904 vs 999

318willrun said

It's in a '82 D150, slant six. Not sure it the truck got a tighter converter, but two things I do not like about the truck lock ups:

1. very unforgiving when going to reverse or drive, idle has to be low or it's more of a "bang" into gear rather than a "shift" into gear
2. Once locked up around 45 mph, it lugs the engine on uphill's or such.

Transmission is in excellent working condition.

Click to expand...

As to #1;
I'm gonna go out on a limb here and say, the engine has too much Idle Power is why it bangs. Take some Idle-Timing away, and see what happens. It could be other, but this is the easiest test.

As to #2
the trans should NOT be going into LU that early, the RPM is way too low.
Is the trans original to the truck? Or
Has the rear gear ratio been changed
or really tall tires installed,
cuz either of those are gonna affect the governor.
As will the KD adjustment and the line-pressure.
I would be hesitant to blame the one specific model or year for these annoying characteristics.