I have a 2004 2500 4WD with the automatic tranny.

How fast can I be driving in 2WD and still be able to **** into 4WD high?

I heard it was 30MPH.

Is that true?

Thanks,

DT.

 

I was told any thing under 40 but I think I read some where that it was 55. I would not do it at 55 or 40. I try and put it in around 15 or slower. Check in your owner's manual.

 

I've done it at 50 or 55, no problem. As long as the wheels are not splipping and you are going in a relatively straight line (so front and rear wheels are spinning at the same speed) there should be nothing stopping you from moving the lever at 100.

I have the manual tcase, the electronic one could very well have a speed interlock on it.

 

According to page 229 of the owners manual you can shift the manual transfer case into 4Hi while moving at speeds up to 55 mph. It can also be shifted while you are stopped. "If moving it will engage faster if you momentarily release the accelerator pedal after completing the shift."

 

I have the 48RE with electronic shift transfer case. I went through the manual and as far as shifting from 2wd to 4 wdh, I could not find anything that related to speed. I guess you can do it just about any time as long as the wheel have traction and not spinning (lost of traction).

 

Yeah, I couldn't find anything in the pwners manual about the on-the-fly max speed limit for the 2wd to 4wd electornic shifting either.

That's why I posted the question.

Funny that's not in the manual.

Thanks...

DT.

 

I also remember the 50 mph number for shifting.
I think I read it on a tag that was hanging off the mirror when I picked up the truck.

 

My 97 had shift on the fly and I would shift it at interstate speeds
The trick was that you needed ot release the go pedel for a time ( what you had to do back then)

This new one seems to do it fine at same spees with no problem

 

According to the manual, you can engage it at up to 55mph. I've engaged it around 60-65mph with no nil effects. Like others said, just make sure the wheels aren't slipping/spinning when engaging.

 

I must be missing something here...........why would you want to engage 4WD at the 50+ MPH speeds mentiond above?

 

Please do so and report back with the results !

 

I have shifted at 80 mph many a times...no issues. Let off the go pedal and move that floor shifter. I will not vouch for the turn *** variety...never have trusted them.

 

" QUOTE "I must be missing something here...........why would you want to engage 4WD at the 50+ MPH speeds mentiond above?"

Snow, ice, rain, on the interstate, or any road. You should not drive in 4WD on dry pavement. I shift mine in and out at 65 mph no problems at all. Just let up on the peddle alittle to allow it to shift.

I am amazed by how little people use 4WD it in their trucks. If you got it use it!

Come to a complete stop and put in 4WD low once in a while also. It will keep the transfer case useable and working. Anytime I'm off road I use 4 WD high.

 

I haul a lot in 4 x 4 hi and low. In 4 x 4 hi, I normally shift while moving between 15-30 mph. No problems.

I have noticed when I leave the truck overnight (about 6-8 hours) shut down in 4 x 4 hi without moving back to 2 x 2 and re-start in the AM, I can hear a barely audible and brief grating noise from the transfer case.

So, I always shift back to 2 x 2 and drive a couple of hundred feet before shutting the truck down for an extended period. When I take this precaution the grating noise does not occur, so I assume it has something to do with the transfer case loading pressure when the drivetrain is resting overnight.

 

So let me throw my question in the mix. How are you guys shifting into 4LO. I do as the manual says, while going 2-3 miles per hour I shift into 4LO. However, that is the most violent shift I think I've ever had to make. When it gets to 4 LO, you can hear a loud CLUNK and the truck jumps and bucks for a second, and then you are in. Anybody elses do this?

My brother in law has a Ford F250 with **** used to shift into 4 lo, and it works fine (although he comes to a complete stop when he shifts into 4LO)