Engine/Transmission (1998.5 - 2002) Loud bang when hitting brakes in reverse

[Dave MacArthur]

I have a loud bang/crack when I hit the brakes hard in reverse (like when adjusting the brakes). As soon as I pull foreward and hit the brakes, I hear it again. Sounds like something shifting back into place. It takes a pretty hard stop when going in reverse to do it initially, but not nearly as much pressure when going foreward to "re-seat" whatever is moving/shifting. In other words, it doesn't happen when just normally backing up. What do you all think it is?



Thanks for your help,



Dave.

 

[jhurst]

This kinda sounds like the same problem I had on my '96 4x4. I believe the sound is coming from your upper or lower suspension arms. Try pulling on them by hand to see if there is any movement. Mine had a small amount of movement when I did that. If they move, the bushings either need to be replaced, or first, you can try just tightening up the bolts that hold them in place. Thats what I did and seemed to fix the problem. Maybe some others members will chime in with some other suggestions to try. Good luck!



Justin H.

 

[Dave MacArthur]

Thanks Justin. I'll try that first.



Dave.

 

[LSMITH]

It also could be the calipers moving forward or back in the knuckles. Mine does this too, sounds like a total POS. If it is the calipers there isn't a lot you can do. On mine I have to hit the brakes hard and fast to make it bang.

 

[jlccc]

Make sure your rear lug nuts are tight. If they are not tight enough then the drums can move a small amount relative to the wheel/rim and bang.

 

[Dave MacArthur]

O. K. I just came in from crawling around under the truck. The control arms seem tight. So do the bolts holding them. I didn't check with a torque wrench yet though. I may re-torque the control arm bolts. I checked a lot of other places and can't find anything loose. The calipers are tight also. I'll have to check the lug nuts.



Thanks for all the suggestions.



Dave.

 

[jhurst]

You might go ahead and tighten the bolts alittle bit. That should squeeze the rubber bushing making it tighter. Maybe get somebody to listen while you backup and stop to try and find exact location of the noise, front or back, drivers or passengers. The noise mine made came from the front drivers side suspension arms. Hope you get it figured out.



Justin H.

 

[Lsfarm]

Driveshaft spline

I would check to see if your driveshaft spline is lubricated and not sticking.



When you back the truck up, the rear diff is pulling the truck backwards, this rotates the diff to the rear, making the driveshaft lengthen [and the splines lengthen]. If the splines are sticky with rust or grime, they will stick in the extended position.



Then when you drive forward, the diff is pushing the truck, and trying to shorten the driveshaft as the diff rotates foreward. If the splines were stuck in the extended position, they may let loose abruptly and this makes the 'bang' you are hearing.



I've had several trucks of several makes make this noise. You may have to drop one end of the driveshaft to clean and lube the splines, or it may work to pump some gear lube through the splines instead of grease. The gear lube has worked for me on several driveshafts, some were badly rusted though, and had to be taken apart.



Hope this helps, Greg L [the noise nazi]