Hi All,

I've searched everywhere and can't seem to find any answer for this problem. The truck had quite a few issues when I bought it but this one I can't seem to find or repair.

The problem is a low grade moaning noise when I reach 30 Kph that peaks at about 60. It seems to be coming from the front near the middle and I'm not sure if I can feel it through the floorboards or if I'm hallucinating now. If I let off the gas the noise seems to get louder, mostly because it isn't drowned out anymore. If I shift to neutral while it is happening it doesn't go away. If I turn slightly to the left it disappears completely.

The work I've done:
Replaced front differential
Replaced front drivers CV (chewed to pieces)
Verified front passengers CV good
Replaced both sets of front wheel bearings
Filled front hubs with Red'n'Tacky
Replaced front propshaft after greasing it very well
Replaced all 3 ball joints in the steering (no play now)
Replaced starter
Replaced oil in front/rear/center diffs, no shavings
Verified all oil/fluids topped up
Rewired improperly installed stereo
Verified ground wiring in engine compartment
Checked front brakes, not bad but need to be replaced


Ideas?? I'm not afraid of hard work and can check/replace near anything as I have the manual and tools. Other than the moaning, the truck runs quiet and smooth.

My thoughts:
Brakes?
Steering pump?

Thanks in advance,

Anna

 

The transfer case on a 97 is gear driven and makes a humming noise like the one you are describing. It sits right behind the transmission and is located right in the middle of your truck. I didn't read anything regarding the transfer case on your list but you may want to check the fluid level. There is a drain plug and a fill plug right next to the parking brake drum. The drain plug is magnetic, if you replace the fluid check for metal shavings. The amount of shavings if any will give you some indication of any damage. When replacing the fluid use a high grade synthetic. Royal Purple 80-120 gear oil is what I put in mine if I remember correctly. Do a search for "transfer case" and you should find plenty of info. Good luck.

 

Might also want to check the wheel bearings.. Noise can travel thru the frame and appear in weird places.. The turn left sound goes away suggests a wheel bearing..

Aren't there four ball joints in the steering ?

John

 

The oil in the transfer case has been changed, no shavings or chunks in it. I replaced it with the factory recommended oil weight but am willing to do it again with a heavier weight. If it's the transfer case, should this hum be loud enough to hear with the stereo on?

The wheel bearings in the front have been done, I was thinking I should do the rear but haven't yet (though the wheels don't feel wobbly). I'll likely do them anyway as I'm not sure what kind of service place the PO was taking the truck to. The same place that told him they'd replaced all of the ball joints when what they really did was clean them it looks like. And sorry, I meant 4 joints, not sure why I said 3!

 

I figured it was a typo..

Hard to miss the last one when you've changed three already..

I'm in the middle of a suspension restore on mine as well...

I'm doing everything...Every bushing and joint will be refreshed...

It's dirty work, I'm telling you... Dirty greasy nasty work...

I like it...

Then I'm going to take it out and climb something with it..

Oh, Check the engine mounts.. I had one on a Ford Focus moan for years till It got bad enough to change.. It would quit when turning as well..Didn't think about that till just now...

John

 

Interestingly the dirtiest, greasiest job I have done so far is the starter. Everything else was dirty but not that bad, I actually had to throw out my clothes after changing the starter. I'd clean the engine but I don't know what would start leaking if I did so I'm going to wait on that.

I'll check the engine mounts later today, it didn't really occur to me....everything else went catastrophically wrong and, with my luck, a bad engine mount should have caused my engine to actually smack into the ground or swing wildly and take out my garage or something.

Personally I would just like to drive the truck I've owned for almost a year....I can be patient about climbing something with it LOL

Anna

 

In addition to upping the transfer case to thicker oil, I added this LUBEGARD Gear Fluid Supplement and heard some noise reduction. D1 178K. As for hearing with stereo on, depends on what you found on the oldies station.... some just sound so much better cranked up.

 

If your putting it in neutral it's not engine driven if it remains high. A power steering pump whine would fall in pitch with rpm drop. So it's road driven. How did you verify the passenger side CV? Slight left turn would roll more of the vehicles weight and momentum on that wheel.......maybe tighten up a worn CV. The other side shattered right.......

 

I pulled the CV when I did the wheel bearings, cleaned it up and inspected for wear/cracking/looseness etc. It looked exactly the same as the new one I put in the drivers side.

I'm going to install a new exhaust manifold this weekend as well as replacing the rear wheel bearings on both sides. I suppose I'll also drain the transfer case and put in the thicker oil too. Might as well make a party of it!

Anna

 

While you're in there you might check the engine mounts and the transmission mounts. It is possible the rubber has deteriorated and there is metal to metal contact causing the sound to propagate through the frame. (sorry for the big words, I don't know what came over me).