# 4wd drive train noise



## mathmonger (Dec 27, 2012)

I have a Dodge Ram 1500. 2005. 120k miles. 6 speed manual. 4wd. There is a grumbling sound somewhere in the drive train. I think maybe a bearing in the front differential. How can I confirm that?


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## daveb1 (Jan 15, 2010)

Do you have manual or automatic front hubs? If one hub is locked and one is not there can be a grumbling sound.


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## Windows on Wash (Aug 30, 2011)

+1

Hub bearings are also known to go bad too. Check there.


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## 1acre (Oct 5, 2015)

if you think it is the differential, you can pull the plug and drain the oil. The diff plug usually has a magnet on it and you can see if there are any pieces of metal. before you pull the drain plug, make sure you can break the bolt used to fill the diff with oil. 

if the noise is a grumbling sound that happens once you get some speed and then let off the accelerator, the first thing I would check are the driveshaft u joints. When was the last time they were greased? 

If the noise happens when you turn, try to listen to what side it is coming from, as it is most likely a hub bearing. 

if all that fails, you can check to see if the backlash of the diff is excessively loose or tight by jacking up the wheels and moving side to side. Not very scientific, and you'd probably already know if it was that bad. the pinion in the diff can be checked if it is loose by taking off the drive shaft, grabbing the flange and pushing/pulling on it, there should be no movement. 

I'd start with driveshaft u joints, then hub bearings.


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## Brainbucket (Mar 30, 2015)

Put it on a lift and have someone put in drive with wheels off the ground. Go to each corner (Wheel) and listen for noise. Dodges usually don't have magnetic drain plugs in the rear ends. :vs_coffee:


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## ukrkoz (Dec 31, 2010)

When were the three fluids changed? Front diff, rear diff, and transfer case?


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## mathmonger (Dec 27, 2012)

I don't really understand how the hubs work. On my old Suzuki Sidekick, there were manual things you had to turn on each of the front wheels if you wanted to switch into 4wd. The Ram doesn't have that. Do the hubs disengage automatically or do the axles just spin all the time? I dunno. 

I did feel a little play in the right front wheel. I was sure that was causing the noise. My mechanic thought so too, so he changed it out. The noise was still there, so he changed it again, thinking he got a bad part. Running the truck on the lift and listening with a stethoscope have been inconclusive. 

There is no play in the U-joints. And I don't think those even have a fitting for a grease gun. 

There is some play where both the front half axles go into the differential. I don't know if that is normal or not.


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## 1acre (Oct 5, 2015)

you're not giving us much to hang our hat on. When are you hearing the noise? turning? accelerating? decelerating? where is it coming from? just the front? can you hear passenger or driver side? towards the motor or more underneath you? 

I think you've focused so much on the front diff, in your mind it can't be anything else but the front diff. There are other things that are usually easy to do that you should check first. Like greasing your u joints. Yes, u joints take grease. It looks like dodge used some type of spicer joints on your model year. 

What did your mechanic change out? the problem with putting it on the lift is sometimes things need to be under load for you to be able to tell what is wrong.


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## ddawg16 (Aug 15, 2011)

Where are you located?

If you have an Amco near you, take it there. They are real good about telling you what the problem is for free. It's drivetrain related so it's right up their alley....


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## mathmonger (Dec 27, 2012)

Noise is proportional to vehicle speed. Doesn't matter if I'm accelerating or coasting. Turning doesn't affect it, except maybe in extreme right turn it goes away for a split second. I can't really tell which side, but I kind of feel the vibration in the steering wheel. Sometimes the grumble morphs into a howl. 

The mechanic changed the front right bearing. Definitely loose and had to be done, but not source of noise. 

I'll check into greasing u joints. And Aamco is a good thought too.


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## mathmonger (Dec 27, 2012)

Fluids have all been changed anout a year ago according to the guy who sold me the truck. Fluids seemed in good condition.


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## ddawg16 (Aug 15, 2011)

Put it in neutral....parking brake on

Crawl underneath and grab the front drive and wiggle it. It should be stiff.

Another way to test....put it in park....lock the front in 4Wd....then have someone rock the truck back and forth while watching the driveshaft.

Next option...Amco 

Since you can't tell which side....sort of sounds like your gears or diff bearings. Gears tend to have a howl to them.....bearing grind


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## ukrkoz (Dec 31, 2010)

mathmonger said:


> Fluids have all been changed anout a year ago according to the guy who sold me the truck. Fluids seemed in good condition.



And how reliable is that source???
How do *you *KNOW fluids are in good condition AND proper level? Diff will howl when low on fluid so will t-case.

But I do not think it's actually related to drive train. Sounds like bad hub bearing or bad U-joint. 

Still, make sure fluids are tip top.
Seller said.... Rrright. Unless he's your best pal or family member.


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## mathmonger (Dec 27, 2012)

No, the seller said he got everything changed. It seemed like overkill for a truck he was just going to sell, so I was very skeptical. I checked all the fluids personally. They were all full and looked like they were brand new, so I believe him. He was actually pretty clueless about the truck and said he always took it to Meineke.


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## ukrkoz (Dec 31, 2010)

OK, so the most obvious problem is not there. It is not really that hard to do fluid changes on trucks, just ability to get to all the plugs and good way to refill. Easy.
Meineke is muffler place far as I know. Midas is brakes. Of course they do side jobs yet... Expecting some level of complex expertise from them is rather far fetched.
Buddy has that small Dodge pickup, he has growling noise from rear end in turns in reverse. He knows it's diff but that truck is rebuilt title and otherwise functions well for several years now, so he keeps driving it.


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## Brainbucket (Mar 30, 2015)

Ok. When is noise more prominent? Is it louder with more speed? Is it louder when you turn right or left? Is it louder when under load (giving it gas in gear while rolling)? When you are giving it gas in gear ( while you are rolling) then you let off, is it louder. Does the noise pitch change with the accelerator pedal change? Also does the noise pitch change when the road changes? What I mean is when the road goes from concrete to asphalt? (That's tires as bearings don't care what the road is) When a seller changes all the fluids before a sale, they are generally trying to hide/repair/ a problem unless you have a good person who just wants to make sure you get a good truck. But yet there is that noise..... :vs_worry:


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## mathmonger (Dec 27, 2012)

I can feel a little wiggle in the driveshaft where it goes into the transfer case. Geez, I wish I had something to compare it to! Could I just pull out the drive shaft and drive around like that? Or would that cause horrible things to happen?


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## Brainbucket (Mar 30, 2015)

I'm looking at the transfer case pic and I need to know if it is a 5.7 gas or a 5.9 diesel. If the drive shaft bolts onto a flange on the transfer case then you can remove the shaft and drive the truck. If the drive shaft 'slips' out of the transfer case then no. Now a 2 piece drive shaft has a carrier bearing that will make you pull out your hair trying to find a noise but a truck on a lift and a mechanics stethoscope will solve your problems. :vs_coffee: Sounds like that's what you need to do.:vs_cool:


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## mathmonger (Dec 27, 2012)

Soooo. I took it into Aamco. The guy tells me that he can hear the noise change when he turns and he had three guys check it and he ran it on the lift and he is sure the noise is from the front right. This is the one that I just changed twice. He wanted to take it apart to check everything out, so I let him do that. He calls me up and says that in addition to taking the right side apart, he took the left side apart as well. Why did he do that if the noise was coming from the right? No clue. Now he tells me both sides are grinding, but the left is worse. He says the bearing my guy put in is Chinese junk. So he wants to charge me a thousand bucks to change both bearings and put in Moogs. So basically that free diagnostic service is a get what you pay for type of situation.


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## cjm94 (Sep 25, 2011)

Sounds like they guessed at what side it was from and were wrong...so now both sides are bad.


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