Thanks for asking this question -- it's been years since I heard
anyone say "granny gear" but thanks to your question and a touch of
Wild Turkey, the memories are coming back to me.

Back in the day -- back when men were MEN and trucks were TRUCKS -- my
friend Bob had a 48 GMC, ugly green with the curved windows on the
rear corners of the cab.

Bob's "little green truck" had a granny gear -- we called it "bulldog
gear."  When we would trek back into the Smoky Mountains and
surrounding areas, we often ran out of road.  Many a time Bob would
shove the little green truck into bulldog, pull out the hand throttle
(yes, it had a hand choke and hand throttle), we would get out of the
truck, he'd reach through the window to hold the steering wheel, and
we'd walk alongside the truck, watching for stumps, rocks , holes, and
the like while the truck pulled itself along with Bob steering through
the window.

The little green truck also had a spotlight mounted on the driver's
side windshield pillar with the control handle that aimed the
spotlight inside the truck.  We had somewhat limited funds at the time
-- being young lads who were employed delivering newspapers, cutting
grass, sacking groceries, and the like -- but we kept two $10 bills
rolled up and stashed inside the spotlight handle, just in case we
needed money.

One time something broke on the carb linkage and we fixed it -- no
kidding -- with a piece of wire cut from a coat hanger that we found
lying alongside the road.  Try that with today's truck.

Then there are all the old VW Beetles I owned . . .

I have been looking at some mid to late 80's F150's and F250's. The ones
that had manual transmissions were all 4 speeds where first gear is a
"granny gear". Is this normal? I would think that most of the transmission
would be geared more like a car and not have the granny gear.

Thanks
Ted