RAM LSD in reverse?

[Bill2014]

So, last week I was slowly backing up in 2-hi and the driver side rear wheel went over a patch of ice. The truck stopped and the driver rear wheel continued to spin. I thought that was strange with the rear LSD - but the weather was shitty and I didn't have time to I investigate any further.



So this week, I noticed a patch of ice in the driveway and tested the rear LSD. Again, backing up in 2-hi, the driver side rear wheel got on top of the ice and began to spin. The truck came to a stop. I pressed on the brake and the wheel stopped spinning. I let off the brake, and the driver side rear wheel began spinning in reverse without even giving it any gas. I gave it some gas and the wheel would just spin faster. I tried both the brake and the gas together, but no combination of pressures would cause the truck to budge in reverse. I put the truck in drive, the rear driver wheel gave a small slip and the truck moved forward as the LSD worked in the forward direction.

Hmmm - is the RAM LSD supposed to do anything in reverse? Anyone else tested this?

[nts007]

This is really weird. I was backing up on ice and both my tires spun at all times. Wether or not one tire found traction. I only would get a little slip maybe 1/4 turn starting at a standstill then they would both lock up. Forward or reverse. I had to try to see if it was the same as you. Unless I can't replicate your exact situation. I was trying in a slight incline too. Also never noticed in snow that it would do that

[Will]

I tried to replicate this in my 2010 and mine spins both (Wet slick red clay, I assume as bad as ice) forward, reverse, doesn't matter, both rears spin.

[Bill2014]

Thanks for testing... Hmmm, I wonder if anything could be different with the AAM 11.5?

[usmc369]

Havent tried on ice but if I floor it in reverse I get two black patches.

[loveracing1988]

Thanks for testing... Hmmm, I wonder if anything could be different with the AAM 11.5?

Same exact helical lsd design.

[waldo]

I know the 3G LS works in reverse, but to be honest I haven't paid much attention to the new one when it comes to that.

[Bill2014]

More testing on ice this morning all in 2-Hi.

On pavement, with traction control off, both rear wheels spin together in forward or reverse. With one wheel on pavement and the other on gravel, again both wheels spin together in forward or reverse. (This is as I would expect)

Introduce smooth ice and everything is different:
With one rear wheel on smooth ice - shift into reverse and the wheel on ice spins backwards without giving any gas. Applying the brake slows and then stops the tire from spinning but does not help the vehicle to move at all. Shift into drive and the wheel on ice now spins forward without giving any gas. Hitting the gas quickly just spins the tire faster. The sudden engine acceleration does cause the truck to move slightly but it settles back into position with the wheel spinning faster. (I did not expect this behavior with the rear LSD). Had to put it in 4-Hi to move the truck at this point to test some more.

Back into 2-Hi and both rear wheels on smooth ice. Shift into reverse and both rear wheels spin backwards without giving any gas. Rear-end slowly slides sideways as both rear wheels slowly spin together. Shift into drive and both rear wheels spin forward together without giving any gas. (This is as I would expect). Had to put the truck in 4-Hi again to move it off of the ice.

So it appears that if one rear wheel has no traction at all, such as being on smooth ice or up in the air, then the rear LSD isn't going to do anything useful for you. I didn't expect this to be the case!!!

[azracer]

It is a helical LSD and this is why we need a locker.

Here are two versions. However neither is an exact representation of our trucks helical LSD.

phpBB [video]

Clickable link for Tapatalk

phpBB [video]

Clickable link for Tapatalk

[RustyPW]

Guys at the track don't like helical LSD's. If the inside tire lifts during a turn. All the power goes toward the lifted wheel. Killing your drive. I installed a Cusco Type RS, set-up as a 1.5 one way in my track car. If the inside tire lifts. It will still drive the car with the outside tire. Plus you can tune it.

[Colibri]

Cusco makes a good differential I have one in my track car as well! The lsd in our trucks biases torque, if no torque is present nothing happens. 0 X any number is still 0 so to speak. A clutch type lsd can be built with preloaded bias. I don't think a clutch type would last very long for our application though.

[nts007]

Cusco makes a good differential I have one in my track car as well! The lsd in our trucks biases torque, if no torque is present nothing happens. 0 X any number is still 0 so to speak. A clutch type lsd can be built with preloaded bias. I don't think a clutch type would last very long for our application though.

Not very well under high torque. Or ask gm how their fancy Swiss watch lsd works lol. Wait it doesn't. Cause it breaks in 99% of the trucks lol

[Bill2014]

*sigh*
I'm a little disappointed in the reality of the situation. Was kinda hoping that I had something wrong that I could have fixed. Wouldn't it be great if the trucks actually had a LSD that would work in a zero traction situation and hold up in the heavy duty trucks. Thank God we have the lockers for off-road!!!!

[azracer]

Here are two good options for a truck... Lock Right and the Detroit locker sadly I don't think either is available for the dodge. In reality our units are the best for towing and such while having the option to lock it electronically sure makes it superior in my book. The Detroit is not the best for towing because it can hang up and let on axle do all the work in some situations.

http://www.powertrax.com/

http://www.eaton.com/Eaton/ProductsServ ... it-locker/

[RustyPW]

I had a Detroit locker in a '90 Nissan Hardbody V6 4x4 with a 100" WB. Worked great off-road. Streets manners was something else. Going through a turn with the power on, it would push the front to the outside. Lift the gas, and it would pull the front to the inside of a turn. Coming out of a turn onto a straight. It lock up with a bang, and shake the truck. Going around slow speed turns. It would chirp the inside tire.

[azracer]

Yup that's why I went with the power lock in my ranger with a ford 9" using 600 gears. Spool does the same as the Detroit but the race truck had to have a spool. They say the Detroit soft lock is much better now but I have never used one.

[2wagons1driveway]

This is normal for a helical limited slip the dodge hd LSD sucks compared to some others...


Sent from Canada

[nts007]

This is normal for a helical limited slip the dodge hd LSD sucks compared to some others...


Sent from Canada

I'd disagree as your comparing to aftermarket. It's likely one of the best offered in any factory truck. Even Ford advertises a lsd but after a year or two it just stops working. I don't have exp with the imports but in the factory 3/4-1tons it's the best the factory offers

[Cactus Red]

From my perspective, the LDS does a fine job in our trucks. It requires no maintenance, uses standard gear oil, and is very unobtrusive in normal driving. It does provide traction in most circumstances, and when it doesn't, a simple push of a button locks the axle. I've found it to be reliable enough that other than severe crossed axle articulation, deep snow, sand, or mud, the locker is rarely used. Heck, even with as much 4X4 time as we do, I'd say the lockers are only used a few times a year.

My experience with Detroit lockers is limited to my Toyota trail rig. I broke both front and rear lockers on Outer Limits at the Hammers the same day. And on pavement, they sucked with a 5 speed. Went with dual spools after that.

Socialism: A stage of society in Marxist theory transitional between capitalism and communism and distinguished by unequal distribution of goods and pay according to work done.

[RustyPW]

The LSD in my 3G works great. Alot of times. I never lock the locker. It will spin both wheels in both directions.

[Will]

I like it. It works perfectly in my opinion and like said, we have a true locker to back it up. I suppose ice would mimic a lifted tire as far as resistance. The only time I've had "one wheel spin" is when articulated far enough I lift a tire, then it will spin freely. I wouldn't want anything else, especially when towing, I'd tear something up for sure then. It is what it is, Limited Slip, not Zero Slip.

[waldo]

I like it. It works perfectly in my opinion and like said, we have a true locker to back it up. I suppose ice would mimic a lifted tire as far as resistance. The only time I've had "one wheel spin" is when articulated far enough I lift a tire, then it will spin freely. I wouldn't want anything else, especially when towing, I'd tear something up for sure then. It is what it is, Limited Slip, not Zero Slip.

Yeah, I can't complain about the LS in my 07. I live in snow country and it does well. Got caught in some real ice storms over the years. Bad ones where you had to straddle the crown of the road to keep from sliding off into the ditch bad. Truck would still go forward.
I haven't driven the 16 on real ice though, just slush and snow.

[2wagons1driveway]

It's Deffinately better than no LSD


Sent from Canada

[RAM4ROKS]

We don't get much ice or snow here but, I have never noticed my LSD doing anything with throttle other than spinning both tires. (except when the TC cuts in too much and won't let it spin tires at all) Dry pavement, wet pavement, mud, etc, both tires spin. I cannot comment on your exact circumstances though, as I don't recall ever having reversed with one tire on pavement and the other on ice so....?

[Will]

Here you go, left rear jacked up just enough to clear concrete, left off brake it it spins.

https://vimeo.com/158541546