Want a car, but it has bubbles in transmission fluid

A 2006 sonata I’m looking at drives well and everything seems to work. Of course the last thing I check is the transmission fluid, which came out dark and had bubbles. They seem to dissipate when the car is in neutral, but came back when I put it in D or R. Is this something to walk away from or is it possibly over or underfilled?

If you are looking at the dipstick, is it overfull or underfilled. You are the one with eyes on the stick here.

It may just need to have the fluid and filter changed and it could possibly have the wrong ATF in it. Does it have a record of the ATF being flushed at a quickie oil change place?

Ah records. The seller had all these service records but nothing for the transmission that I saw. The filter is always suspect, but on ~2001+ Sonatas are not user serviceable because the unit has to be removed from the car. The pan is sideways and the filter is buried under a bunch of stuff or something.

Drove and shifted fine (has a slap stick). But it was kind of dark and the reading was all over the place, so I wasn’t sure. I was going to look at the car again and maybe bring some fluid with me because I suspect it’s low. If it happens to be at the correct level is it a lost cause?

“Dark” transmission fluid is one of the best reasons to walk away from a used car.
Why would you even consider this car with an apparently unmaintained transmission when it has the potential for needing an overhauled transmission in the very near future?

Used cars are like commuter buses.
If you miss out on one, another one will be along shortly, and hopefully the next potential car will be one that has had proper maintenance.

Make sure the fluid is at the proper level. If it is overfilled, it can foam up a bit. Maybe that is what is happening.

Myself, I’d be disinclined to purchase any vehicle with a design that required the automatic transmission be removed to drop the pan and change the fluid and the filter. To even consider it, I’d either need a huge discount off the bluebook price, or require the seller complete this service on his dime before the sale.

All that said, it could well be that there’s nothing wrong at all other than some discoloration in the fluid, and something else major will break long before the transmission fails.

Edit: Good idea to check that there is no sign of transmission fluid in the coolant.

My vote is for walking away from this one. The age combined with the dark fluid and bubbles could mean an expensive problem and with Murphy’s Law always present that problem may surface 3 months after you buy the car.

Bubbles can also be caused by a problem with the valve body in the transmission; sometimes due to warpage.
If the price of the car is right (as in heavy discount) it might be worth a shot along with a fluid change.

The possibility always looms that the seller has been given some disturbing news about the transmission in the recent past and has decided to throw in the towel while playing a bit ignorant of the situation. I’m not saying that’s the case here; only that it happens. A lot.

We are not sure how much bubbles you are seeing or how dark the fluid is. If the fluid has not been changed, it is going to be dark. It does not necessarily mean that the transmission is going to give out in a month, but then when buying a used car, you have to be a bit paranoid.

How is it priced? Sometimes, I just assume I need a new transmission and factor that in the purchase price, if it works, then might be worth the gamble. If you are paying fair market price, you might be the last owner.

@VDC If it’s dark, walk away, since damage to the transmission has already occurred.

I have stated before if there is even a small red flag raised look elsewhere. Recently someone said they only had 4000.00 to spend and could only find cars with problems. I checked AutoTrader in the area they claimed to be in. There were 818 sedans for 4000 or less listed. You can not tell me you could not find one that felt like you could just purchase and start driving. You will have problems with any used car but why start out with problems?