What to do when your rear end is gone

Dear Car Talk:

I have a 2006 Buick Rendezvous. My rear end is completely gone, so I've been told. I am a 65-year-old, single woman. I don't have a lot of money. What does that mean? – Ava

RAY: Not to worry, Ava. My wife tells me my rear end is completely gone, too. But she's still sticking with me.

The “rear end” is your mechanic’s shorthand for the differential. The differential is essentially a complex box of gears that allows the wheels to turn at different speeds when you take turns. Without it, you’d be dragging your outside wheel along the pavement whenever you turn.

Typically, when the gears wear out – or the bearings fail – the differential will start to howl. You’ll hear something that sounds like a deep whistling sound that goes up and down in pitch as you go faster and slower.

Sometimes it’ll go away when you step on the gas. Sometimes it’ll go away when you take your foot off the gas. The only symptom that’s absolutely consistent is that, over time, it’ll drive you cuckoo.

My late brother had a bad differential in his Chevy Suburban, and until he figured it out, he was convinced the cops were following him around everywhere. And that they knew about the plastic coffee urn he stole from his local International House of Pancakes in 1967.

If you’re short on funds and want to keep this car for a while, your best bet is a used differential. Differentials will often last the life of the car. If you found a Rendezvous in a junkyard, chances are its rear differential would be fine.

Now, we don’t want you climbing around piles of wrecked cars in a junkyard, Ava. Certainly not with your worn-out rear end. You need to find a mechanic who’s willing to work with you and help you out.

Your mechanic probably has a junkyard or two he works with. He can call them and track down the right part for you. Then he can install it.

It’s not cheap. It’ll probably cost you between $500-$1,000 including labor, depending on how much the part costs. But you can’t continue to drive with a bad differential forever. There’s a chance that it’ll seize up on you, and that can be dangerous, especially if it happens at higher speed.

So, if the alternative is to get rid of this car, spending 500 or 1,000 bucks probably makes sense, assuming the Rendezvous is otherwise in good shape. Get a mechanic to work with you, and good luck with your new rear end, Ava.

Trickle chargers from Toyota always stay connected

Dear Car Talk:

I went to Toyota to buy a trickle charger for my battery. They told me the charger they will install in my 2014 RAV4 will remain connected all the time – year-round. Does this sound right? – Elizabeth

RAY: It sounds great.

As you probably know, a trickle charger (sometimes called a battery tender) is a device that you plug into the wall and attach to your car’s battery. It keeps your battery topped up and ready to go.

You plug it in when the car is parked, and it provides a slow trickle of electricity to always keep your battery fully charged.

It’s particularly useful if you have a car that gets parked for long periods of time. So, while you’re at the International Slanket Convention for three weeks, the charger automatically senses a drop in the battery’s voltage and turns itself on and off as needed, keeping the battery ready to go when you get home.

Normally, when you buy a trickle charger at an auto parts store, you open the hood, you attach the clamps on one end of the charger to your battery terminals, and then you plug the other end into a wall socket. When you go to drive the car, you remove the clamps, close the hood and drive away.

Rinse, lather, repeat.

It sounds like Toyota has a trickle charger that gets installed under your hood and is permanently wired to your battery. There’s probably what we call a “pigtail,” which is like a short electrical cord that sticks out of the grill or under the front bumper.

So, when you’re heading off to the Association of Ginsu Knife Throwers meetings in Ketchikan, you just attach your household extension cord to that pigtail, and bingo, you’re all set. You never need to open the hood or fumble with any battery clamps.

It sounds very convenient to me, Elizabeth. I’d go for it.

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