Loud "bang" from the back?

[devilsfan]

I know this is a major long shot, but you never know. I had to make a fast U-turn off the side of the road yesterday after I missed my turn. There were about 5 big rigs speeding in my direction so I threw it into reverse and backed up fast. As I was doing so, I heard a huge BANG from the rear of the truck. I got out of there and it seemed to drive fine.

About an hour later, I had turned the steering wheel hard to parallel park and heard it again. Nothing seemed out of place, nothing dripping. The sound is as if I backed into concrete post at 40 mph. It's crazy loud.

Ran it a bunch today and nothing seems an issue - steering and suspension seem fine, no rougher ride than usual, no drifting.

I can't think of a reason to take it in to the shop if there's nothing wrong with it, but those noises are NOT normal and I'm worried I'll be on the freeway when whatever it is that possibly went bad decides to break for good.

Anyway, to get to the point - has anyone ever experienced this with their truck before, and if so, what did it turn out to be? Truck has a 12" suspension lift and aftermarket exhaust, if that helps any.

Stacy

[jsbihn]

does this happen only when you drive in reverse? or when you shift from drive to reverse or vice versa? have you checked all your connections and links for any look bolts or anything?

[HUMTECH]

If your hard on the brakes and then reverse direction it might be rear driveshaft slip yoke binding in transfer case output shaft. Braking hard will change driveline angles which could cause yoke to cock on output shaft. When it releases will be rather abrupt. Worn trailing arm bushings will make this condition even worse as they will allow diff to rotate out of position more.

[devilsfan]

HUMTECH - so, in laymans terms - is this something I need to take it into the shop for?

[guruerror]

Originally Posted by devilsfan

HUMTECH - so, in laymans terms - is this something I need to take it into the shop for?

If it was my rig...I'd say 'yes...definitely.' Having something like that snap on a trail would be a major PITA. Especially since most rural part stores near where we wheel are on bible-belt hours during the weekends.

If you're strictly a pavement pounder I'd say it can prolly wait a while since you typically wouldn't be stressing it the way you did with the hard brake and reverse, and if it does give you'll be easily accessible for a tow.

Originally Posted by HUMTECH

If your hard on the brakes and then reverse direction it might be rear driveshaft slip yoke binding in transfer case output shaft. Braking hard will change driveline angles which could cause yoke to cock on output shaft. When it releases will be rather abrupt. Worn trailing arm bushings will make this condition even worse as they will allow diff to rotate out of position more.

You, sir, are a wealth of knowledge. If you ever get bored here, feel free to check out clubhummeroffroad.com.

[jsbihn]

Originally Posted by guruerror

You, sir, are a wealth of knowledge. If you ever get bored here, feel free to check out clubhummeroffroad.com.

I completely agree.