I recently purchased a 1992 400E with the 4 Speed Transmission.  Buying the car I knew it has some problems shifting (hard shifts).  So I went and drained the fluid, changed the filter and put it some MB Transmission Fluid.  Drove the car around for a while and checked the level, perfect - right in between low and full.  Today I went for the first longer drive (about 100 miles mixed highway and city driving) since purchasing the car and noticed the following issues:

• Whirring sound in 1st and reverse
• 2nd gear is skipped in all scenarios - 1st goes to about 3200RPM then shifts for a fraction of a second into 2nd then into 3rd (slightly above 1000rpm)
• 3rd shifts into 4th at the earliest at about 3200RPM
• Kickdown from 4th to 3rd works fine with good, firm shifts
• Kickdown from 3rd to 2nd results in bouncing off the rev limiter 
• Kickdown from a start has 1st go all the way to redline and stay there bouncing off the rev limiter - lifting from the gas results into a hard shift into 3rd

Any insights into what might be wrong?