Nissan Repair: nissan TD27 Automatic, nissan td27, accelerator pedal

Question
Hi,I have a  1990 TD27 4x4, the engine fires up and runs extremely well,when i put the auto into drive or 1 or 2 the engine stumbles and stalls-its set at around 1,000rpm-,it reverses with ease,when i do get going its as if im in 2nd gear,i can shift the auto back into 1st and back up to 2nd but it dosent feel like its going into 3rd or overdrive,there is tons of power but it feels as if the auto is going in and out of gear,ive adjusted the kickdown switch above the accelerator pedal and flushed the auto by removing the pipe at the oil cooler and putting at least 4litres of oil through the system.ive been told several different variations on how much oil it should have from 11 liters down to 3.5,at 10 liters the trans oil loves the driveway,so we went down to 7 then 5 and now we are at 3.5 liters with the same problem existing,is there a solenoid/computer or something i should replace,the rev counter dosent work either,(please give location of where to find the parts i need to replace if any, i dont have a diagram/manual),Thanks.

Answer
Don,

If the transmission is locked in second gear it is doing it because it senses an internal issue.  This keeps from harming the transmission further.  You need to get to a shop with a Nissan scanner to diagnose the problem.  Probably a system pressure issue of a bad servo in the valve body.  Now, if the tach does not work that needs to be corrected since the computer references vehicle speed and tach at the cluster.  I would check the wiring for the tach at the pickup on the engine as well as the fuse.  Remember, the TD is not generating a signal like a petrol engine.  nissantechinfo.com is a good source of information.  However, since yours is over ten years old you might have to go to the reference section of your local library.  Another option would be to check and see if there are any discussion groups in your area.