4wd Auto feels like 4wd High

[Pyleketerson]

I’m on my third winter in my 2020 Ram BTS (Bighorn). I don’t remember this happening before, but lately when I engage 4wd Auto the truck lurches and jumps around turns like it’s in 4wd High. Hopefully my memory isn’t fading at age 41, but I don’t recall the truck acting this way in the past. I wish there was a standard display on the cluster to provide real-time wheel power. Any thoughts?

 

[vincentw56]

Is this on slippery roads or dry? When 4WD engages in Auto mode, it will feel like 4WD Hi.

 

[crusher]

whats your diffenrential? is it the electronic lock or auto lsd ? any chance you left it lock?

 

[Richard320]

Thoughts, you say?

New tires this year that are a different diameter? Old bald tires slipping more than they used to?

 

[Pyleketerson]

I will only engage on variable surfaces ie. snow and ice. However, I’ll stop at a stop sign or light, and the intersection is dry, and I turn left or right and it still feels like I’m in 4wd High. Unfortunately I don’t know anything about differentials. I don’t see anything locked. My Falken Wildpeak AT3Ws (thumbs up on those) are still in great shape and provide amazing traction. 35,000 miles on them…plan to replace before next winter at approx. 50,000 miles. They still have plenty of tread life. Appreciate your feedback!

 

[Pyleketerson]

My front right CV axle was replaced last summer…

 

[crusher]

I will only engage on variable surfaces ie. snow and ice. However, I’ll stop at a stop sign or light, and the intersection is dry, and I turn left or right and it still feels like I’m in 4wd High. Unfortunately I don’t know anything about differentials. I don’t see anything locked. My Falken Wildpeak AT3Ws (thumbs up on those) are still in great shape and provide amazing traction. 35,000 miles on them…plan to replace before next winter at approx. 50,000 miles. They still have plenty of tread life. Appreciate your feedback!

do you have the axle lock button like in this.picture? if you do and its on, that could be why you feel it that way

 

[Pyleketerson]

do you have the axle lock button like in this.picture? if you do and its on, that could be why you feel it that wayView attachment 147111

Thank you. I do have the axle lock but it’s not engaged. I’ve been off road plenty but never pushed the button! I just checked to make sure.

 

[2021EcoDiesel]

Sweet rig man. I love my ram BTS, and I feel a similar way when taking slow turns on dry pavement. However my truck doesn't buck or jump/chirp the wheels in these turns, I just feel the front tires pulling me along and maybe some very slight binding. Not to blindly trust the computers in my 4wd system, but I believe the wet clutch in our transfer cases allows for some slip in situations like that. Unsure as to whether or not there may be long term effects from this little bit of binding, but I tend to really only use 4WD Auto when the roads are very wet or gravel/snow covered. I'm also running over sized tires and the computers have all been reflashed to accommodate a 35" tires over the factory 32.5's it came with.

 

[Scram1500]

I’m on my third winter in my 2020 Ram BTS (Bighorn). I don’t remember this happening before, but lately when I engage 4wd Auto the truck lurches and jumps around turns like it’s in 4wd High. Hopefully my memory isn’t fading at age 41, but I don’t recall the truck acting this way in the past. I wish there was a standard display on the cluster to provide real-time wheel power. Any thoughts?

Have you checked the tire pressure? A couple years ago I had the fronts over inflated and the rears under inflated, there was biding just going in a straight line as the rolling diameters were different front to rear

 

[LouNY]

When you are in auto 4wd the front axle connector is engaged so both of your front axle shafts are turning from the tires rolling,
the transfer case will not apply the wet clutch pack until the computer decides you have rear wheel slippage.
When it detects slippage it will send a variable voltage signal to the electronic clutch in the t case, it will also monitor steering angle
and use that value in deciding how much input to send to the clutch pak.
In auto 4wd under normal circumstances you may be able to feel the axle ujoints working while turning.

 

[Pyleketerson]

When you are in auto 4wd the front axle connector is engaged so both of your front axle shafts are turning from the tires rolling,
the transfer case will not apply the wet clutch pack until the computer decides you have rear wheel slippage.
When it detects slippage it will send a variable voltage signal to the electronic clutch in the t case, it will also monitor steering angle
and use that value in deciding how much input to send to the clutch pak.
In auto 4wd under normal circumstances you may be able to feel the axle ujoints working while turning.

Well there it is, I’m going with this one. Thanks, LouNY. Today was a bit warmer and snow turned to slush and some melted altogether on the streets. In 4wd Auto I could definitely feel the front axle shafts working but did not get the lurching while turning like you do in 4wd High.

Side note, I did engage 4wd LOW to pull a car out of an embankment today. Truck worked like a charm. This is a great rig. This is also a great forum to discuss these things. Thanks everyone!

 

[theblet]

When you are in auto 4wd the front axle connector is engaged so both of your front axle shafts are turning from the tires rolling,
the transfer case will not apply the wet clutch pack until the computer decides you have rear wheel slippage.
When it detects slippage it will send a variable voltage signal to the electronic clutch in the t case, it will also monitor steering angle
and use that value in deciding how much input to send to the clutch pak.
In auto 4wd under normal circumstances you may be able to feel the axle ujoints working while turning.

Don’t the CV shafts spin with the wheels at all times, even in 2wd? There’s no hub locks so I thought they did.

 

[ramhouston]

Don’t the CV shafts spin with the wheels at all times, even in 2wd? There’s no hub locks so I thought they did.

naturally they do.

 

[ramhouston]

4WD auto is 4WD auto but i never run that sucker unless the road surfaces are slippery. can’t afford to let that system take out my CV axles and etc..

 

[LouNY]

naturally they do.

Yes the shafts turn, but the axle disconnect allows the ring and pinion to not be spun, the spider gears in the differential do most of the running,
when the axle disconnect is engaged the ring and pinion are spinning and the front driveshaft is turning in sync with the rest of the drivetrain.