Grinding Noise

GaryL · April 24, 2006

Hey all. Just found y'all today and have a question for you. My dad has a 94 K1500 Suburban and over the weekend it started making a grinding noise in the front end. It sounds like it is trying to engage the 4wd at random times while you are driving. It has the floor shifter. If you put it in 4wd everything works fine. Anyone run across this before?

Thanks

asilverblazer · April 24, 2006

Does it pull left or right? I wonder if the actuator could be getting lazy holding the differential open, allowing the differential to try engaging even though it isn't supposed to... I've heard the older thermal actuator are prone to failure not sure if your model applies. Also if that does turn out to be the issue I don't think they are hard to fix. I don't really know but maybe someone that does will comment.

GaryL · April 24, 2006

I haven't driven it yet, but he has not mentioned that it pulls one way or the other.

GaryL · April 25, 2006

OK, I just drove the truck. With the selector in 2H, when you start to accelerate from a stop, it grinds pretty bad, but does not pull to one side or the other. When in 4H, everything is as it should be. I disconnected the plug for the solenoid that engages the front differential and it still grinds in 2H and not in 4H, so that tells me it is something with the transfer case. Anyone know of any problems with leaving it in 4H with the differential solenoid disconnected for a few days while I work this out?

Thanks.

asilverblazer · April 25, 2006

I don't think running it in 4h is as bad as this mystery grinding. If you are driving and go from 4h to 2h will it be OK and then eventually go back to grinding or is it instant? It definately sounds like something isn't fully disengaging, from there I'm at a loss.

GaryL · April 25, 2006

I just talked to a local transmission shop and the owner told me that these things are prone to breaking a snap ring just in front of the drive shaft in the transfer case. He said I have to remove the drive shaft and then the housing and I should find the broken ring just inside. He gave me a new re-designed snap ring to replace the broken one with (GM part # 12470554). I am going to try to get to it tonight and let you know what I find.

GaryL · April 26, 2006

Worked like a champ. I pulled the rear driveshaft and output shaft housing and there was the broken snap ring. I installed the new one, reassembled and everything works perfect, no more grinding. In all, it took about 45 minutes.

gnuman · June 4, 2006

Worked like a champ. I pulled the rear driveshaft and output shaft housing and there was the broken snap ring. I installed the new one, reassembled and everything works perfect, no more grinding. In all, it took about 45 minutes.

<{POST_SNAPBACK}>

GaryL, thank you. I had the same problem come up this week and a search on many sites brought me to this thread. I pulled the shaft housing off and there was the snap ring broken into three pieces. 45 minutes and $8.00 later my 95 Tahoe was back to normal. I was ready to pay big bucks to a tranny shop to fix it for me. And thanks again for that part #.

happy camper,

gnuman

gnuman · June 4, 2006

....anyone know why this snap ring would break in the first place?

snoman · June 4, 2006

....anyone know why this snap ring would break in the first place?

<{POST_SNAPBACK}>

Generally abuse or too much driveshaft torque. When vehicle has tall gear and big tires it can really add a lot of driveline strain that some seem to ignore. A binding slip yoke can add to it too.

gnuman · June 6, 2006

Thanks snoman. No fancy lift kits or oversized tires. Strictly stock daily driver. The driver, however, is my wife and dispite some rigorous interrigation on my part, she denies any abusive driving...... She is notorious for cutting corners and driving over curbs. I wonder if that could do it....

thnx again,

gnuman

snoman · June 6, 2006

She is notorious for cutting corners and driving over curbs. I wonder if that could do it....

If she does that and the slip yoke is binding it could very well take out the snap ring. You might double check it because GM had some trouble with them binding on some models and that snap ring is not design to take a lot of for and aft thrust from a binding slip yoke.

gnuman · June 6, 2006

What's the slip yoke?

snoman · June 7, 2006

What's the slip yoke?

<{POST_SNAPBACK}>

The ujoint flange that slides in the back of the transfercase that attaches to drive shaft (it slides in and out for axle an flez for road travel and drive line torque and if it bind it places a load on load on the snap ring in question)