4 Lo And 1st Gear

[flynhigh]

Well one thing I noticed during my off-roading adverture this weekend was that when you are in 4lo and 1st gear there is almost too much torque to try and control. My heart jumped out of my chest the first time I tried that combination and gave it some gas. I probably could have climbed a vertical wall if the rubber was sticky enough.

SO my quesiton you guys is

How many of you have had the pleasure of 4lo and 1st?? and what were you doing at the time?

 

[jstrickl]

I only used it in the snow back in March after I took delivery. I just wanted to be sure all the 4wd parts worked fine. My 95 Grand Cherokee LTD and 99 Expedition XLT were exactly the same. You put them in 4-lo and as soon as you let off the brake, it wants to leap! In drive, you'll probably never get above 20-30 MPH as you'll tach-out (redline) the motor.

Jamie

 

[Crexis]

Been in 4-lo/first gear several times off road. Of those times, I probably only actually needed it once or twice. Used it to great effect going down a long rocky grade. Just let off the brake and the truck crept down over the rocks smooth as silk.

Also used it getting the front end to climb a pretty significant boulder... in 4-hi I could probably do it but was afraid I would give it too much gas (to get the RPM's up) and then slide over the other side of the rock (which I did not want to do). In 4 low/first it crawled up the rock at a smooth easy pace.

 

[dgalarne]

In drive, you'll probably never get above 20-30 MPH as you'll tach-out (redline) the motor.

Jamie

Actually, you could in theory hit 46 MPH in third gear at 5000R RPMs with a 3.73, and in the overdrive, you could hit 66. See table below. Again those are straight numbers calculated from final drive ratios in "crawl mode" or 4lo (based on a 5.3L V8 trans. info, and 2.72 crawl ratio for the transfer case).

3.73 4.1
first 15 14
second 28 26
third 46 42
overd 66 60

 

[jstrickl]

I guess I was wrong - thanks for the correction. That's how I recall my Expedition behaving. Guess I never went any faster than that as the engine was really winding up at about 20! I just assumed (sorry folks) that was it. I guess I'll have to do some SERIOUS experimenting this winter

Jamie

 

[dgalarne]

Jamie, I agree with you, the engine rev alone are enough to stop me also. I have no idea what the numbers would be for an expedition, but they sound pretty close to the AV (18 vs 20 mph in first gear). The only time I actually drove in crawl mode and the transmission shifted to second, the lurch forward was such that I never tried it again (this was with my 99 Blazer). I don't know if this is something that is recommended? Maybe one of the experts here could help us.

 

[flynhigh]

I spent most of the day in 4lo and 3rd gear. Seemed to be doing around 2500 rpms in the 20-30 range. Was a good combination for light to moderate offroading.

I only had to go to 4lo and 1st in the tree sequence. Pictures really do not do that area justice as it was much more gnarly then it looked.

 

[pdxkevin]

The 2nd weekend, we took it camping and I had to check out the gearing to make sure it was all working. Right?

So I found a suitable power line road in the forest and followed it. I bend the trailer plug at the initial climb. It crawled up in 4 high fairly easily. Found a steeper section, put it in 4-lo and away we go... It crawled up without a single slip, spin, or slide. Most watching would say it was boring. If you didn't know it was sloped you would swear I was slowly driving over a flat field. Out the front all you saw was blue sky. Now picture this is in an area of +100 foot tall pines out in the Pacific Northwest forests.

I turned around at the top and started on down. The view out the front went from a spectacular view across a couple valleys to the valley floor to only the bottom of the hill. It crawled down as smoothly as it went up. Even made several small 's' swerves as we went down to avoid areas that had washed out or had large exposed rocks.

At the bottom, I turned to depart at about a 30-40 degree angle. Smooth and no digging in of the hitch or trailer plug.

Not long until I can be back out on the trails.

 

[marc_w]

I used it once or twice in the dunes to make sure it was there...

I used it all the time in the ZR2 Blazer when offroading. ?Even in the winter, one of my most favorite things to do, (besides the powerslides and donuts), was to drop it into 4LO in an empty snow covered parking lot, in "D", and just "matt it". ?

The truck would "light up" all four, and the thing would blow through all four gears like I had a thousand horsepower under the hood. ?It'd walk sideways or claw it's way around in circles all day long... ? ? ?

So_Much_Fun! ? ?

 

[gandolphxx]

Good grief, after reading this thread, I may try 4LO at the track

 

[marc_w]

Gxx - there is a guy over on ZR2.com who put a LS1 in his pickup... He races in the sand, out at some famous dune/offroad area.

If I remember correctly, they race uphill, and use paddle tires... He says he uses 4LO when racing, as the truck maxes out around 70-75mph with something like 6500 on the tach.

 

[Blueruck]

I CO I use 4lo all the time. I get up to 12K above sea level and given that an engine loose roughly 3% of it HP for every 1K in elevation gain, I need the power to crawl over step areas and bigger rocks.

It also works great going down hill, to keep you off the brakes. You know it is steep when you are in 4lo, 1st gear and having to push the brake pedal through the floor to keep the AV in control

It is also fun to punch the gas in 4lo and 1st when you have 1st time riders - you should see them smile once they figure out what just happened

 

[Boar-Ral]

When I first purchased my Avalanche, I was bored and switched to 4LO to see if I could do it. I didn't need it at the time - I was just going over the parking stall barriers at the supermarket, traversing their parking lot in that fashion, in winter. It was still fun though. Until I pulled out onto the street, still in 4LO, and was lurching down the road, praying for no red lights. Which of course I got. It was still fun though.