I had an issue one morning on the freeway heading to work, this strange howl suddenly appeared...I was cruising along at 70mph when this occurred....my first thought was that it was coming from the differential...the howling was present later after hitting 30 mph...I looked at YouTube videos and some suggested the IAC, which could howl....and the videos showed someone disconnecting the IAC and the howling was present, but unlike what I was hearing...I replaced the IAC with a Motorcraft as I was reading reviews on aftermarket units..this did nothing..howling still there..I took my 1995 Ranger into a local auto repair by me and they put the truck on jacks and ran it through all gears and was told it sounded like the transmission, which they don’t service....I ended up taking it to an independent auto repair shop...this mechanic hopped in, took it for a drive and told me, “ ah yeah, I know what that is, I can hear the howling!”.... so I made an appointment...they had the truck a week as they were overbooked...I received the truck back and the howling was still there...I had a trip scheduled for Calif the following week...oh, this is a 1995 Ranger Ex. cab 4x2 with 184,000 miles.... my trip to California was ok, no issues...the howling was present from 30 mph up to 85 mph....I got home and the noise was worse...I took it back to the transmission repair shop as it had a one year parts/labor ....Again, this different mechanic took it for a spin, with me sitting next to him....”oh yeah...blah blah blah...They scheduled me a week out which was no problem...so I did some troubleshooting on my own, I have never replaced any of the bearings on the tensioners, so I disconnected the surpentine belt and went around the block, the noise was still there...so the following week it went back in the shop, they told me as soon as they found the issue they’d call me.....it wasn’t but a few hours when the shop called me and told me what the issue was...IT WAS THE FRONT U JOINT...wtf!! When the Ranger was in the first time I had a new clutch put in as it was nearing the 90 thousand mile era...lol....all the needle bearings were gone in the u joint and the howling was from the joint itself rubbing up against the rubbers on the cups!!!!!! I questioned them about this issue and why it wasn’t caught the first time, they had to remove the driveshaft...I’ve done u joints on many vehicles in my life and when the needle bearings completely dissentigrate, there is some sort of ‘slop’....anyway, this complete job ended up costing about $1650.00!!

 

Hello 95WhackyRanger
I know this post is a few years old but I am having the same issue and trying to do some research on it. I have had this howling for about a year, been working on kids cars, no time for my own, anyway, I am getting into it now and I thought maybe wheel bearings but they seem solid. Did them replacing your U joint fix the howling? There was no clunking or slop in the u joint connection? I appreciate the response!