Hello SON,
Since winter is here I thought I would share my experience with switching transmission fluid. I was previously running Redline MT90 on my 240 which is daily driven. I went through horrible second gear grinds for two winters. As of three weeks ago I switched to GM Synchromesh.
**Please note that these experiences are based on my 240 and normal driving practices. By normal I mean when I am driving to work and not driving the car hard. I am making shifts in an around 2700 to 3000rpm. I realize that others may have different experiences but I figure this information would be of value to those looking to switch fluids for this winter.
Here are my experiences in reference to temperature (degrees celcius).
15 C - Shifts feel similar to that of with Redline. Smooth almost like a summer day.
10 C - Shifts feel ever so slightly smoother with the Synchromesh but not enough of a difference unless you pay super close attention. In my case I was being as critical for my own information.
5 C - Shifts are now noticeably smoother from a cold start with Synchromesh. During the 2 years of using Redline I would have to begin double clutching at this point to avoid grinds going into 2nd. The grinds occur within the first 20 minutes or so of driving and beyond that I am okay. I am shifting without double clutching with the Synchromesh
0 C - Shifts remain smooth as in 5C temperature. Still shifting without double clutching. During the 2 years I would experience and increased amount of grinds (in reference to 5C weather) mainly with into 2nd and once in a great while 3rd.
-3 C (as of this morning) - Shifts remain as smooth as in 5C. No noticeable difference in smoothness. Still shifting without double clutching. This is the easiest I’ve been able to get into 2nd in cold weather since I bought the 240.
I will add my experiences as the temperature continues to drop.