Welcome to TRS
Hitting a racoon?
Pretty sure that wouldn't effect automatic transmission unless it bent shift linkage or knocked off trans cooler hose, either of which could be repaired without a rebuild or new trans.
If shifter is stuck in 2nd then trans is fine, linkage is bent
You will have an A4LD automatic transmission in an '87 Ranger
Automatic transmissions will have a bell housing that matches the engine size it was made for.
And the bell housing is part of the front pump assembly so can't be changed without a total tear down of transmission.
So first thing to check is that the used/new A4LD is from a 2.9l engine, 2.3l or 3.0l trans won't bolt up to your 2.9l.
4.0l engines used the same block as 2.9l, so would match up
Also needs to be 2WD transmission, 4WD have different tail shafts and won't work for you.
From 1986 to mid-'88 the A4LD had electric solenoid TCC(torque converter control), computer would lock torque converter once you were moving for better power and MPG(no slipping), then unlock it for coasting and stopping.
In mid-'88 Ford added 3-4 electric shift solenoid, OD-overdrive shift was now controlled by the computer.
Your '87 computer wouldn't have this 3-4 shift control in its software.
A4LD was used with TCC and 3-4 shift solenoids until 1994, in 1995 more solenoids were added for full shift control, and the A4LD was renamed 4R44E, or 4R55E(4.0l)
The 1986 to 1988 A4LD from a 2.9l should be plug and play, look on the passenger side for a 2 wire connector, that means TCC only which is what you have now, look at yours to confirm.
In later '88 there will be a 3 wire connector, for TCC and 3-4 shift
That was use until 1994.
You can use 1988-1994 A4LD from 2.9l or 4.0l, 4.0l was a better A4LD than 2.9l.
But you would need to add your own OD switch, it is just a ground so very very easy to add a ground switch to the cab, also gives you more control of when overdrive comes on and goes off.
Buying a used automatic transmission is often a bad idea, lol, unless you plan on rebuilding it, because the last A4LD would have been made 22 years ago, so there will be no "low milers" around, people don't usually pull out working automatics to sell them.
Wrecking yard A4LDs will be long gone.
When there is a problem, like you have, people do what you are doing, swap out the bad trans for a working one, and some sell the bad trans, AS IS, so you could just be buying someone else's problem
heads up
Welcome Visitor! Please take a few seconds and 
