Clunk when engaging 4H

[Goriders]

Pretty sure it’s 60 mph limit for engaging and disengaging. No limit on driving once engaged.

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[EastonTaco]

I had the same thing on my 2021 TRD Sport and now on my Gen 4 Sport. Seems to be less if I shift in and out while going straight and no stress on the drivetrain. One tip I learned from an old 4WD mechanic was to about once a month or so drop it in 4WD for a few seconds to move the lube around if 4WD has not been used for a while. And every so often get it in 4WD Lo for a few seconds. I try to do it on a rainy day where there is a little slip in the road.

 

[trailhunger]

...I mean...if you're in 4HI on highways, reduced speeds are a no brainer, liken it to 'safety nomenclature'.Assuming the engineering on these new trucks is good enough to run 4HI at whatever speed. It makes sense. I drove my TH 4HI across flat high alpine valley dry roads topping out at ~70mph for ~30ish mi, totally forgot about it until I pulled over to retrieve some food from the rear, drove out of this parking lot and could feel the 4WD grabbing, but couldn't detect it in the floor board or pedals on ultra straight highways where I was.

Switching in & out at 60 max more than plenty. My '01 Dodge has a 45mi limit for this.

 

[Nettle]

Does anybody else have this experience when engaging 4H there is loud clunk . It doesn’t happen every time . Most of the times it changes 4h very smooth . Just wanted to know if this is normal . Also some time’s after shifting to 4 h . Drive is very rough . Vibration feel in gas pedal . I did post about this earlier in summer . Most of the answers i got was bcz i was driving on pavement even though i drive straight . But now in winters on snow . Its same . Not sure why would it be rough . Dealership checked and said bcz there is less weight at back so it normal to have 4 wheel drive like this .

I've noticed a clunk as well, but only if the car is moving. I've resolved to only go in and out of 4H with the car stationary. I'm not surprised if there is a clunk since switching from 2H to 4H means changing the drive train configuration.

 

[GMak621]

So you can drive over 60mph in 4wd? I always get on the on ramp and turn it off when I get on the highway.... I always thought over 60mph would damage something? The highway where I live gets super icy sometimes but I always turn it off

Absolutely fine. I was in Lake Tahoe a few weeks ago during a crazy snow storm. Had it in 4hi through the mountains at speeds Well over 60mph. I wouldn’t even think twice about trying to do that in 2wd. This was what some of the roads looked like:

 

[Sagebrush]

60mph max for engaging is right. Is that what you meant Sage?

It's my understanding that you need to keep the speed below 60 when running in 4 HI??? Perhaps I' wrong?

 

[GMak621]

It's my understanding that you need to keep the speed below 60 when running in 4 HI??? Perhaps I' wrong?

There’s no limit on speed in 4hi. Send it

The 62mph 4H limit people love to quote is the speed limit on the shift from 2wd to 4wd High and back again. Once you're in 4H you can go at any speed the truck can.

You can almost reach 60mph in 4lo

 

[TacoFreak]

A really long time ago there was a top speed for 4Hi, and you had to stop to shift into 4wd. My brother in law had a truck like that, which I remember being a 1st gen Tundra.

Now you only shift into 4wd at speeds below 100 kph and there is no limit on speeds once in 4wd.

It's that simple, just as multiple people have already said.

 

[Sagebrush]

The 62mph 4H limit people love to quote is the speed limit on the shift from 2wd to 4wd

Thanks! I re-read it and I think you're right.

 

[MT-Taco]

A really long time ago there was a top speed for 4Hi, and you had to stop to shift into 4wd. My brother in law had a truck like that, which I remember being a 1st gen Tundra.

Now you only shift into 4wd at speeds below 100 kph and there is no limit on speeds once in 4wd.

It's that simple, just as multiple people have already said.

Pickup won’t let engage over 62mph. It also won’t let you go straight to 4LO. Basically do what it will let you and don’t worry about it. I’ve disengaged 4hi several times over 70 because I can.

Yeah sometimes It makes a little clunk but is totally normal.

 

[Brian2011]

Good to know! I recall reading that too..of all reminders on the dash, a 4 HI engaged for long periods would be helpful!

I am pretty sure 60mph is the max speed 4WHI will engage when activated not the max speed in the range.

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