After driving my truck for 1/2hr, I put it in 4 Lo to pull it up on ramps and as soon as it went into gear, D or R, I had to fight the truck moving with full brake pressure. No RPM increase, just idle. 2 days ago, I changed the trans pre-filter, replaced lost fluid and checked fluid level after a 40 minute trip. I backed up our 5th wheel in 4 Lo later that day and didn't notice the problem. 4 Hi is normal. Is this something with the torque converter?

I'm not following you...

Was it necessary to use 4-Lo? I know if you try to use 4-Lo on dry pavement you will get a lot of feedback in the steering wheel, especially when turning because you're putting your drivetrain in a bind and something needs to slip. I guess that would be a "fight." Not to slight you in the least, but my guess is that there is nothing wrong. What I think you are describing is commonly reported among those who are not familiar with a transfer case with no differential.

I'll wait to hear what one of the local experts say.

T-Rex
I was only using 4 Lo to pull up on ramps. 2wd just pushes them through the garage. 4 HI doesn't start to move as easily, then it takes off. I just changed front diff fluid and compared 2wd, 4HI and 4 Lo. There is definitely a difference between HI and Lo, but I believe that I (FNG) just didn't know how much pull/push Lo would give. I'm curious to know if everyone else finds the same with their 4wd.

Same with mine. You have to hold-er back. With the big
power, and the low raito, it's a bit of a scare in 4 LO.
But, man it goes when you need it!!!

Yeah, you've got some serious torque multiplication in 4-Lo. Just imagine what it would be like if the gear ratio was something like 4.3:1 lor a 5:1 like with an Atlas x-fer case compared to the stock 2.72:1.

I put my truck in 4-Hi in the driveway to rotate the tires because the front differential is open. As soon as I'm done the wife comes out to make a run to the store. Minutes later she comes in saying something is wrong like I screwed something up. The deal was she did not put it back into 2-Hi before she tried to go and so when she turned the wheel she got some serious feedback and binding as if the truck could not move. It was simply operator error on her part and she knew better because she used to drive a Jeep.

Anyway, you might want to try using the brake and the throttle--apply a little pressure to the brake and feather the throttle to use 4-Hi to pull up on the ramps. 4-Lo is for more extreme conditions.;)

They should print something in the manual and on the dash about the lack of brakes in 4x4 LOW. No other truck I have owned has shown this trait. It is scarry the first time you experience it. For me, I was backing down a hill on the job site with a load of 12" valves to unload and just about killed a coworker. He was standing behind the truck guideing me and the excavator was behind him. Had to put it into neutral to stop. thanx geo.

not lack of brakes..... just massive torque multiplication. In reverse with 3.73 rear gears it's something like 41:1(lo range),in Hi(or 2wd) it's about 15:1. Now add the engine torque multiplication factor from the torque converter, viola! Lots of pull

Whatever, the Allison is the only tranny that i have driven that doesn't unlock enough at idle. Scary! thanx geo.

The first time I tried 4 Lo, I about filled my pants! I was on a soft terrain and decided
to stopped and had to just about put the pedal to the floor! That is just massive torque, not a problem.


01 Ext. 107,000 miles 4X4, Edge with attitude, K&N

Haven't tried mine yet (don't know why):confused:. Tomorrow may have to be the day! :rolleyes:

I thought I read some place that the brakeing (antilock) is tied into the tranny somehow so that while in 4x4 the grade breaking won't lock up the wheels on ice. Possibly this is the reason for the difficulty in 4x4low with the brakes. Can any one confirm this? The last 15 trucks I had where 4x4 standards and lots of torque, and I could lock up the wheels in 4x4low and stall the engine, especially in marginal traction. thanx geo.

I have never had that problem with mine but it does want to go when in reverse. You can cure the sliding ramps two ways. The best is to give the metal ramps away and buy a set of the Rhino brand composite. They contact the floor full length and have a rubber pad on the bottom. I had the same problem with my steel ramps. I bent one and went shopping for a new set. I found that most steel ones weren't heavy enough. The Rhinos are heavy duty. Later! Frank