Hyundai Iload Gearbox & Transmission Problems

You took a share of the responsibility when you went to a clutch place and had a non-factory clutch and flywheel fitted. By doing that you opened the door for Hyundai to walk away from the problem. Had the dealer done the work they might well have found the gearbox problem and could possibly have fixed it under warranty. The only thing you can now do is to go to Hyundai and request goodwill assistance to fix the gearbox problem.

There doesn't seem to be a huge number of similar complaints to yours, Len, but that's pretty cold comfort. You could have a problem with the transmission itself or the electronics that control it. Either way, it could be that the transmission is stuck in high gear as a form of limp-home mode to avoid doing any further damage to itself.

The first step is to have the vehicle scanned for fault codes. Sometimes, a fault will be logged that seems to have nothing to do with the symptom, but can still cause the havoc you're experiencing. Try a transmission specialist first, as it's a fair bet they will have seen this exact problem once or twice before.

I've driven quite a few iLoads and none has exhibited the problem you talk about, and we've had no other reports of this issue from other owners, so it could well be something affecting your van alone. I would persist with the dealer and ask for a fix of some description, which could case of adjusting pinion preload, and if you aren't satisfied with your dealer's response take your complaint further up the chain by talking directly to Hyundai.

There’s every chance this is caused by a small amount of wear and slack in one of the joints in the driveline. If that’s the case, those joints and couplings need to be checked and the worn one(s) replaced, as continuing to drive as it is could see the driveline fail spectacularly at speed.

The reason you feel the jolt on the flat and not when you’re parked on a hill is that the driveline is relaxed on the flat, leaving a little slack for the thump to occur. When parked downhill, gravity has caused the driveline to take up that slack (plus your foot is probably on the brake, preventing the car rocking or moving at all) so the thump can’t occur and, therefore, isn’t felt.