Front end noise - 4x4 related? 1999 Sierra 1500 4x4 5 Speed

[bisakm6]

Hello everyone,

New to the forum and would really appreciate your help. I have a 1999 GMC Sierra 1500 4x4 5 Speed manual w/ manual transfer case. We recently had a snow storm and I used the 4x4 for the first time in a little bit. The next day I noticed a bad front end noise. It's not a whining but rather a low growling/grinding noise. I did help pull people out during the snow storm and wondering if that had anything to do with it. I tested it today and if I put it in 4 hi, the noise is louder. Some times that I have put it back to 2wd it still feels engaged in 4x4 (going off of the turning test). I put the T-case in neutral and back to 2wd and it does not stay engaged in 4x4, however the front end noise is still there. I checked for front end wheel bearings and the left side has play in it for sure. If I spin the left wheel off the ground it's noticeably louder than the right.

 

Could it be a wheel bearing? How could it make a significant noise within 1 day?

 

Actuator motor?

 

Any ideas/thoughts would be really appreciated!

 

Thank you everyone!

[arcasey]

If you have play in one of your wheel bearings and it is noticeably louder than the other one, I think you have a good place to start. If they have never been changed it's probably time anyway.

[bisakm6]

It would be good to change those anyways. Is it suggested to do both at the same time? However, could something else be moving when shake the wheel? It seems hard for me to believe that it's a wheel bearing from 1 day of driving to get this loud.

[arcasey]

Yes it's always a good idea to change both at the same time. There shouldn't be anything causing the wheel to have play as long as everything else is in working order. If there is something in the front end that is bad you would have probably noticed a huge difference in the handling and ride of the truck. What could be happening is that it may have been slowly going bad and you just happened to notice the noise the other day and now because you have heard it it is more prevalent. I can tell you that I had a wheel bearing that was bad and I never heard any noise from it. I was rotating the tires one day and just happen to notice the abnormal amount of play in the hub assembly. Never heard any kind of roaring or grinding noise from it. You could be having some noise from the differential. You'd have to pull the CV axles out in order to isolate the differential noise. A lot of times when wheel bearings go bad you can get low speed ABS activation. Have you noticed anything like that?

 

My opinion is you know the wheel bearing is bad, so I'd go ahead and change those before they get really bad. Once those were fixed then I see if the issue still remains. If it's still there then I would probably start looking at the differential.

[bisakm6]

Wow I appreciate that. Being in 4x4, after putting it straight to 2wd it felt like it was still activated in 4x4 from the turning test. Is there an actuator motor or anything like that that can go bad?

[arcasey]

Do you have electronic push button 4x4 or manual shift on the floor? I would probably guess manual on the floor.

 

Your front drive shaft should free spin if the truck is not in 4WD. That's an easy test to see if things are still locked together.

[bisakm6]

Manual T-case shift, no push button. So I can activate the 4x4, then put it into 2wd and jack the front up and see if the tires spin.

[arcasey]

You don't even have to jack it up, in fact for what you are trying to figure out it may be better not to. Just shift your truck into 4WD and drive it around and then shift it back to 2WD. If everything is working properly you should be able to turn or rotate the front drive shaft without any of the wheels spinning. If the drive shaft is hard to rotate then either the actuator in the differential is faulty or the T-case is not completely shifting out of 4WD. You will be able to tell if something is still linked together.

[bisakm6]

Thank you!! I will try that

[bisakm6]

Ok I just tested it. Put it in 4x4 (made sure it was in), then put it in 2wd, put the E brake on and checked it - the front driveshaft did not rotate. Drove it, put the E brake on and checked again - front driveshaft rotated freely. Maybe you just need to at least move the wheels before 2wd can be engaged. Anyways, maybe I should drain the front diff fluid and check for any metal shavings.

[arcasey]

Yea that sound normal to me. I don't know that it necessarily makes a difference but I always drive forward a short distance, then shift to reverse and roll backwards about that same short distance before I take off after shifting into or out of 4WD just to make sure everything is engaged/disengaged. Draining some fluid off the differential is definitely not a bad idea. In fact, if your not sure of the last time it was changed completely I would probably just go ahead and change it if you don't see any bad metal shavings. If you see heavy metal shavings I would just top it back off until you have time to work on it. No point in wasting good fluid in a wore out differential that needs work. I would also check the fluid in your T-case also. I thought I was having a noise in the front end and it ended up being the T-case. Driveline noises can sound like they are coming from a totally different area than they are actually coming from.

[bisakm6]

Yeah that's a good idea. What issues were you having with your transfer case and how did you narrow it down to that? It ended up needing replacement?

[arcasey]

My issue wasn't just the transfer case. I was experiencing a grinding noise while the truck was moving in any direction along with what I would describe as "bucking". I drained some fluid from the T-case and saw metal shavings in the fluid so I first thought the T-case was the problem and replaced it. With the new T-case the bucking stopped (only thing I can figure is the chain might have been loose) but the grinding noise was still there. I had a couple transmission guys listen to it and they were stumped. About a week later I lost the transmission going down the highway at 60 MPH while accelerating. Made a horribly loud whining noise when it blew up. I had that transmission built about 30k miles ago and it was supposed to be strong enough to handle 500 HP (I intended to put a 383 stroker in that truck at one point in time so that's why I had it custom built when it went out the first time). When I carried it back to the guy that built it the first time he said he couldn't figure out what was causing the original noise because when it broke it shattered a few parts into about 5-6 pieces each. Only thing he could figure is one of the original parts had a weak spot and broke off and caused the damage.

 

The way I narrowed it down was by jacking up the truck and putting it in 4WD with all the wheels off the ground. I knew by the noise that I had been hearing that if either the front differential of the rear end was the culprit I would be able to hear it by just spinning both differentials by hand. I had to remove the driveshafts in order to isolate each end. I spun them and didn't feel or hear anything out of the ordinary so I knew it had to be either T-case or Transmission. At that point I swapped the T-case for a refurbished case (couldn't get a new one for my truck) and a week later the transmission blew up.