Hello Car Talk Community!
First time poster here. Used to listen to Click and Clack every weekend, miss those guys.
We have had an issue with our minivan. I’m worried about it and my husband keeps telling me that I’m making something out of nothing. He struts around like he’s got a V-8 when really he’s a 3-cylinder kind of guy, so I’m not taking his word for it here!!
Our van is a 2007 Hyundai Entourage. We bought it with 100,000 miles. It now has 130,000 miles. We put a U-Haul hitch on it and used the van to pull a small (1,500 pounds laden) pop-up camper. During our time with the van, we have had three incidents. They all happened when towing the PUP.
Episode 1
We were heading out of a hilly campground and descending a long, straight road with a moderate grade. When we got to the bottom of the hill and were back at slow speeds, there was a hollow, metallic, echoey sound. The van remained on, engine running, but there was no power to move forward. Husband coasted to a stop, killed the engine, and restarted it. Everything was fine.
Husband cannot remember if he was gear braking – see below.
Episode 2
We were driving on a freeway through a mountainous area. We’d put in about three hours of driving so far that day. We were descending a long, steep pass. As the grade leveled out and Husband tried to accelerate, he found that he could not. He said it was like having the car in neutral but without the revving noises. We pulled over, killed the engine, and restarted. Everything was fine.
Husband was definitely gear braking (engine braking) during the descent. The van has an automatic transmission, but when in D (drive) you can push the gear selector into a channel with a (+) and a (–) sign. Husband gear brakes on descents when we are towing because he says that he wants to “save our brakes” in case he needs them in an emergency.
Episode 3
We were driving on a highway through a mountainous area. We’d put in 3+ hours of driving and had gone up and down many passes. We were descending a long, steep grade. Same as Episode 2, although power was not restored immediately after turning off the engine. Husband turned off the engine a second time and let it sit for about 2 minutes, then turned it back on and drove on.
I told him that we were getting a new car and he said that he had the problem “handled.” 
Other Notes
[1] During Episodes 2 and 3, there would have been enough noise inside the car (radio, etc.) that we would not have heard an echoey noise if there had been one.
[2] When Husband gear brakes, he tends to tug constantly on the gear selector. When the selector is in that special channel, it defaults into a middle position between (+) and (–). Husband says that if he just pushes the selector toward the (–) and then releases, nothing happens. So he tugs the selector into the (–) slot repeatedly until the engine stops shifting down, and then he just holds it there.
[3] We recently learned that the person who sold us the van had disabled the Check Engine light. We fixed this and cleared the codes, and the Check Engine light generally stays off. On long drives, when we have done 3+ hours of driving over hills (with or without towing), the Check Engine light tends to come on. I think the OBD code is P0174 (system too lean), but I’m not certain. I have it written down somewhere. One time Husband sprayed the MAFS sensor with a cleaning spray and the Check Engine light went off. Now he just ignores it.
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Sooooo, does this seem like a problem? Is our transmission failing? Is Husband ruining our van with his gear braking? I would be grateful for any of your knowledge!!!