Another Problem-4x4 humming (I think)

kxracer · Post by **kxracer** » Wed Aug 26, 2009 3:13 pm

Alright, ANOTHER problem. Today, it rained. I hadn't really gotten a good chance to take it out to test the 4x4, so I did. I drove through 2" deep mud, just enough to check and see if the 4x4 was working. It worked great, popped in, drove through, popped back out. I go and hop on the highway to head into town to wash it. Get about 1 mile down the road and I start to hear a humming noise. I was like WTF, so I started slowing down. The slower I went, the louder and slower it got (think bomb falling out of sky). When I get down to about 2 mph, I heard a quiet click noise, and the humming went away. I turned onto a gravel road and came to a stop. I put it back into 4x4, then into 2wd and this time backed up. I drove down the gravel road for a while, the road got a little muddy so I put it back into 4x4, and drove through it. When I got to the other side, I put it back into 2wd and backed up. I hopped back on the highway, drove 12 miles to the car wash, washed it, and hopped back on the highway to make the trek home. I went about 8 miles, and all of a sudden the sound came back. I stopped, and then took off again. This time it only went about 20 feet and the noise came back so I pulled over. I called my mom on the phone to tell her what was going on. She said to limp it home, so I did. It didn't make the sound the rest of the way home (5 miles). I just can't figure out why it stops make the noise, but then the noise mysteriously comes back. 4x4 is obviously not engaged because I can turn sharp without any popping, and the back tires are the only ones that spin. Sorry for the huge paragraph, but I am trying to be as detailed as possible. Thanks for any help.

Post by **HenryJ** » Wed Aug 26, 2009 3:24 pm

Hose off the underneath REALLY good. Reed suggests a sprinkler underneath may help.
Then you may need to put it up on jack stands and remove all the wheels to get all the mud out of the brakes and inner wheels.

It is really easy to get a tiny rock in a brake and it will make all sorts of terrible noises.
Funny how it only take a moment of fun to create a whole bunch of work. Play the game and you must pay the price.

kxracer · Post by **kxracer** » Wed Aug 26, 2009 4:06 pm

I will try that. I still don't see how the noise can go away and then come back after so many miles. It is such a weird noise, the first time it happened, I was so worried that I had completely broke it. I started to slow down, and the noise got so much louder/deeper/slower that it litterally sounded like a bomb falling out of the sky. Then the click and all was quiet. I sprayed under it pretty well at the car wash, but I will try again. Thanks

Post by **HenryJ** » Wed Aug 26, 2009 4:13 pm

Just spraying under there may not get it out. it may require pulling the wheel and loosening the rotor. That can be done by gently prying the pads to compress the caliper piston.

The smallest little pebble can really sound like a disaster, if it sneaks into the wrong place. They can pop loose and re wedge creating an intermittent condition.
That happened to my sisters Tacoma last time we went out. I had to pull her wheel at camp as she was really worried that she had ruined her truck. This was the first time she had really taken it offroad.

rlrnr53 · Post by **rlrnr53** » Wed Aug 26, 2009 4:25 pm

HJ, is it possible that his front axle is taking some time to disengage? I had the problem of my axle not wanting to disengage, but before I could check it out , it started working like it should. I've thought possobly that tne cable on the actuator may be hanging, but I haven't checked it out yet.

Post by **HenryJ** » Wed Aug 26, 2009 4:31 pm

That sure could be happening. He didn't mention that the light did not go out of 4x4.

F9K9 · Post by **F9K9** » Wed Aug 26, 2009 6:02 pm

kxracer wrote:.............4x4 is obviously not engaged because I can turn sharp without any popping, and the back tires are the only ones that spin.

This might need a little bit of clarification but, we know the OP's original intent.

You mess with mud and mud usually wins.

Roll up your sleeves and clean underneath your rig thoroughly. The sprinkler knocks off a lot but, I just use it to knock off most of the mud and to keep it from turning into cement. I then hit the coin wash. A pebble or stick can be anywhere under there. A pebble between the rotors and the shield sounds terrible. The rear shield for the rotor can be bent into rotor easily.

If, you insist in playing in water/mud then you will need to change the differential fluids if, you go deep.

Follow Brule's suggestions, in this case. It is going to be the cheapest route to go to troubleshoot your noise.

kxracer · Post by **kxracer** » Wed Aug 26, 2009 6:09 pm

Cool, thanks guys. The 4x4 light does go out, and the 2wd light comes on. I will try to tear into it Friday and clean it out. Will I be alright driving it like it is, or should I not? I have another vehicle I can drive. Thanks again

Post by **HenryJ** » Wed Aug 26, 2009 6:26 pm

I am not familiar with your terrain and the geology. A good hard rock can mess up a rotor fairly quickly.
You will have to be the judge. Another try with the hose might help it?

kxracer · Post by **kxracer** » Wed Aug 26, 2009 7:31 pm

HenryJ wrote:I am not familiar with your terrain and the geology. A good hard rock can mess up a rotor fairly quickly.
You will have to be the judge. Another try with the hose might help it?

yeah, I will drive it to school tomorrow (2 miles), and if it makes the noise again, I will drive my other truck to work (15 miles). I don't have to work friday, so I will climb under it and see if I can find anything. Thanks again.

JaVeRo · Post by **JaVeRo** » Thu Aug 27, 2009 7:52 pm

In two wheel drive your front driveshaft should not be turning. The easiest way of checking is to tear of about a foot of duct tape and stick one end to the front driveshaft. Pull forward about 10 feet, if the tape wrapped itself around the driveshaft then something is not disengaging.

If your front actuator is not disengaging, you won't feel any binding like you would in 4wd because the transfer case is not engaged. Your driveshaft will still be turning and that may be the noise you hear.

James

kxracer · Post by **kxracer** » Thu Aug 27, 2009 8:05 pm

JaVeRo wrote:In two wheel drive your front driveshaft should not be turning. The easiest way of checking is to tear of about a foot of duct tape and stick one end to the front driveshaft. Pull forward about 10 feet, if the tape wrapped itself around the driveshaft then something is not disengaging.

If your front actuator is not disengaging, you won't feel any binding like you would in 4wd because the transfer case is not engaged. Your driveshaft will still be turning and that may be the noise you hear.

James

Cool, thanks. I drove it today to school, and then to work, and it didn't make any noise. I wonder if wome water could have gotten into something it shouldn't? IDK, but when I clean the bottom tommorrow, I will try that duct tape idea.

kxracer · Post by **kxracer** » Sat Sep 12, 2009 1:53 pm

Alright, like I said, the noise went away. I did engage it into 4x4 today, and it is making the noise again. I did the duct tape-drive shaft thing, and my driveshaft did spin. What do you guys think is wrong, and any suggestions on how to fix it?

JaVeRo · Post by **JaVeRo** » Sat Sep 12, 2009 3:14 pm

Just for clarification, did the driveshaft keep spinning after you put the transfer case back in 2wd?

kxracer · Post by **kxracer** » Sat Sep 12, 2009 4:18 pm

JaVeRo wrote:Just for clarification, did the driveshaft keep spinning after you put the transfer case back in 2wd?

Yeah, I guess I wasn't very clear. The driveshaft spins while in 2wd, but the transfer case does disengage. Only the back wheels spin.

Post by **HenryJ** » Sat Sep 12, 2009 4:26 pm

Engine running, 2wd, trans in park. Reach under does the driveshaft turn by hand? With the transfercase in 2wd and the front differential disengaged it should turn freely.
If one or the other is engaged it will not.

Some things to check:
Sticky actuator cable, vacuum leaks in lines or diaphram, T-case switch.

kxracer · Post by **kxracer** » Sat Sep 12, 2009 5:18 pm

It spins freely with it like you said. Idk what to think.

Post by **HenryJ** » Sat Sep 12, 2009 5:42 pm

Does it still "humm"?
If you find it "Humming" check to see if the shaft is still free.

kxracer · Post by **kxracer** » Sat Sep 12, 2009 5:49 pm

HenryJ wrote:Does it still "humm"?
If you find it "Humming" check to see if the shaft is still free.

So, is it supposed to spin when the truck is in 2wd and driving forward? I stuck a piece of tape hanging freely on the driveshaft while it was in 2wd, and pulled forward about 5 feet. Then I got out and looked at the tape, and it was wrapped around the driveshaft. I thought the front driveshaft wasn't supposed to spin in 2wd. I'm so confused.

Post by **HenryJ** » Sat Sep 12, 2009 5:52 pm

It may rotate somewhat , but it will not be powered. Checking it by hand to see if it engaged is the only way to tell.

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Another Problem-4x4 humming (I think)

Another Problem-4x4 humming (I think)

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