see what they can do.

Oh, We’ll give you a pass this time on going to Sears. You’re not doubt feeling bad enough. Don’t go there again, tho. They are morons.

I would get it into another shop (maybe a good independent transmission shop) for another opinion.

Maybe a CV shaft not fully seated, axle shaft nut not properly tightened, or even a suspension component that was not properly secured after being unfastened so as to allow the transmission replacement?

The debris on the axle bit sounds like something from a service writer or manager. Always take anything those guys (or in rare cases ladies) say with a lot of salt.

You should not have issues like that with a new car. Perhaps contact Kia of America to see what they can do.

Fully agree with @Remco. Kia of America should know that one of their dealers is incapable of solving a problem on a brand new vehicle. And you should not have to waste your time because the dealer service department is deficient.

@ok4450’s list of possible causes probably includes the true problem. Any of these should have been detected by the dealership. ok4450 could probably locate your problem in minutes, instead of the weeks it’s taken so far.

I know it’s under warranty, but I recommend you try this place:

It’s a serious shop owned by a mechanic I’m highly impressed with.