2000 Sonata drivetrain whine

Several months ago we purchased a nice, low-mileage (22,000) Sonata
GLS with 2.5 V6 and 4-speed automatic from a local Hyundai dealer.
About two days after we purchased the car, the transmission failed
right in the dealer's lot when we took it in for a minor service! They
handled the problem without quibble, installing a new transmission and
giving us a loaner during the service. (Fantastic warranty!)

However, since the transmission has been replaced I've noticed a
high-pitched whine that seems to be coming from the drivetrain when
under load. It is most noticable at part throttle around 25 to 40 mph.
I don't think it's an engine or belt noise as the pitch varies with
road speed, not engine speed; higher road speed yields a
higher-pitched whine. (Does not change when shifting gears.) Also when
you let up off the gas there is a delay of a second or two before the
whine goes away. Doesn't sound like tires as far as I can tell. I'm
not very familiar with these cars mechanically, but on other vehicles
I would suspect a touch of pinion or torque converter whine.

When the car was brought back for an oil change I reported the noise
to the service manager, who later said the tech couldn't reproduce it.
(Admittedly it's not a very loud noise, but it is noticable and other
Hyundais I've since driven in don't have it.) They asked that I take a
drive with a technician to demo the noise, which I'll do at the next
oil change.

In the meantime I thought I'd ask here: anyone have an inkling of what
could be causing this? Obviously if there is a serious problem
developing I'd want it taken care of while the car is still under
warranty!

 

Sounds like a little bit of gear whine from the differential in the
transmission. Different transmissions have different magnitudes of this
noise. It doesn't sound from your description like there's any real
problem. I'd be reluctant to put another transmission in, because based
on your description, I think there's a reasonable likelihood the next
trans could be worse.

 

To add: but do by all means drive with the dealer and let them make a
decision. If they think it's excessive, they'll be happy to fix it.

 

Thanks, I'll take a ride with one of the dealer's techs to see what he
thinks.

What's the deal on these transmissions? This is our first Hyundai.
Very nice car overall; comfortable, solid, lots of room, good pickup.
We're thinking of keeping this car a year or two and depending on how
things go possibly buying a new Sonata or Santa Fe. But while
searching around for info I've run into stories about the automatic
transmissions being problematical in these vehicles. (Certainly
failing at 22,000 miles is not a good thing, but you can't really draw
a general conclusion from one car.) If these trannies have had
problems are they improved in the newer models? Any tips on extending
their life?

 

Hyundai had a huge transmission issue once upon a time, but the last of
those transmissions was in the 1998 Sonata. Since then, Hyundai has been
making constant improvements and I see no continuing transmission issues
with their newer models. Have a look in the consumer reports reliability
charts. Elantras (2001 & newer), Sonatas (1999 & newer), Tiburons (2003 &
newer), and Santa Fes all use the same basic automatic transmission
design, so they should be able to provide some interesting comparisons.

 

Well actually differential is not a part of transmission, but it probably
doesn't matter to you.