here's how I spent my afternoon...
1989 pickup (22re/2wd)
working blind (how are you supposed to see behind the gauges to know what's what?)
I managed to unplug the two connections on the right side but couldn't get enough distance to pull the other two.
I also had no idea if the speedometer cable was clicked or screwed into place...
I manipulated the cable from inside the engine compartment...
Anyway, fussing & fudging & keeping it slow & easy... I managed to get the cluster loose...
Put the other cluster in, again "in the dark" with the cable... & thought it was in place... took the truck down the driveway & found: no speedometer...
Went inside. Ate dinner & did it all again... so far, so good.
(also: I did disconnect the oil sender BEFORE doing all this)

 

Check your firewall above your exhaust manifold. You should see your speedo cable. It should be held down around where it goes into the firewall. Unhook that and it will give you a little more room to pull the cluster forward.

 

that's exactly what I did do...

 

the oil pressure sending unit was $40 (& up) at the FLAPS... I decided I hadn't been to UPULLIT lately so... 2 bucks later I had the ONLY one in the entire yard... &, for further use... another gauge cluster (just in case)... & everything works as it should.