4A or 2H? Which is the best?

[BigGreenPony]

I came across this issue by accident. I usually switch my truck to 4A for adverse conditions, such as rain, snow, or sleet. This morning I did not turn it off after a big rain and I noticed that the front end felt a lot tighter and the truck handled reasonable better (Not that the handling was terrible before). So, I now have the question, will running my truck permanently in 4A reduce my fuel economy due to all the extra drive train? Has anyone on this forum tested this?

I'm currently get 18-19 MPG combined on a 2.3 Badlands Sasquatch manual truck.

Sponsored

 

[Flying Skunks]

sure , it would take away some mpg , but i agree . I also put mine in Sport mode when the wx is bad , or the roads are crappy . Sport mode also puts it in 4A

 

[JBlanco]

I don't think I've notice a difference in the front end between 4A and 2H.
Are you sure you didn't switch to 4H instead of 4A?

 

[BigGreenPony]

sure , it would take away some mpg , but i agree . I also put mine in Sport mode when the wx is bad , or the roads are crappy . Sport mode also puts it in 4A

I still need to ForScan sport mode onto my truck. If it's only a nominal difference in MPG, it might be worth it.

 

[BigGreenPony]

I don't think I've notice a difference in the front end between 4A and 2H.
Are you sure you didn't switch to 4H instead of 4A?

I'm pretty sure it's in 4A, but I'll check. My understand of how it works based on what I have read is that 4A allows slip and 4H locks the transfer case. I certainly wouldn't want to use 4H on the road!

 

[Aonarch]

Yes you will lose MPG while it runs with the front diff engaged.

The driveline for the 4A models are designed to be driven in "4H" without binding, whereas the non-4A cannot.

You can just leave it in 4A. I know a ton of people here do.

Personally I prefer to be the one in control, so no 4A for me.

 

[Dreamer]

My badlands is not a Sasquatch and has an automatic. I agree about the front feeling a little heavier when in 4A mode. Found the gas mileage appears to be about 1 mile per gallon better in 4A versus 2H

 

[BigGreenPony]

Yes you will lose MPG while it runs with the front diff engaged.

The driveline for the 4A models are designed to be driven in "4H" without binding, whereas the non-4A cannot.

You can just leave it in 4A. I know a ton of people here do.

Personally I prefer to be the one in control, so no 4A for me.

I'm not locking the front diff, just the center diff/transfer case. I'm pretty sure that 4A is "unlocked" or slip for on road driving and 4H locks the transfer case so front and rear prop shafts can spin at the same speed. I wouldn't want to snap an axle with the front diff locked haha!

I'll try it for a while and see what happens. Thanks!

 

[BigGreenPony]

My badlands is not a Sasquatch and has an automatic. I agree about the front feeling a little heavier when in 4A mode. Found the gas mileage appears to be about 1 mile per gallon better in 4A versus 2H

I think I'll try this then. I image that the non sas badlands has much less drive line resistance due to 33 tires and not 35s. Maybe this is partially due to the front axle not being dead weight? Maybe @Ford can confirm?

 

[userdude]

My badlands is not a Sasquatch and has an automatic. I agree about the front feeling a little heavier when in 4A mode. Found the gas mileage appears to be about 1 mile per gallon better in 4A versus 2H

2dr Badlands Sas w/high, I ran in 4a for most of a year and got very similar gas mileage. Recently switched back to 2h before getting the front pinion fixed and been running that last month, it does feel different but I also don't have skid plates on.

 

[604Bronco]

I just leave my Bronco in 2H for 99% of the time. I've even started hitting some trails just in 2H, until I am forced to switch into something else. In extremely torrential rain, I'll sometime switch to 4A for peace of mind.

Shouldn't be anything wrong with driving in 4A - It's meant to do the thinking for you and switch when required. I used to leave my Silverado in 4A all the time with no issue.

 

[userdude]

I'm not locking the front diff, just the center diff/transfer case. I'm pretty sure that 4A is "unlocked" or slip for on road driving and 4H locks the transfer case so front and rear prop shafts can spin at the same speed. I wouldn't want to snap an axle with the front diff locked haha!

I'll try it for a while and see what happens. Thanks!

I also drove 2.5 hours with 4h engaged (Baja mode) on the highway and didn't notice until I went to turn into my driveway. Someone said 4a allows 4h at higher speeds, which I guess explains that.

 

[brkdncr]

Unless 2h somehow disengages the rotating assembly at the front wheels and also at the transfer case then there is marginal mpg gains. The engine is still rotating all that mass with the exception of the friction between the gears that were disconnected.

 

[BadmansSAS]

I put mine in sport, then immediately put it back in 2h. I would only put it in 4A if the weather is bad. Otherwise no need for 4x unless going offroad. If I were to hit trails that were just off camber without any technical sections, I would just put it in 4A and let it eat until it needs help.

 

[BigGreenPony]

Unless 2h somehow disengages the rotating assembly at the front wheels and also at the transfer case then there is marginal mpg gains. The engine is still rotating all that mass with the exception of the friction between the gears that were disconnected.

I'm an automotive engineer (I never designed any drive train), but my understanding is that 2H the engine only turns the back axle.

Sponsored