Shifting on the fly from 2WD to 4WD?

Haha Im a Tacoma and a Dodge owner!

My Cummins has the OG floor-shift transfer case, which is MILES better than the Ram electronic switch, but neither Dodge case is going into 4wd at 60mph like the Tacoma.

 

I’m partial to 19th at .05 RPM’s and that chugging right before stalling

 

Sorry for resurrecting an older thread but I'm a new owner 2023 Double Cab TRD Off Road.

This is my first 4x4 vehicle ever.

I have 1100 miles on it now and yesterday was the first time I engaged 4H while driving at about 52-55 mph.

Dry pavement but only in straight lines. To follow the manuals advice to exercise the components.

My question is out of curiosity. What happens if you engage 4H while going over 62 mph?

Will the computer protect the truck and not allow it until you are under 62 mph?

Or will it shift into 4H while beeping and flashing but risk damage?

Thanks for your time.

 

It will beep at you and not shift into gear...at least, that's what I've experienced.

Mind you, I only did it once. The manual tells you within a certain mph...take heed to that.

 

The 4wd ECU will reject the request and not shift. Technically, there's nothing magical about the 62 mph, it's just locked out by software. If it wasn't for the software it would still shift just fine above that speed, but it is a large ask of the synchro in the transfer case.

 

they say you can shift in 4hi under 60 but i've tried at 45 mph multiple times and it never works. just keeps flashing and makes a terrible clunk when shifting back to 2wd. works fine at low speeds though under 10 mph.

 

Thanks for your replies. Good to know there is protection in case you accidentally try to engage above 62.

 

So my experience in the frozen tundra of North Dakota, and owners manual my '04 was up to 69 mph preferably below 60 and not over 70mph . My '16 was <75mph or you got a series of beeps, on the shift into 4H. How ever it indicated in the '16 owners manual the automatic could be driven at a higher rate of speed I believe to have been 80. I was surprised. However at that speed, conditions to go that fast probably not there in 4 Hi.

 

If you really need 4x hi, you should not be above 60mph, most likely...

I've been on the edge, but when powering down in advance of the condition causing the need for 4hi, I am usually well below 60mph.

I find that taking the load off works great - and surely reducing stress in the system during shifting is better than the alternative...

Now at 15k miles, my 4x system shifting is FAST and buttery-smooth... barely audible and no flashing lights...

 

Not mine...while I've never tried it at 60 mph plus highway speeds, I've been able to shift in, and out of 4wd up to 50 mph flawlessly.

 

I shift between 2hi and 4hi at hiway speeds all the time during winter and I’m sure I’m not the only one. There are days where the road will alternate between dry pavement and ice. I tend to leave it in 2wd and only use 4wd when it gets dicey.

I’ve never had it refuse to shift or misbehave in any way. I haven’t paid attention or worried about how fast I am going when shifting, so I don’t know if ever gotten over the magical 62 mph.

 

Come on man nobody reads that shit

 

I've engaged/disengaged around 55 before. Was always leary because keeping it under 45mph was always my understanding.
(Not that it won't let you at higher speeds but under 45 was considered 'safe').
note: I back off on accelerator until it engages/disengages.

 

Same here, never had an issue of engaging at any speed and in the winter if the road looks a bit slick I’m usually doing 50 or less, take my foot off of the throttle and it slides right in and the same when I disengage it. I was impressed with the system my first winter owning a Tacoma, compared to other vehicles that had push button or dial.