Single speed transfer case

oldmann · September 7, 2018

So I guess some of the 4x4 truck do not offer 4low. I know many people don't use it ever or use it incorrectly, but wow! Anyone have details?

All Z71 have 4-low

RST doesn't offer 4-low.

GMC-AT · September 7, 2018

RST.. and any configuration for that matter that has Z71 will have duel speed transfer case with 4L. I have one on order now.

80% of the people that have 4x4 will never use. And when they do.. they will use 4H ..or "auto" most of the time.

I have a Sierra 4x4 and Silverado 4x4 and I'm in the woods every single week... and even I rarely ever need or choose 4L

rkj__ · September 7, 2018

This has been discussed a fair bit in other threads, but I'll briefly summarize my thoughts here.

In snowy areas of the world, almost everyone uses 4x4 once in a while. 4h serves fine for this.

The reasons I see for a two speed transfer case are:

1. Off road. Mostly for the type of rough trails that a stock truck would struggle on anyway. Most drivers don't do any tough trails.
2. Backing up or parking a trailer. The extra torque is very handy if the transmission has a taller-than-first-gear reverse gear. Slopes or bumps can require a fair bit of torque to creep a heavy trailer over. The added control of 4L is great.

3. Pulling a boat out of the water. Some ramps are steep and slippery. The extra torque and control is great.

I could be wrong, but it almost seems to me like the 2-speed should be tied to max tow packages, in addition to the off road packages.

oldmann · September 7, 2018

I appreciate the extra torque when going off road in the winter to our camp. Sometimes 4H doesn't allow enough wheel spin in snow and slush and 4L shuts off all of the nanny controls.

Logan Lanfear · September 7, 2018

4L is definitely pretty handy when you have it. I wouldn't want to get a 4x4 truck without it. I wouldn't say I use it as much for traction purposes but more for getting a better gear when moving something.

mookdoc6 · September 7, 2018

51 minutes ago, GMC-AT said:

RST.. and any configuration for that matter that has Z71 will have duel speed transfer case with 4L. I have one on order now.

80% of the people that have 4x4 will never use. And when they do.. they will use 4H ..or "auto" most of the time.

I have a Sierra 4x4 and Silverado 4x4 and I'm in the woods every single week... and even I rarely ever need or choose 4L

Yup, Just to have something that adds complexity, cost and future problems for something your not going to use? There are going to be a few no doubt....I agree hardly ever use it?

newdude · September 7, 2018

The single speed t-case has an extra button on the shift control that uses the ABS/Stabilitrak to mimic 4LO in situations where it might arise.

If the 2 speed case is on anyone's requirement list, its included with Z71, which is available on WT, LT, RST, LTZ and High Country, and standard on Custom TB and LT TB. The only trim that you can't get Z71 on is the Custom trim.

rkj__ · September 7, 2018

6 minutes ago, newdude said:

The single speed t-case has an extra button on the shift control that uses the ABS/Stabilitrak to mimic 4LO in situations where it might arise.

If the 2 speed case is on anyone's requirement list, its included with Z71, which is available on WT, LT, RST, LTZ and High Country, and standard on Custom TB and LT TB. The only trim that you can't get Z71 on is the Custom trim.

I'd be interested to hear more about that 4lo mimic button. Any video reviews yet?

SILVER SLED · September 7, 2018

I've used many boat ramps in my life and only a few times have I needed 4wd, never 4wd low. Most of the people who talk to me about 4wd low tell me how they can't get it out of 4wd low once in 4wd low.

Darmichar · September 7, 2018

23 minutes ago, SILVER SLED said:

I've used many boat ramps in my life and only a few times have I needed 4wd, never 4wd low. Most of the people who talk to me about 4wd low tell me how they can't get it out of 4wd low once in 4wd low.

Same here. I use 4L every time I put the boat in or out of the water.

shift_grind · September 7, 2018

42 minutes ago, Darmichar said:

Same here. I use 4L every time I put the boat in or out of the water.

He said he never uses 4 low, only 4 hi.

I'm in the same group. It was necessary with the 4 speeds but you shouldn't need 4 low to pull a boat out with a new 8 or 10 speed (around 4.6 1st gear, 4 speed was 3.06)

I'd take 4 low, but I don't really care 1 way or another.

The single speed has a mode that has some cool off-road features like a crawl mode and a mode that makes it so the truck won't move unless your foot is on the gas (won't roll if idleing or when you take your foot off the gas or brake)

Sierra Dan · September 7, 2018

1 hour ago, SILVER SLED said:

I've used many boat ramps in my life and only a few times have I needed 4wd, never 4wd low. Most of the people who talk to me about 4wd low tell me how they can't get it out of 4wd low once in 4wd low.

Depends on the boat ramp.

Several around here in the KC area are STEEP and slimy.

4 Low is added insurance if you ask me. Kind of like the afterburner on a Jet Engine.

shift_grind · September 7, 2018

2 minutes ago, Sierra Dan said:

Depends on the boat ramp.

Several around here in the KC area are STEEP and slimy.

4 Low is added insurance if you ask me. Kind of like the afterburner on a Jet Engine.

Perhaps I'm missing something. If you're in 4 hi on a single speed transfer case and can spin the tires (you said slimy) you would have a gaurenteed 3 tire spin due to the rear locker. What would 4 low do for you? The single speed offers a mode that would make it so the brakes would stop you from rolling backwards when you are not touching the brake or gas too.

Sierra Dan · September 7, 2018

2 minutes ago, shift_grind said:

Perhaps I'm missing something. If you're in 4 hi on a single speed transfer case and can spin the tires (you said slimy) you would have a gaurenteed 3 tire spin due to the rear locker. What would 4 low do for you? The single speed offers a mode that would make it so the brakes would stop you from rolling backwards when you are not touching the brake or gas too.

I guess you are not missing anything but expressing your facts and opinions about what you know, which is what I have done.

The post I quoted from Silver Sled mentioned never needing 4wd Low for boat ramp use.

Like my response stated..... it would depend on the boat ramp. I have neighbors, friends and relatives who do use 4 Low around here on boat ramps.

I have also used 4 Low with my sierra on a boat ramp to launch and recover my next door neighbors 23' Tige' ski boat.

4 Low is a grunt/gearing aid in this case. Just like running 4 Hi or 4 Low in Mud. You need 4 Hi in mud for wheel speed. 4 Low will bog you down as you do not get the proper momentum.

rkj__ · September 7, 2018

24 minutes ago, Sierra Dan said:

I guess you are not missing anything but expressing your facts and opinions about what you know, which is what I have done.

The post I quoted from Silver Sled mentioned never needing 4wd Low for boat ramp use.

Like my response stated..... it would depend on the boat ramp. I have neighbors, friends and relatives who do use 4 Low around here on boat ramps.

I have also used 4 Low with my sierra on a boat ramp to launch and recover my next door neighbors 23' Tige' ski boat.

4 Low is a grunt/gearing aid in this case. Just like running 4 Hi or 4 Low in Mud. You need 4 Hi in mud for wheel speed. 4 Low will bog you down as you do not get the proper momentum.

My owners manual for my Sierra says you can use 4L up to 45 mph! Wow. The only time I tried 4L for more than 10 mph was on sand dunes in my Canyon, and I quickly concluded 4H was better suited.

Edited September 7, 2018 by rkj__