Ive been using Pennzoil Synchromesh in my Rangers 5 speed which calls for ATF with no problems, I've used it twice in the past 5k miles, changing it at 2k intervals to flush out the original stuff that was in there from 2001. There is almost no metal particles on the drain plug and it shifts good, but in the cold especially in the mornings it is sluggish to shift until I drive for a lil bit and it warms up. While it isnt the recommended fluid, should I keep using it, or shoudl iI go with another fluid such as Redline MTL, or D4, of which ive both heard good about on here. Is it possible that the synchromesh and the MTL, if i decide to use it, is too thick for the M5OD? Synchromesh Cst is 9.3 while Redline MTL is around 10.5