Slow To Engage 4WD

graycenphil · **Posted:** Sun Dec 10, 2017 2:49 pm

First snow here. I usually stay in 2 WD until I need to. I like to know how slippery the road is, and it’s kind of fun to start slipping, switch to 4WD and go.

It has always engaged very smoothly and quickly. But yesterday, twice, when I put it in 4WD it didn’t engage. I drove a bit further, started really slipping and stoppped. Backed up about 50 feet, put it back in drive, and then it was in 4WD. Worked both times.

Is this an indication of anything? Problem, or adjustment? Anyting I should do?

Thanks.

geordi · **Posted:** Sun Dec 10, 2017 3:41 pm

Check your tires - they have to all be the same size and pressure, you might have a nail in one and have a decent pressure difference that you can't quite see visually. That can change the rotation speed enough to prevent the 4WD part time from engaging.

You also shouldn't be using part time on pavement, use full-time. That has a differential to prevent binding.

graycenphil · **Posted:** Sun Dec 10, 2017 4:21 pm

Thanks Geordi. The tires are fairly new, but I will check them carefully. No dry pavement here - the roads were totally snow covered.

mass-hole · **Posted:** Sun Dec 10, 2017 5:14 pm

Why not run it in Full time 4wd all the time. Then this won’t be an issue.

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graycenphil · **Posted:** Sun Dec 10, 2017 5:32 pm

Interesting idea, but I need the 4WD so rarely. I assume I’m getting worse mileage, plus more wear and tear while engaged. Plus, it’s so much fun to feel the difference...

mass-hole · **Posted:** Sun Dec 10, 2017 5:36 pm

graycenphil wrote:

Interesting idea, but I need the 4WD so rarely. I assume I’m getting worse mileage, plus more wear and tear while engaged. Plus, it’s so much fun to feel the difference...

Mileage shouldn’t change. The hubs on these jeeps don’t disconnect so everything between the transfer case and wheel is spinning whether you are in 4wd or not. Full time 4wd simply engages an open center differential to give power to both axles without binding.

I pretty much run it in full time all winter, even if no snow is on the ground.

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geordi · **Posted:** Sun Dec 10, 2017 5:40 pm

Yes, 4WD full time does reduce economy by about 2mpg. I don't know about any "more" wear and tear however, as the components are always rotating anyway.

The front propshaft is always spinning because the front diff is also always spinning. If you remove the CVs or if this vehicle had locking hubs, then you could say that the front mechanics weren't engaged at all while in 2WD and that would definitely make a big difference. But pretty much the only thing that isn't connected is the interlock between the front and rear. The transfer case is just in a front-disconnected mode, the internals are still spinning just as much (1:1) b/c it is a common connection.

In thinking about it, I'm not sure why it would actually make any difference, but I know having it connected does make a difference of about 2mpg. But the part-time mode just makes things bind on pavement when you turn.

Sergio del Castillo · **Posted:** Sun Dec 10, 2017 6:08 pm

I got the same snow storm yesterday here. I connect the 4WD FT when I get to go. Get the Jeep moving forward at about 3 or 4 mph, then stop and reverse 4 to 5 feet, enough to have at least one full tire rotation. That sets the transfer case fully engaged. Some times I have some delay in disconnecting, but i reverse the same procedure. Works every time. I use the 4WDFT not only with snow, but also with rain, mainly when it has not rained is a while. It drives more sure footed and give me peace of mind. Plus I paid for all that gears, why not to use it. Only drawback, reduces the turning radius some, but only bothers when parking in a tight space..

Slow To Engage 4WD

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