4x4 Part Time Selectable Engagement vs Advanced On Demand Auto Engagement

[King Luis]

So what is the difference between the two 4x4 engagements? Does the part time selectable mean you have to move the dial from 2wd to 4wd yourself where the other has a automatic mode? the the advanced on demand is an option for the lower half trim levels. wonder what cost they would put on it and if there is anything mechanically different

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[jtzako]

I havent seen what the selector looks like but the "4A" would probably be in 2wd unless it detects slipping then it can engage the front diff and act like an AWD car. If you were off-roading you'd still want to select 4H or 4L. There would likely be some mechanical difference since the transfer case would need to have a way to allow 'slip' like AWD does.

 

[King Luis]

there are the selectors. so would the part time (standard on lower trim levels) not have the 4A?

 

[ZackDanger]

So what is the difference between the two 4x4 engagements? Does the part time selectable mean you have to move the dial from 2wd to 4wd yourself where the other has a automatic mode?

This is exactly correct.

 

[King Luis]

This is exactly correct.

thanks. so imo, not work the extra money unless part of a larger package.

 

[Tdifonzo]

I believe 4A will work like Audi Quattro in that you can just leave it in that mode and the car will switch back and forth based on the information it received from tire slippage. I actually prefer this mode (coming from an Audi) if it doesn't cost an arm and a leg (it will).

 

[Mopar2Bronco2021]

I havent seen what the selector looks like but the "4A" would probably be in 2wd unless it detects slipping then it can engage the front diff and act like an AWD car. If you were off-roading you'd still want to select 4H or 4L. There would likely be some mechanical difference since the transfer case would need to have a way to allow 'slip' like AWD does.

This feature would be nice for all the heavy rain in Houston, but it’ll probably be overpriced. If it’s less than $500 I’m all in. Other wise, I’ll just drive slow as hell in heavy rain which is the proper thing to do anyway haha.

 

[Mopar2Bronco2021]

I believe 4A will work like Audi Quattro in that you can just leave it in that mode and the car will switch back and forth based on the information it received from tire slippage. I actually prefer this mode (coming from an Audi) if it doesn't cost an arm and a leg (it will).

What Audi do you have because that would greatly vary what you’re expecting? For example a Q7 or S7 has has a Torsen based AWD from Quattro which is more like a true 4x4 in the sense that it’s normally split 50/50 between front and rear. Whereas the Haldex Quarttro is more like what others have described in that it will only engage AWD once slippage occurs. Haldex is in VWs and lower model Audi’s like the A4.

 

[rkj__]

This feature would be nice for all the heavy rain in Houston, but it’ll probably be overpriced. If it’s less than $500 I’m all in. Other wise, I’ll just drive slow as hell in heavy rain which is the proper thing to do anyway haha.

I drive a pickup, and even with a V8 up front, and an empty bed, I always keep it in 2H for rain. The only time I get significant slippage is accelerating briskly from a stop in wet, near freezing temperatures, when I have not yet switched to my winter tires. My driving style is typically pretty conservative, and I adjust to suit the conditions.

The only other note, is right now, I have newer tires on my truck, so things are pretty good. I was getting more slippage on my old truck with old (~8 years), worn tires. With a LSD in the rear, I actually had to be quite careful in that scenario. So, I suppose if you have poor / old / worn tires, I can see using 4A in the rain sometimes. FWIW, my old truck did not have 4A (new truck does).

 

[NCOBX]

It’s not worth it in my opinion, a lot of these newer auto 4wd systems are using clutches in the transfer case to control this activation. Accidentally Leaving it turned on off-road risks overheating the clutches and costing you a transfer case. On the street if it needs to activate due to rear wheel slippage at speed it’s already too late to help the situation.

It is a passive system, I have plenty of experience with it and don’t see the worth for an off-road vehicle. I will say if your running hard eco tires in the rain that love to spin every stop light it can come in handy, otherwise I prefer the more basic transfer case.

 

[Tdifonzo]

What Audi do you have because that would greatly vary what you’re expecting? For example a Q7 or S7 has has a Torsen based AWD from Quattro which is more like a true 4x4 in the sense that it’s normally split 50/50 between front and rear. Whereas the Haldex Quarttro is more like what others have described in that it will only engage AWD once slippage occurs. Haldex is in VWs and lower model Audi’s like the A4.

Absolutely. I have the Haldex in my S3 so the 4A would basically be the opposite of that where the rear wheels are the main driving wheels and front wheels will be driven only when needed Not true AWD but great for those pesky MPGs. I wonder if this will act differently depending on which GOAT mode you are in.

 

[Mopar2Bronco2021]

I drive a pickup, and even with a V8 up front, and an empty bed, I always keep it in 2H for rain. The only time I get significant slippage is accelerating briskly from a stop in wet, near freezing temperatures, when I have not yet switched to my winter tires. My driving style is typically pretty conservative, and I adjust to suit the conditions.

The only other note, is right now, I have newer tires on my truck, so things are pretty good. I was getting more slippage on my old truck with old (~8 years), worn tires. With a LSD in the rear, I actually had to be quite careful in that scenario. So, I suppose if you have poor / old / worn tires, I can see using 4A in the rain sometimes. FWIW, my old truck did not have 4A (new truck does).

I experienced the same in my old Ram truck. That thing would get LOOSE in the rain lol

Absolutely. I have the Haldex in my S3 so the 4A would basically be the opposite of that where the rear wheels are the main driving wheels and front wheels will be driven only when needed Not true AWD but great for those pesky MPGs. I wonder if this will act differently depending on which GOAT mode you are in.

That last part is a very interesting point...if the GOAT modes change up the resting torque split, then that would make the advanced 4x4 worth some extra money. If it does, I guess the “Slippery” GOAT mode would make the 4 Auto more like a true AWD.

 

[jtzako]

This feature would be nice for all the heavy rain in Houston, but it’ll probably be overpriced. If it’s less than $500 I’m all in. Other wise, I’ll just drive slow as hell in heavy rain which is the proper thing to do anyway haha.

It'd be useful here in CO too for winter driving. I love AWD cars here for that time of year. (there's not usually enough uniform coverage of snow/slush on the road to use proper 4wd)

 

[vrtical]

up to F150 XLT 4x4 packages you get standard 4H selection, higher trims you get the 4A. 4A is nicer since you dont have to mess with taking it out of 4H in conditions where the pavement your are on goes dry

 

[Mattwings]

I have had both systems and as long as the tranfer case can mechanically lock when actually off road, I think it makes sense, particulalry in those areas that get snow (here in MI for sure). My current 2018 Explorer has always on AWD and it is nice to not have to worry about changing conditions. It works pretty well in it's various off road modes as well. The limiting factor is ground clearance first and then probably tires. It is actaully a beast in anything that doesn't get it high centered.

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