Thanks for all the good info. I'm not runing the governor on mine, so it never auto-shifts. I shift it just as I would a 2-speed truck axle, allowing slack time, for things to move properly. I figure that the TH400 is a lot easier on it, than if I was banging it and out, behind a 4-speed.
Actually, a lot of the time, I just leave it in overdrive, unless I'm going to back up. It makes the truck function much better, even around town. The low rear gears, with direct are great for getting it rolling, and the overdrive makes it much nicer, down the road.
I was surprised, and a little dissapointed, that 2nd and 3rd were so close together. I shouldn't have been, but I didn't actually figure the lower gear ratios, until I found the mentioned effect. Part of my reasoning for this project was the ability to drop half a gear, if I pulled into a hill.
It still makes a world of difference on the driveability of the truck. My only concern is the amount of load, on such a small unit, with that limited amout of lube, for heat disipation. After having replaced the defective seal, and re-routing the vent, I am no longer losing fluid.
Any thoughts on the fluid volume vs heat vs distance driven? I'm running synthetic 75w90 right now. The way I enclosed the front, it holds less than a quart. Adding capacity would be a substantial challenge, without totally changing my additions to the original unit.