I have used the house brand from O'Reilly. I currently am using Mobil One Synthetic (O'Reilly, also). Some use Valvoline Synthetic, Amsoil, or Schaeffer's.

 

The descriptions of what the VB does are good -- it controls the speed of the transistions between gears and the amount of pressure on the clutches. Faster shifts & more holding pressure = less heat and less wear on the clutch material, which = a longer lasting transmission. The premise that nice smooth shifts are "good" is just flat wrong. Nice, firm, short shifts are what you want. As you know, I went with the TransGo kit and am quite happy with it. When you do this, be sure to get your tunes matched to the "new" tranny or it just won't feel right. When I first did mine, I waited to send off my tuner and it seemed like the shifts were better in stock mode than in any of the performance tunes. When they match, it's a whole different truck!! You won't believe the difference -- I'm still kicking myself for not doing the trans mods sooner.

On the fluid, I'm a firm believer in syns, so I went Mobil1 Mercon V. It should last about twice as long as dino, especially after these mods. Keep it cool, and send a sample to Blackstone at 30k (the normal change interval) and see how it's doing. That's what I'll be doing. Why throw away $100 worth of syn fluid when you don't need to ($5.50/qt x 18qts)??

 

Well thanks for all the replies guys. So If synth is the best way to go who has the Cheapest Synth around? Also how many Quarts does the trans hold?

 

Valvoline Synythetic Mercon V was $4.19 a qt. at NAPA this past April when I did a flush. You will need twenty qts. to do the engine running flush. 2 qts are wasted to insure all clean fluid when done. Read the write up by Mark Kolvalsky. Tranny Flush Click Here

 

You might want to check on the Valvoline Synthetic at O'Reilly. It was posted that they had it for $3.99/qt, unless it went up.

 

Thanks so much I will!

 

Honestly I would've gone with the Valvoline Syn Mecon V had I seen that it was a $1.50 cheaper than Mobil1 per quart. I used to run their dino engine oil and liked it a lot. The amount you save on 20 quarts of fluid will pay for your Blackstone analysis in 30k miles...