Tractor Repair: Case IH 895 faults, digital instrument cluster, torque amplifier

Question
Hi All,
A friend of mine has recently purchased a 1993 Case IH 895 XL, he bought it as seen with a siezed engine , now a replacement engine has been fitted it runs and drives ok but when the switch for the torque amplifier is operated nothing happens can you give me some pointers on how to fault find this system? Also the tractor has a digital dash board, this lights up and shows engine rpm but the pto rpm display doesnt display anything when the pto is running. Is there a pto speed sensor I could check, how, and where is it located?
Any help is appreciated as I have not worked on IH tractors much  

Answer
Hello,

  First check all the fuses, and if they are all OK, then check the torque amplifier switch, and the clutch pedal switch.  Look for bad wires or poor connections, or connectors that are not plugged in from when the engine was replaced.  I have seen the ground wire on top of the transmission not hooked up a few times.  If these are all OK, drain the transmission oil and remove the bottom cover.  Check the torque amplifier shift solenoid, and check the o-rings on the solenoid and oil tube.  

  I can't find any parts listing for a pto speed sensor, only a ground speed and engine rpm sensor.  The instrument cluster is programmed to calculate pto speed from the engine speed.  That's how the 66 and 86 series IH tractors displayed pto speed also.  So if it won't display any pto speed, there's probably something wrong with the digital instrument cluster.

                            Good luck,

                             Arnie