Performance Import FWD Transaxle Info

Please read the AT-Bible

and Torque Converters Explained

OK, it may not have bible status, but John from ITP posted this great write-up on DSMtalk.
It is a must read.

There is also some good info here PlymouthLaser.com

ATRA (Automatic Transmission Rebuilders Association) is another helpful site

Here are links to pages that I created:

Setting up a performance transmission

Translab Shift Kit install

End Clutch Repair

Other Transmission Seals to Replace

DSM TCU Part Numbers

The stock Sonata torque converter

In recent years, it has become more affordable and easier to find information regarding Import transaxle performance. Owning an automatic is no longer a hopeless situation.

Many argue that automatic transmissions loose too much power from drivetrain loss compared to a 5-speed. When you do the numbers, automatics generally weigh 50# more and loose 5% more power than a 5-speed (very generalized.) This 5% works out to be a 20 horsepower loss at 400hp. I feel that more consistent track times is worth the 20hp loss and I can just raise the boost .5psi to make up for it.

First, the B&M Trick Shift was the most recommended automatic transmission fluid. Then John from IPT says it is terrible. Since he works on transmissions for a living, I trust his word. Go with OEM or a good synthetic like Amsoil or Redline. Be careful who you listen to for automatic transaxle information.

IPT recommends adding a bottle of LubeGard to ATF fluids that are not OEM. This will help make the ATF closer to the OEM Mitsubishi fluid.

The two most popular upgrades are Trans Lab shift kits and end clutch upgrades. Both run around $80 each + labor if any from Import Performance Transmissions.

I highly recommend adding a transmission cooler or installing a larger one for most applications. Heat is the primary killer of all automatic transmissions.

Also, I picked up a magnetic drain plug from MagneticDrainplugs.com and a new transmission filter kit from the Hyundai dealer. Better safe than sorry. It is amazing how much debris floats around in there from normal use.

First picture of the KM177 Automatic Transaxle (before cleaning)

Some confusing markings on the transmission

Either Hyundai used the KM175 transmission case for some KM177's or this transmission has had some work in the first 70,000 miles. I recently found out that it is common to find a lower transmission marking on the case since they are interchangable. Check the End Clutch cover to see if the true model marking is there.