Z71 Question: CV axles supposed to turn with wheels when 4WD is off?

**alwcurlz** · 09-14-2008, 08:18 PM

Z71 Question: CV axles supposed to turn with wheels when 4WD is off? I feel real dumb asking this question but, I never thought about all the times I've owned Z71s to check if those CV axles should turn with the wheels. The reason I'm asking this is because when I was trying to figure out what this growling sound coming from the front was, and spun the wheel, no sound was made. I looked inside and saw the CV axle turning when I turned the wheel. I thought, wait a minute...aren't these axles not supposed to turn unless some hub actuators are engaged? I put that side down and raised the other side. Same thing there as well. There has always been manually operated hubs and since what, about 87 Chevy has had automatic hubs? Both sides are turning the CV axles. Is this where that growling sound is coming from at lower speeds???

**CarpenterGuy** · 09-14-2008, 09:43 PM

My guess is it's the hub bearing. Mine do that too. I think the axle is connected to the wheel and the front differential. The front differential just isn't actuated. Correct me if i'm wrong. I"m not completley sure, thats just my take on it.

**MrShorty** · 09-14-2008, 10:55 PM

There is no disconnect at the wheels like in older 4w2d systems, so the axleshafts will turn with the wheel. The disconnect is in the differential and disconnects the axles from the front driveshaft

Wheel bearings sound like a definite possibility.

**alwcurlz** · 09-15-2008, 07:08 PM

Ok, thanks for the help/tips guys! I'll have to give those bearings a check this weekend and probably replace them.

**alwcurlz** · 10-04-2008, 04:05 PM

1999 Silverado 1500 Z71 with 133,000 miles on the driver side. I bought some bearing/hub sets and was going to put them in thinking the bearing was bad and was going to replace both left and right side. Well, when I had the wheel off, I spun the rotor and hear the growling noise but, not near the bearing hub. I put my ear near the differential and to my disappointment, the sound was coming from where the shaft goes into the case. The differential case is leaking. I checked the passenger side and it makes no noise. I wonder if I can continue to drive it like this and keep oil in it, will it be ok? A simple bearing replacement or total rebuild?
FixYa.com has a couple postings of the same thing.

**tbplus10** · 10-05-2008, 12:06 PM

If one side is growling its putting metal shavings in the lube system, which means sooner or later (probably sooner) the other side will start growling.
The whole unit has to be rebuilt, I dont know of many mechanics that would go in and replacebearings on just one side, and if they did I dont know if I'd really trust that mechanic.
You might look at finding a low mileage used front diff with the same gearing, then it'd be a simple r&r. The cost for a used diff would be close to the cost to rebuild your diff if it needs any extra parts.

**alwcurlz** · 10-05-2008, 10:56 PM

Originally Posted by tbplus10

If one side is growling its putting metal shavings in the lube system, which means sooner or later (probably sooner) the other side will start growling.
The whole unit has to be rebuilt, I dont know of many mechanics that would go in and replacebearings on just one side, and if they did I dont know if I'd really trust that mechanic.
You might look at finding a low mileage used front diff with the same gearing, then it'd be a simple r&r. The cost for a used diff would be close to the cost to rebuild your diff if it needs any extra parts.

Ok, thanks. I'll check into that. Could I drain the oil out, and put a magnet on the side to attract the shavings away that are left inside and refill?

**CarpenterGuy** · 10-05-2008, 11:05 PM

I'm sure you could. Tranny drain plugs are usually magnetic for that reason.

**tbplus10** · 10-06-2008, 07:34 PM

Yes, you could, but the damage has been done already. It's time to either have it replaced or overhauled. New oil probably wont take away the growling sound, and if it does it wont stay away for long.

**alwcurlz** · 10-08-2008, 12:22 AM

Originally Posted by tbplus10

Yes, you could, but the damage has been done already. It's time to either have it replaced or overhauled. New oil probably wont take away the growling sound, and if it does it wont stay away for long.

Yeah, the growling sound is there yet. I don't think it would cost that much to rebuild this front differential though. I saw a bearing/seal kit at AutoZone for about $150 I think.