"Thug" sound from 2001 Toyota Sienna

When I put my van on reverse, it makes this one big “thug” sound. It happens when van is rolling. That’s the only time it makes this sound. Is this a serious car problem that needs immediate repair? Pls. help. It has 129K miles. By the way, I have run over squirrels, an emerald swift, an armadillo, and even my husband (I backed into him by accident 4th of July of 2003. He’s OK and is still alive and we’re still happily married).

I’d first make sure that your spare tire or jack isn’t loose. They can make a racket if they are not secured.

It could be a bunch of different things:
Years ago I had a Saab that would do make a metal to metal bump sound when you’d go from forward to reverse or vice versa and then hit the brake. It would only do it once, until you go in the opposite direction.
It took me a while to find but the brake caliper mount must not have been tightened correctly and it had worn its mounting hole to be elongated so the caliper was allowed to float back and forth.

Tell your husband to keep and eye on your reversing lights when he stands in the back of the van and run like heck when he sees them turn on.

There could be some play in the driveline somewhere. Probably a good idea to at least have a mechanic put it up on a lift and check it out. There may be something about to break, and you don’t want that to happen and strand you. I had a problem like this on a VW Rabbit years ago and ignored it, and the CV joint broke on a remote stretch of road up in northeast California. Definitely inconvenient. And expensive. Better to fix it in town on your own schedule if you can.

I’ll add that whenever I have an unknown noise in a car, I’ve learned the first thing to do is remove everything from the passenger compartment and trunk, including thespare tire and jack, and see if that makes the noise go away. Sometimes it is just something in the car banging around.

Doesn’t apply to you, but I had a noise problem one time when even removing all the junk didn’t work. I discovered the cause ;ater to be very simple: the rear window had been rolled down a tad, like 1/4 inch, instead of being fully up, and this was causing a weird thumping-like noise when going down the freeway.

Thanks a bunch, RemcoW. I always thought it was related to the brakes.

I actually blamed my husband for multi-tasking; on the phone while opening the gate for me, lol… I usually ask my kids to open gate for me except that day. I never had the problem of backing up on them because they always get out of the way. Oh well, tough way to learn to survive my crazy driving.

And yes, I gave him your advice. Thanks again.