4 wheel drive operation

[RamFP620]

I'm trying to figure out if something is up with 4-Lock. Back in the days when I had a Yukon and had it in 4-Hi all wheels would spin if I was on a slippery/loose dirt surface.
With the Ram, I need to it in 4-Lock to back the boat up the driveway/grass (slight up hill grade). If I stay in 2wd, the rear end will break loose on the grass. It is a limited slip diff so I have two dirt spots on the grass While in 4wd, the rear end will now sometimes break loose so I know the 4wd is engaged.

I'm now confused how the rear end will spin and not the front while in 4wd.

A side question, if I place the truck in 4-Auto what actually is happening? Is the truck like an AWD.

 

[NOV87]

To answer your last question: yes, 4auto will act like AWD. That means you have BW 44-44 transfer case.
The traditional part-time 4wd is BW 44-45 comes with basic trims (Express, Tradesman etc). Someone on this forum came up with a simple mod to make 44-44 act like regular old school 4WD. Search for it. There are also numerous threads about 4WD in RAMs here.

 

[Brandon-w]

I build a 44-44 lock switch that makes the transfercase lock Completely when switched on in any 4x4 setting. 4auto and 4lock are basically the same setting, it's a false sense of security per say. The rear wheels need to spin x amount of times before the t case sends power to the front axle. You basically have a 2wd till the wheels start spinning or until you activate my switch.

 

[tron67j]

I read this thread in the past, but it is an actual swap.

https://www.ramforum.com/threads/bw-44-44-to-bw-44-45-swap.132570/

 

[Brandon-w]

I read this thread in the past, but it is an actual swap.

https://www.ramforum.com/threads/bw-44-44-to-bw-44-45-swap.132570/

Yeah it's a good option too. With the 44-45 you lose the 4auto option though. And any warranty you might have left.

Other than that it's a direct bolt on, you'd need a new 4x4 switch and a reprogram with a dealer or alfaobd to change the t case type so it selects properly.

 

[RamFP620]

Wow...did some googling....not what I was expecting for a T-case.

If I understand it correctly, the 44-44 is a clutch based T-case...there is no chain?

Still a little confused on whether or not the front end is tied in to the drive train all the time. With what I've experienced backing the trailer up, putting it in to 4Lock does make a difference. Having said that, when the rear end begins to slip, is the T-case transferring power to the front at the same time and because of the clutches, the rear end can continue to slip even if the front is tied in to the drive train?

 

[Brandon-w]

The front diff is actuated in 4x4 and auto but the clutch is not. The t case is chain and clutch driven. Basically the drive gear on the t case is operated by a magnetic clutch. You can run the truck all day in 4x4 or 4 auto and your transfercase will never engage the front driveshaft unless there is some wheel spin. Some may engage faster than others depending on clutch pack tightness.

 

[Brandon-w]

Oh and like you said when reversing as an example the truck will only send power to the front wheels via the t case when the wheels are slipping. So when reversing the rear tires slip, the computer actuates the t case sending power to the front, the rear wheels stop spinning the truck cuts off the power to the front and the cycle happens over and over until you've got trenches, ripped up grass or a stuck truck with a t case overheat warning.

 

[kurek]

Still a little confused on whether or not the front end is tied in to the drive train all the time. With what I've experienced backing the trailer up, putting it in to 4Lock does make a difference. Having said that, when the rear end begins to slip, is the T-case transferring power to the front at the same time and because of the clutches, the rear end can continue to slip even if the front is tied in to the drive train?

There are two different points of disconnection.

The front axle has a disconnect which separates the passenger axle from the differential. This effectively disconnects the front driveshaft and the bottom half of the transfer case from the front wheels so when you're driving in 2wd you have minimum vibration and minimum fuel consumption from spinning those things all the time (remember the driveshaft spins at 3.21 or 3.92x the speed of your wheels.. )

In any of the 4wd modes (4Auto, 4H, 4L) the front axle disconnect engages both wheels to the differential and this means the driveshaft and the bottom half of the transfer case are moving any time your truck is moving even if the truck is not actually sending any power to the front wheels. This is a bit like on a very old (1980s or earlier) 4x4 where you'd lock the hubs so you could shift in and out of 4wd on the fly.

4Auto really is more like automatic 4wd than it is like AWD.. it's reactive. It requires wheelspin first before the computer will send a command to the clutches to lock them up.
If you look at a truly AWD vehicle like a Subaru, all four wheels are getting torque from the engine all the time proactively before any of them spin - if it takes 100 ft-lbs to start the vehicle moving on dry pavement than each of the 4 wheels will bear 25 ft-lbs. On a vehicle with automatic 4wd there is a primary drive axle that always works first until slip is detected and then power is sent to the other axle. If it takes 100 ft-lbs of torque to start your truck moving on dry pavement each of your rear wheels will see 50 ft-lbs and your front wheels won't see any of that in auto-4wd mode. It only begins engaging the front axle after slip has begun so that means you need to slip first or it won't even know to do its job.

I wish we could get a transfer case that was truly AWD when in automatic mode.. Mitsubishi does that on their overseas trucks. 2wd, true AWD plus 4H and 4L...

 

[RamFP620]

Thanks all for the info. When I first bought the truck I went on the fire roads to have some fun...came across a couple "puddles"...one being one that I could have gotten stuck in because of how this t-case operates, but I got lucky. Definitely had a false sense of security.