PROBLEM!!!!!

[-[Rupes]-]

I was backing out of my parking spot this morning on my way to work when i noticed there was a fairly large knocking noise coming from the rear diff (or in that approx. area). I only heard it when i was in reverse.

 

Its on a 2002 Sierra 1500 2WD with a 4.3L. I think it might be the u joint, but im not 100%. Could anyone help me out???

 

thanks, brandon

[-[Rupes]-]

Noone knows what this might be???? I just dont want to pay for a diag if i dont need to. I can do the repair myself at my shop.

[67ChevyRedneck]

Does your truck have rear disk brakes? I can't remember what year they switched back

 

If it only does it in reverse I'd suspect that your e-brake has come loose on the disk. Mine is currently doing the same thing (00 silverado) and I haven't had time to pull the wheel and look at it, I'm not sure what the fix is, short of just tightening it, but I have read that it's a problem on these trucks.

 

Edit: It could be a u-joint too. For a u-joint check crawl under the truck (with the tires secure ) grab the driveshaft and try to rock it back and forth. If there is excessive play the u-joints are bad, (it will move a little bit).

[RyanZ71]

Do you have the G80 Locking rear diff?

[-[Rupes]-]

Does your truck have rear disk brakes?  I can't remember what year they switched back

 

If it only does it in reverse I'd suspect that your e-brake has come loose on the disk.  Mine is currently doing the same thing (00 silverado) and I haven't had time to pull the wheel and look at it, I'm not sure what the fix is, short of just tightening it, but I have read that it's a problem on these trucks.

 

Edit: It could be a u-joint too.  For a u-joint check crawl under the truck (with the tires secure ) grab the driveshaft and try to rock it back and forth. If there is excessive play the u-joints are bad, (it will move a little bit).

 

<{POST_SNAPBACK}>

 

 

I have heard of the e-brake thing but i never would have guess that was the problem. As for the U joint, i put it up on the hoist and checked for play, there was a little but not alot at all.

 

Do you have the G80 Locking rear diff?

 

<{POST_SNAPBACK}>

 

 

I am not entirely sure, i I got the base options on this truck. so i doubt that would be in there. Its a 2002 Sierra 4.3L Short box. if that helps

[GMCMan4.8]

Jack up the rear of the truck so both rear wheels are off the ground. Spin one of the wheels by hand (or drive shaft) turning drivetrain, then see if you can listen for a noise to find where it may be possibly coming from. That would be my 1st suggestion.

- Of course make sure to use all safety precautions if you're doing this and climbing under the truck.

[TonyMazz]

Well lets see...knocking noise....

 

It is real hard to say....I'd suggest first to have someone put your truck in reverse while you stand out side and listen.

 

Does it do it all time ? Every reverse ? or what ?

 

How many miles on the truck ? When is the last time you did a repair on it ? Did you change anything ? Have you done off roading, pulling, burning rubber...??

 

It's hard to diagnose a "hear a knocking noise"....could be when you back out and run over the kid next door his bike got caught under the wheels....we don't know...

 

 

Anyway....that was a joke

 

I would then bring the truck to your "shop" and through it up on jack stands go under and check the u-joints. Then'd in grab one wheel and move in clockwise-counter clock wise to listen / watch the u-joints.

 

Check suspension, bolts, shock connections, sway bar, frame, crossmembers too.

 

Then I'd consider pulling the back off the pumpkin and look in side. You can do a fluid change at this time anyway. But you'd be looking for a broken tooth on the spider gear.

 

If after all that you see nothing then it could be internal to the carrier assembly in the rear end, u-joints, or tranny binding....???

 

Tell us about your maintenance, acitivites....etc