Truck is an 03 4x4 with 148k miles. Was out in the snow last night/this morning and using 4wd. First time I've used it, but I'm sure not first time the truck has used it. Couple times I lost traction in low speed maneuvers, rear end hopped a little. Stopped, put in 4wd, and slowly went on my way. It happened a couple times, mostly backing out of snow covered driveways from a dead stop. Now even in 2wd on smooth pavement I'm hearing a light "clunk clunk clunk" from the rear. It's barely audible when I'm slowing to a stop. No change in behavior of the truck, just the noise is new. What did I break? Or did I not break anything and just would benefit from a fluid change in the rear axle? Front axle doesn't make any noise, neither does T-case. Thanks for input.

-J

 

my first guess would be a driveshaft U-joint. Crawl under the truck and try to rotate your driveshaft my hand. (grab it and twist, see if there is any play in it and you hear the clunk)

If not, jack the rear end up and rotate your tires by hand, check for the sound. (when you rotate 1 tire, the opposite tire should rotate the other way) Then start the truck and put it in drive and check for sound.

if you dont know if the rear diff fluid has been changed, then now would be a good time to do it. When you have to cover off, check the magnant. There should be a metallic paste on it, no huge chunks. then rotate your ring and pinion and visually check that for cracks or chips. After draining it, give it a healthy spray with a degreaser, let that drain for a couple more hours then bolt it back up and fill it up.

Depends on what you find will be your next step.

 

I agree with Sevir. Do what he suggested, Then go from there...

 

You might want to have a look at the rear brakes. I have seen a few where water will seep in between the brake pad and its backing. Then it freezes and causes the brake pad lining to separate from its backing plate. Now the lining is loose in there and can move around a bit. It will rattle and click while you are using the brakes, but it can't fall out. It's also impossible to see it without actually removing the calipers.

 

Thanks all for the suggestions. Sevir, I am somewhat unable to get this done today as the truck is parked and in my apt parking lot there is minimal room (esp due to the large mounds of snow I had to park on due to snow removal...). Should I not drive until I can get the fluid changed? Latest would be this weekend. I appreciate the input.

Oh and I'm feeling a slight clunk at initial tip in of throttle and when I let off the throttle typically to just coast down the road. I thought I read somewhere that that also was a small sign of the u-joint going...

-J

 

Sounds like the u-joint would be my first look. My wife drove on one making noise for months before she asked me what the noise was, and I have had them go right away. I would change it ASAP

 

without pin-pointing what is making the sound, its hard to say if its safe to drive or not. it could be anything from a U-joint, to something in your pumpkin, to a bearing, to your brakes. Without knowing whats making the noise/clunk i cannot say its safe to drive or not. If you have a alternant means of transportation i would take it. If you must drive it, then do so and check what is causing the noise ASAP.

 

Thanks I figured I should do it ASAP, but until I at least check the driveshaft and change fluid I guess I'll park it. I searched rock auto and found a SLEW of u-joint possibilities for the rear driveshaft. Does this look ok?

PRECISION Part # 351A More Information About this Part U Joint - Premium
4WD; w/6 Spd. Man. Trans.; Position: V4- Rear Driveshaft at Transmission; V5- Rear Driveshaft at Center Bearing; V6- Rear Driveshaft at Rear Axle

Any feedback on Precisions? Assuming it's a u-joint........ this is all speculation until I get under there.

-J

 

I have never had good luck with Precision. I find their seals are sloppy and tend to let in a lot of moisture and gunk. Also, I can't prove it but I'd swear their dimensions are a bit inconsistent.

My choice has always been the Spicer Life non greasable joint that was used in the 2nd gen trucks. Just my opinion. Here's a link to the Spicer catalog, if you like: http://www2.dana.com/expertforms/dek350.aspx