Isuzu Repair: 4x4 Isuzu Trooper 1988 does not work, excessive torque, light mud

Question
QUESTION: Hi, I am trying to fix my 4x4, 4cyl,A/T, A/C, Trooper complitely. I got it with a missed elect. trans. control unit which now I had bought it and installed. The 4x4 light turns on when the lever is positioned on but my trooper does not run fast, maybe just get a few 10 miles/h. I realy do not know what would be the problem.
Please reply to my e-mail: alberto@fis.cinvestav.mx

ANSWER: Well if the light comes on Alberto but the 4x4 does not work then your 4 wheel drive switching solenoid could be to blame. Or the vacuum switch motor if so equipped on this model as well as the indicator switch. Let me know if this does not sound right okay?

---------- FOLLOW-UP ----------

QUESTION: Hi, Daniel,
My 4x4 trooper has a lever for 2H, 4H and 4L. I understand that when my trooper is at 2H is at back traction and run very fast at Drive position.
But what about 4H and 4L lever position. How must be the trooper behavior at speed? When care I have to have when I want to change through these tree positions? Or I do not have to worry.  I do not have a user manual. Do you have one or can tell me how to get one in English? I will look at the solenoid and to the vacuum switch motor (where should be it located?)
Best regards.  

Answer
It should be located just above the left axle-shaft Alberto. Also 4-low should only be used at very very low speeds and when excessive torque and traction is needed. 4-high can be used for a little extra traction such as snow and or rain and light mud. I hope this helps you if not let me know and I am more than happy to help.