Need to change a tranny

I need to know of a site or something with instructions on how to change the transmition on a 1999 Hundai Sonata.

We own a Hyundai Sonata it broke down a few years ago and had to replace the car because the transmission wouldn't shift, well we found out from a friend who is a mechanic that the place that was servicing it put engine oil in the transmission by error, is this fixable, what kind of problems could it cause and would they cause permanent damage to the transmission?

A very good site for fixing Any Hyundais is hmaservice.com register for a free account and it has all the factory info you will need.

We own a Hyundai Sonata it broke down a few years ago and had to replace the car because the transmission wouldn't shift, well we found out from a friend who is a mechanic that the place that was servicing it put engine oil in the transmission by error, is this fixable, what kind of problems could it cause and would they cause permanent damage to the transmission?Yep - the clutch packs (which engage reverse and the various forward gears) are TOAST until replaced during a rebuild. If you still have that car, and if it's a '96 or later Sonata, and you intend to get it running again, make sure whoever does the rebuild ONLY uses SP III automatic transmission fluid. There are NO aftermarket equivalents. Period. SP III is a proprietary ATF only available through Hyundai, KIA, and Mitsubishi dealership parts departments - and, yeah, it's pricey, which is why a lot of independent transmission shops cheap out with DEXRON III and a booster fluid that allegedly converts to automaker spec fluid. You found out the hard (also spelled $-$-$-$-$) way neither that nor engine oil works in Hyundai automatics.