99 Malibu wont downshift.

[CW383]

Hello all! I have a 99 Chevy Malibu with the 3100 v6. I have been having a problem with presumably a lockup converter switch (TCC). It is wanting to shift very hard at times and feels like its lugging the motor down at times. A recent problem, possibly related is when I try to climb a hill it pulls the motor down and creeps at about 25-30 mph without downshifting. Manual downshifting does not change this(it wont downshift) and it feels as though I'm driving with one foot on the brake, one on the gas. On a level its ok. Going to get codes checked tonight. Any ideas? Thanks!

[CW383]

Something else I noticed, going up a 25 degree hill I could only go 25mph, but the engine power did not change between half throttle and full throttle. I could hear the increase of air, and no audible miss, but no extra power. No codes other then a random missfire code. I'm confused. No idea what this might be.

[slls]

Have the catalytic converter checked, if plugged you will have a power loss.

[CW383]

Thank you! That is exactly what it was. This solved the no power problem. Car runs like a dream but......when I got out to my parants house to change oil, it had no forward gears. Ran fine on the way out, shifted a little funny, but I thought that may have been due to the new converter. Had reverse, but no forward. No visible trans fluid leaks. I added a quart, what could it hurt at that point, an just like that I had forward gears again. Still shiftinfg funny, but made it the 20 mile trip home ok. Tommorow I'll jack it up and open up the weep hole and add fluid to make sure its at the correct level. Gotta love the "sealed for life" transmissions.

[slls]

Fluid check procedure

Start the engine and allow the engine to idle until the transmission fluid temperature has reached the value specified. Depress the brake pedal and move the shift lever through the gear ranges, pausing a few seconds in each range. Return the shift lever to the PARK range. Raise the vehicle on a hoist. The vehicle must be level, with the engine running and the shift lever in the PARK range. Caution The engine must be running when the transmission fluid fill plug is removed, or excessive fluid loss will occur. Transmission fluid may be hot. Since the actual fluid level is unknown, stand clear when removing the fill plug. Have a container ready to capture any lost fluid. Do not turn the engine off with the fill plug removed, as you can be injured by hot transmission fluid being expelled out of the oil fill opening.
Remove the transmission plug.

The transmission fluid may darken with normal use and does not always indicate contamination or oxidation.
Transmission fluid (At least 104°F) 5-10 minutes at idle will give correct temp.

Does the fluid have a burnt odor or a dark brown color?Check the fluid level. The fluid level should be even with the bottom of the threaded plug hole.Is the fluid level low?
Add DEXRON® III automatic transmission fluid in increments of 0.5L until the fluid drains from the plug hole.
Install plug before stopping engine or fluid will spill out of plug hole.

Pan drop and filter change 7.5 qts
Check plug is just to the right of the passenger side axle housing , 11 mm plug, can't miss it, only one there.
Hoist is optional, just needs to be level and plug accessible.