I have a 91 Loyale wagon (5speed, push button 4wd, EA82 SPFI), and a few days ago it started making a grinding noise that gets worse with rotational speed, so at freeway speeds it almost sounds like a helicopter taking off. I assumed it was another axle blow-out, as I've gone through 3 of them this summer and this one had a cracked boot for the last thousand or so miles, so I replaced the culprit axle (this time with an axle from MWE).
However, the noise did not go away. The next day it rained/snowed/iced and when I went to pop it into 4x4, nothing happened. 4x4 had been working great the previous week (before the sound came). It also makes some sense now that the sound seems like it is coming from the rear - could it be the rear differential constantly trying to engage and grinding a bit?
Today I also realized that my heater is only blowing out of the dash no matter what setting its on, no defrost vents, no floor vents. So that leads me to believe that I'm looking at a vaccum system issue. My main question is: Is the 4x4 engagement on my car vaccum controlled, so are these two problems stemming from the same source?
Am I on the right track with the vaccum system? And where would you start on troubleshooting the system?
Edited by SLAVAGE, 05 December 2013 - 07:44 PM.