Going in 4WD over 45 mph

[Mabar]

I should add this is a 2021 JLU Rubicon to differentiate between different AWD/4WD systems.

The 2021 Rubicon JLU is available with standard 4WD (part-time 4-wheel drive), and optional Selectrac AWD (full time all wheel drive). There is a HUGE difference between the two. Which do you have?

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[neil]

Pretty sure ive driven over 45mph in 4wd in every 4wd vehicle i've owned in 40 years.

 

[Hound Dog]

Just yank that lever and find out.

If you hear loud grinding, a pop and then have no power to the wheels you will know the answer is no.

If you hear a click, the light on the dash pops on and you keep going then the answer is yes, no problem.

Not hard to figure out.

 

[BRuby]

Just yank that lever and find out.

If you hear loud grinding, a pop and then have no power to the wheels you will know the answer is no.

If you hear a click, the light on the dash pops on and you keep going then the answer is yes, no problem.

Not hard to figure out.

Haha!

What is more concerning is asking whether going 70 on the interstate in a snowstorm is ok in 4Hi? Use your judgement man. For this hypothetical - No one knows the true road conditions or if iced up bends are present or if the amount of traffic is a risk or whether there is any visibility in the blinding snow etc. Tons of variables.

But generally no this is not advisable. Drive at a speed that you can retain good grip with your tires yet maintain vehicle stability if you had to do an emergency stop. Otherwise you are probs driving over what you should and what conditions permit. 4Hi does squat when trying to stop on an iced up roadway.

 

[Hound Dog]

You know what Wyatt would say.....

 

[GtX]

Not true, it is there to enhance the vehicles performance in poor traction situation. It makes poor drivers drive better and better drivers better also. It does not say hey, this idiot doesn't know how to drive, lets help them out, it just does what it does.

Huh? I said traction control compensates for poor driver skill. Then you say "not true" but in the same post say "It makes poor drivers drive better".

Seems like we agree.

 

[wibornz]

Huh? I said traction control compensates for poor driver skill. Then you say "not true" but in the same post say "It makes poor drivers drive better".

Seems like we agree.

I am kind of slow, and not always of sound mind. So yeah, we agree.

 

[txj2go]

are you folks suggesting that the Jeep cannot be put into 4H and then driven around that parking lot at 65mph without doing damage to the jeep?

Operating the machinery at that speed will not harm it, as long as you don't run into anything. Operating 4H on surfaces with a lot of traction is the problem because of the locking center differential.

 

[Craigzjeep]

Newbie question. It's recommended to go into 4WD less than 45mph. What if I'm going 70 and hit a snow storm? Must I slow down on the interstate?

Did your parents have any children that survived?

 

[SecondTJ]

If you are using Selec-Trac then you are not technically in 4WD at 70mph. Selec-Trac will only engage the front axle when there is sufficient rear wheel slippage, and good luck getting sufficient rear wheel slippage at 70mph and living to tell us about it.

4Auto in Selec-Trac is 4WD, as the front axle is engaged and getting constant power.

The difference is the front & rear axles are not locked together like 4HI

 

[Ahre]

BTW - it was answered on page 1.

Thank you Raven,
The only 'answer' I could find was your response of 'Should Not be doing more than 45 mph'. Your statement of should not is also a recommendation and still leaves the question unanswered. It does not categorically state No you can not shift into 4H above 45 without incurring catastrophic mechanical failure or Yes you can shift in 4H above 45 though as stated in the owner's manual, it is not recommended (for an unstated reason).
Honestly I have a 2020 Manual JLUR and encountered a condition where I needed to shift into 4H above 45 mph. Granted I was not doing 70 mph. My dilemma was I had no clue what may happen to the manual transmission if I exceed the manufacturer's recommendation or whether-or-not the transmission would even go into gear.
I am still unaware of the potential mechanical consequences of exceeding the factory recommended limit of 45 mph or even if the factory recommendation is strictly for safety reasons.
With highest regard,
Paul

 

[wibornz]

I have shifted into and out of 4H well above 45 mph with no problems. You will run into a problem more likely if you try and shift into 4h when you are spinning tires in a loss of traction scenario and all the wheels are not spinning at the same speed.

 

[mtu1293]

Newbie question. It's recommended to go into 4WD less than 45mph. What if I'm going 70 and hit a snow storm? Must I slow down on the interstate?

Yes you can - the biggest issues comes into play, is to make sure you don't have a load on the tcase when you shift into 4hi (meaning don't be on the throttle when you shift in). You don't want to by using 4x4 when the roads are getting dry, but really on straightaways you wouldn't even notice. I use 4hi a lot in the winter, mainly due to slush conditions (they love to use salt in this area) or snow drifts on our highways. Typically my work hours start before most of the roads are plowed.

 

[TheRaven]

Thank you Raven,
The only 'answer' I could find was your response of 'Should Not be doing more than 45 mph'. Your statement of should not is also a recommendation and still leaves the question unanswered. It does not categorically state No you can not shift into 4H above 45 without incurring catastrophic mechanical failure or Yes you can shift in 4H above 45 though as stated in the owner's manual, it is
not recommended (for an unstated reason).

Theoretically no, there should be no problem mechanically...you will annihilate fuel mileage though.

The speed limit exists for safety...there is no situation where it is both possible and safe to surpass 45mph and you NEED 4WD.

You can click on the up arrow in the quote to see that it was posted on page one. Along with many other answers from other users.

 

[Hayseed_JLUR]

2 Doctors and a Physical Therapist. How's your parents do?

Your parents were 2 doctors and 1 therapist?

To answer your question and not pontificate on the merits of driving 70mph in a snowstorm. Under any road condition, it is not recommended to shift into 4H above 45mph. Like it has been said above (maybe once), it can be done higher but not the best for stability and mechanicalness of the vehicle.

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