because the gear he has and a stock stroker,my truck will barely accelerate with 2k on the highway in od,i didnt think the E40D was that much different then the zf
Let your truck tell you how fast you can pull the load in OD with the five speed. If it pulls down just drop a gear and keep on going. You know it will pull down on hills. Just keep you RPM at around 1600 to 1800 and above when pulling.
I have on flat. Around my area and on back roads, I keep in out of OD, but on the Highway I use OD if it's flat. If I need the power to pass or go up hill, I just take it out of OD.