W124 E420 Slipping/Flairing in 2-3 upshift

[rmasteller]

Hi. Sorry if this is redundant, but I tried searching and there are too many search term combinations to use! (Transmission, Trans, Tranny, Rev, Slip, Flair, W124, E300, 300E, E420, 400E, Shift, Upshift, etc., etc.)

My car, a 1994 E420 (no mods) w/ 85,000 miles, will occassionally rev up 1,000 to 1,500 extra RPM druing a 2nd to 3rd shift during easy acceleration. It then grabs and the RPM drop back down to normal. This might not happen for several days, but then it might happen several times in one day or even one trip. It does not appear to be relative to the car/engine being cold or warm as it's happened under both conditions. I have noticed that it has never happened under brisk acceleration. Other shifts can sometimes be more firm then I think they should be, but not so much that I've had anything done but an additional transmission service back at 60,000, which did nothing for the firm shifting.

I checked the transmission fluid per the owners manual and it was full up to the proper mark for an engine at operating temp. I often read that one can find problems by smelling the transmission fluid, but I don't know what smells right or wrong.

What actions can I take to narrow down my problem so I can speak intelligently with the Service Advisor at the Dealership.

The car is still covered under Starmark Warranty.

Thanks,