I once again come to the Dodge gods for assistance. I have a '98 5.2L SLT 165K on the clock. I love my rig. Engine burns some oil but hey its got 165K on it.

About 2 or so years ago due to some angered driving I blew a transmission. Due to lack of funds it sat for about a year before we could begin working on it. To shorten the story we put 3 transmissions in it. One junk yard one, and 2 re-built. Shortly after putting in the last trans the mechanic said the speed sensor in the rear end needed to be replaced as it was causing the trans to hold a gear, and the ABS and Brake lights. So we replaced it. About 1 month after that a faint whining could be heard. When under load. I dismissed it as glad to finally have a running rig again. Well the whining got worse and about 2 weeks after first hearing it took it back to the mechanic who put in the trans. He drove it and said it was a rear-end. He also stated it could be driven indefinately like that it would just get louder. So I continued to drive. Let me add that I drive approx 300 miles approx to work. 150 miles up, then gone for a week, and 150 back. ALL HIGHWAY.

So after this last winter the noise seemed to change and become a grinding. Out of fear of a major failure at highway speeds I traded vehicles with my dad to get to work.

Last week we decided to have a junkyard rearend put in. A different mechanic looked at it from the one who put in the trans. He said its not the rear end that the noise sounds like its from the front half of the car, possibly the transfer case, or wheel bearings. He can not hear any drivetrain noise when on the rack.

So now that you have the history, here is what I think, and need assistance with.
I do think the rear end is acting up as the the whining changes when the car is swerved. Could the new sensor they put in have failed throwing pieces into the rear end, or not a good seal and the rear end oil leaked out. I was told by another mechanic that I shouldn't open the rear end to change the oil since it has so many miles on it, that anything floating around in there could be adding to the lubrication factor of the oil. I call BS but since this isn't my area of expertiese I defer to you guys. I'm thinking opening it up cleaning it out with some parts cleaner, and putting some oil back in there will help more than hurt. Thoughts on this part?

The second noise, the "grinding", is the transfer case. Its peak noise is between 50-65 and its so loud I can actually feel it behind the pedals thru the floor. Could the oil have gotten so thin that it actually seeped out the seals and left me with a dry transfer case? I never noticed any fluid on the driveway but 300 miles at highway speeds I wonder if I even would. So same question as the rear end, can I pull the drain plug on the trans case, flush it with parts cleaner, let it dry and refill it?

I know its a long post. Money is really tight and I want to keep this truck running for as cheap as possible.

Thanks very much guys in advance for your assistance!!!

 

you can always change the lubricant, the only time it is not suggested is SWITCHING from dino to full synthetic motor oil on a high mileage engine, change the diff fluid front and rear and the t-case fluid, make sure you add friction modifier to the diff if you have a limited slip (trac-lock). also the whirring sound is most likely a front hub/wheel bearing going out and that will change when you turn as the forces acting on it shift across the vehicle.

BTW: i believe the t-case uses the same ATF+3 (i think in 98)that the transmission does,

 

How can I find out if I have the limited slip diff? I have no clue. Are the front hubs easy to do, or can I just replace bearings or what?

Thanks..

 

Raise the truck from the rear and spin the rear tires. If they both spin in the same direction,then you are lsd. Has far as your other noise. I have found the large bearing inside the overdrive unit will be pitted and cause the same type of noise. But first i would do like shrpshtr325 had said, change the oil in front and rear diff and transfer case too. Front hubs are easy to replace, you either need a 35mm or 36mm socket or a 15mm socket.

 

This is the correct fix.

Sounds like a U-joint on the driveline but this is a Hummmmmm sound and vibration and not a whine sound that I would say is a Pinion bearing. Did you replace the entire rear end or only the differential?

With no weight on the parts the truck could be "hiding the sounds".


Swerving and no sound makes me thing a wheel bearing or a pinion.

I really doubt it. You can pull the sensor in like 5 minutes:


Could have but you should notice dripping marks on the driveway.
This is the biggest bunch of BS thats out in the mechanical world. Change that lubricant!

Don't do this as you could cause adverse problems not using the correct cleaners. Replace the fluid and place 5oz of Friction Modifier in then top it off with 80W-90 gear oil (GL-5 Hypoid rated) if you have a Limited slip and just 80W-90 gear oil (GL-5 Hypoid rated) with an open rear end. If both wheels turn with the rear end off the ground then it's LS and if it is open gearing then one wheel should turn one way and the other wheel will turn the reverse way.

Try and get some passenger friends to help you narrow down where it is coming from through the floor.

Thanks for all the details, and your welcome.

 

Thanks guys. There are two different sounds, at least it sounds like it to me. One whining that appears to be coming from the rear. The other I can only describe it as a loud metallic vibration that I can feel in the floor of the truck under the pedals. Now that sound is at speed, 50-65ish. If I grab the transfer case handle I can feel the vibration in there. Now at slow speeds, creeping, or brake off idle movement, it definately sounds like a metal to metal gear noise from the center to front portion of the car.

I'm out of town right now, I get home late Sunday night and I'm formulating my plan of attack for when I get home.

BTW.. We never put the rear end in, the mechanic said he didn't think that was the problem so we didn't do it. I guess when I get the rear cover off, I can take some pics for you guys and see if you see anything out of the ordinary.

Thanks..

 

Take some good pictures!


The other thing you can do is remove the front drive shaft (first mark the yokes and drive shaft so that it can be installed back into is OEM position) and take it for a drive. If there is no sound then start looking at the front.

Still sounding then you could replace front drive shaft and remove the rear drive shaft then place it in 4 WD (HI) and use the front end to pull it to see if you can diagnose if it's the rear diff? I would think that if everything is the same then transfer case, then differentials, then pinion.

 

Rear diffs are a lot like Women... they will whine a lot before finally leaving you.

With that said, always cheaper to fix than replace. That's why breast enlargements are so popular.

IndyDurango

 

Amen brother!

 

lol, you make a VERY good point there indy