92 740 GL wagon shifting problem

It is the wagon version with the turbo engine. At first I thought it
was not ever shifting into third gear, but I think it actually is.
Must be, as I can select 2nd while in third, and the motor revs up a
lot. To do about 65 mph, the engine turns abt 4000 RPM. So I crawl
along at 55 no the freeway. So I am thinking now that the overdrive
is just not ever kicking in. I have tried going up as high as 4500 RPM
and it still did not shift into OD. The OD disable button is working.
Push it once, the arrow on the inst. cluster comes on; push again, the
arrow goes off. Could the switch and arrow indicator be working, but
the electrical signal is not actually getting to the tranny? How to
test this (I don't have a wiring diagram for this car)? If the
kickdown cable is misadjusted, would it keep the OD from kicking in?

 

One, check the OD relay. Easily resolderable and a cheap fix. Next, pull
away the shift boot and check the wiring for the OD switch. There is a split
at the base of the shifter that eventually wears away the wires' insulation
to the OD (pull up on the shift knob to get it off, but be careful, as there
is not much leeway in wire lenth to the switch and it'll rip the wires off
if you yank it). I rewired my switch, and resoldered the relay in one shot.
Took 45 minutes and no problems since.
btw: search brickboard.com for pics and instructions on this.

Cheers.