Planning on changing the fluid and filter in the transmission. I want this thing to last as long as possible, so I was tossing around the idea of installing the TransGo kit for the 4L60E. Does anyone have experience with it? Will it prolong life? Also, I've always believed flushing was a big no-no on automatics. Am I correct to just drain and refill with Royal purple ATF?

As for the diff, I'm planning on using Royal Purple 75w90.

 

Good Day! You did'nt mention how many miles you have on your unit, so that would be a factor as whether or not to put shift kit in. Over 150k,I wouldn't recommend it unless you know that the trans had been faithfully serviced by the prior owner. As for going with the Royal purple,fine but you need to COMPLETLY flush out the standard fluid for best results. As for the diff:closly inspect the condition of the cover,as these rust out! Replacements are available at NAPA for only$12 (incl gaskt) Clean it with brake cleaner and then prime & paint the exterior and install-it'll be the last one you'll have to put on!