If I am driving in high range, the brakes work fine at high speeds and when coming to a stop.

If I put the truck in low range and creep along, the brakes feel really weak and I have to stand on them to get the truck to stop. There is also this bump/catch/jerk as the truck nears a stop. It kinda feels like a downshift or the brakes grabbing.

Anyone have any ideas on what is causing this? It makes things scary when off-roading.

(Brakes have not been bled in a while. No lights, no codes)

 

In low range your vehicle is putting more power to the wheels. If you're in low range, you can let off the brake and climb up some hills, in high range this is not possible. Your brakes will feel weaker by comparison.

 

The bump/catch/jerk is probably the trans downshifting. Try using manual mode and see if this stops.

And yes, it's not that the brakes are weaker, just you have far more torque at your wheels in low range.

A full brake flush is a good idea if you aren't sure of the last time it was preformed, or has been over a couple years.

 

Bob, my D1 does the same exact thing. I am in need of some new rotors and pads however.

 

Anybody know how much torque they put out in low? Be interesting to know?

 

Well that explanation just makes too much damn sense . Glad to know it's not actually a problem.

 

You make the same amount of torque in high or low, just gets further multiplied by gear reduction in the t-case in low.
So in any given gear, you have about 2.74 times the torque to the wheels in low then you do in high.

 

Take engine rated torque at the flywheel that they advertise in foot pounds (youll need to see a dyno'd graph of the curve to see the output at each rpm, or use the advertised torque at the peak rpm it lists which is 250ft pounds at 2600rpm), then account for the transmission gear ratio, the transfer case gear ratio, differential gearing ratio, and tires radius (or distance to the pads if you wanna know whats pushing against the rotors lol) to calculate the pounds of torque its capable of putting to the ground. ps thats without engine loss from age, friction, drive train slack, rotational/inertial losses, tire flex delay etc. lol

 

I would do a brake inspection and see if you can gain any stopping power there with maintenence, but X2 on the extra torque in low argument. These trucks dont make a lot of HP, but they make pretty decent amount of torque. Especially in LOW range. All that torque couple with the shear weight of these trucks makes stopping into a pretty big task for the braking system. Try knocking the truck into NEUTRAL when braking. I do this if I have to make a really short stop and seems to cut my braking distance down about 25%. Nice trick to know if you need to stop short, but would rather not squeal the tires and scare everyone to death.

 

The low range torque argument would only apply if you're applying power while braking. If you take your foot off the pedal and apply the brakes the engine should be trying to idle and so be sending very little power to the wheels.