crd 4x4 system

les234 · Posted: Mon Jan 14, 2013 11:03 am Post subject: crd 4x4 system

I have recently changed the tyres on the cherokee crd to m/s tread, so more aggressive than the dunlop roads.

On the road tyres it skiped along the fields just nice , without too much power on. With the m/s tyres it gets stuck !!!!!!

I was stuck in the field & decided to climb out whilst it was in gear & the wheel turning to shove the B***std out, & noticed the rear driver side spining in the cr*p, but no other wheel ??? I thought the idea of these systems was to transfer the power/grip to the wheel with most traction ?? Hmmmmmmm am i wrong ,or is there something wrong here .. ??

thanks

jonny jeep · Posted: Mon Jan 14, 2013 6:34 pm Post subject:

I'm going to have to ask since only one wheel was spinning. Were you in 4WD? Regardless of that, if no drive was going to the other rear wheel you either have an open rear diff, or your limited slip isn't working.

With an open diff the same amount of torque is applied to both wheels. Since you had a wheel spinning there is practically no torque at that wheel so you get no drive from the other wheel.

One thing you could have done instead of getting out is to increase revs to 3k or so and with your left foot stomp up and down on the brake pedal. The braking of the spinning wheel means torque is applied to that wheel, the same amount of torque is transferred to the wheel with grip and you should hopefully get moving. That may not be the best explanation of how it works but it'll have to do.

longship · Just got MTs Joined: 05 Jun 2010 Odometer: 114

Depends on whether you have an open or LSD type diff. Open diff will do as you describe. If you have a LSD type, try putting the handbrake on gradually, I've heard that can help.

Were you in 4wd?

Rob

The Smiths · Posted: Mon Jan 14, 2013 6:39 pm Post subject:

needs to be 4wd, with centre diff lock - then you get stuck with one front and 1 rear spinning

les234 · Posted: Mon Jan 14, 2013 6:55 pm Post subject:

Thanks for the replies......

oh yes 4x4 was on, the lever up p/t 1st notch.

I have recently changed all the oils in the g/box diffs tramsfer etc, could there be an air lock some place ?? Question

daggie · Posted: Tue Jan 15, 2013 7:15 pm Post subject:

it has open diffs front and rear !
unless its a quadradrive Wink

scotty wong · Posted: Wed Jan 16, 2013 6:25 pm Post subject:

Dose it have part time and full time 4wd written on or near the transfer lever? If so what were you in? Mud and snow dont really mean much what tyres do you have? M/s is just a rating so they have passed a minimum catagory and will work in snow.... a bit.

les234 · Posted: Thu Jan 17, 2013 2:00 pm Post subject:

Thanks for the responce..

The jeep was in part time, & then tried full time ..but gearing too low in f/t. I placed it in p/t 4x4 mode, it should have ****** through the mild mud, as it was only 2" !!!

The previous terrano i has would do axle dept, with these tyres on.

scotty wong · Posted: Thu Jan 17, 2013 6:36 pm Post subject:

What tyres are they what pressure are you running what profile.i have had a v6 in mud on road tyres and was great,it dobt have electric crap to do it for you so you have to drive it out but its easy.

les234 · Posted: Thu Jan 17, 2013 9:24 pm Post subject:

245/75 x16 running @ 32 lb pressure or less (26/28 ) in the cr*p..& tyres are Pirelli scorpion. 50/50 pattern

les234 · Posted: Mon Mar 25, 2013 4:17 pm Post subject:

It seems you have to have 3000 rpm + for the 4x4 system to be efficient & the 4x4 engages & it climbs thru whatever . It snowed here 4 ft y'day & I aint had any problems it just climbs thru the white stuff with ease.

thank goodness Laughing