W126 1 to 2 shift not stable
 

I am a new owner of a 1990 560 SEC. The trans shifts perfect when its cold. After warm-up,but not all the time,the 1 to 2 shift flairs to about 2 seconds and shifts very hard @2200 rpms,after this, the trans shifts up correctly.The fluid is beautiful bright red,smells normal, no burnt smell at all. I can sure use some help with this problem. Thank You in advance.
I followed the advice to check DIY section, I found something about getting oil on a unit on the passengers inner-fender, I sprayed some tire bright under the hood was this part of the problem?