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I have a Jeep Patriot 2.0 crd 2007 with 4wd. I went fishing and used the 4wd when leaving. Once i hit the tarmac i forgot to switch it off and drive 10 miles to home doing a speed of 50MPH. Is this dangerous for the transmission in any way? Thank you!

No unusual sounds. Thank you for your reply. I only pushed the 4wd button and did not deactivate the ESP.

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  • Were any of the differentials locked? – Caius Jard Nov 21 '19 at 15:37
  • What does the owners manual say? They are usually very specific on topics like this. – Tim Nevins Nov 21 '19 at 15:53
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I'm assuming that model has a simple 4WD transfer case and not one with a front-to-rear differential. That means that there is no "slip" in the driveline. Generally you feel this when you try to turn at low speeds as a "binding" often accompanied by creaking or popping.

For a vehicle in normal condition, this causes no damage other than slipping the tires.

If the vehicle is damaged, however, the added stress of this may cause something to break but that's unusual in my experience. 4WD vehicles are designed to handle this, it's not a good practice because it causes difficulty in steering under some circumstances and hurts fuel-economy but should not cause any long-term damage to your driveline.

If the vehicle has a fancier transfer case, then there is slip allowed there and there is no issue at all. Often these vehicles say "Full Time 4WD" or similar.

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  • +1; I agree that there's no reason to worry. It's also worth noting that it's not the transmission that would be subject to any sort of significantly increased stress from this (as mentioned in the question), but rather everything "downstream" of the transfer case, from the transfer case itself to the tires. – Josh Nov 21 '19 at 22:24
  • Not a Jeep, but my 4WD Tacoma's owners manual says I can be in 4WD up to 65mph. And I've done it while on interstates that had occasional wind-blown snow drifts to deal with. – Jon Custer Nov 21 '19 at 22:46
  • @josh You do need to be careful when using the word transmission, since it can mean different things in different locations - en.wikipedia.org/wiki/Transmission_(mechanics) – HandyHowie Nov 22 '19 at 8:09
  • @HandyHowie Thanks, didn't know that. – Josh Nov 22 '19 at 11:30
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No problems with that - the "4WD" button on the Patriot just locks the torque split at 50/50 between front and rear, normally the AWD system distributes power as slip is detected.

Driving on a dry highway at 50 you'll have used (slightly) more fuel with it engaged than not but that's about it.

To quote the operators manual:

This can be done on the fly, at any vehicle speed.

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  • Are you sure about the 50/50 torque split? That is exactly the action of an open differential, and is very likely to cause the vehicle to get stuck because as soon as you lose traction with either both front or both rear tires, the tires without traction will simply spin while those with traction will not turn at all. This is because with equal torque, the lack of any reaction force on the wheels without traction means that torque is nominally zero in that half of the driveline, which means it will also be zero on the other half as well. This is why diff locks and traction control exist. – Josh Nov 22 '19 at 20:52
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Thank you for all your answers. Called a Jeep dealer in my country and they said that above 35MPH the 4wd deactivates automatically and reactivates at lower speed. It continues to do so untill i pull the 4wd lock lever.

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