Limited Slip or Open Differential?

RussOnTheRoad wrote:
As the OP I want to thank everyone for thier contributions to this thread. I also want say that yesterday I pulled the trigger and ordered a 2017 Ford F350 diesel dually 4x4 with a 3.55 LSD.

Congratulations!

As the OP I want to thank everyone for thier contributions to this thread. I also want say that yesterday I pulled the trigger and ordered a 2017 Ford F350 diesel dually 4x4 with a 3.55 LSD.

transamz9 wrote:

Chuck_thehammer wrote:
OPEN differential is a single wheel drive.. or single axle drive in the duelly..

poor traction in rain,mud,snow,ice.

once THAT one wheel starts to slip.. only way to get the other wheel to power is using the parking brake..( this does not always work )...

OR have traction control.....

having three vehicles with traction control, I'd say they vary noticeably in how the react and how effective they are. the GMC is the least intrusive, but the downside is it is marginal in respect to stopping spinning. and of the 3 vehicles the least improvement in getting moving. I wish GM had at least given a mode of starting in 2nd gear along with traction control

another of our vehicles is so aggressive it barely will spin, then bogs noticeably. It's very effective but can have a annoying and somewhat unsafe bog when it engages.

the third couples with allowing a wet or standard operating mode. I call it wife and self. but in the wet mode it starts in second gear, ******* ignition timing, and short shifts under acceleration, shifts from 2nd to 3rd at maybe 15 mph. and couple that with traction control. In reverse it changes gearing as well to effectively have reverse like 2nd gear forward. And when sensing wheel slip it ******* timing more and reduces throttle at the same time it applies brake to the slipping wheel.

this rear wheel drive car with summer tires has gone around or got started on hills where those with awd and studded tires couldn't get moving.

IMHO traction control is better called poor man's posi and the first step in helping. Next step up is traction control and some form of posi, then an autolocker like the Eaton G-80 on GM vehicles, followed by a manual locker.

Terryallan wrote:

LIKE2BUILD wrote:

RussOnTheRoad wrote:
I'm looking at the 2017 Ford F350....DRW, F350 diesel is a non-limited slip 3.55 ratio....options are a limited slip 3.55 or limited slip 4.10. Locking differentials are not offered on the DRW.

What I am wondering .....if the LSD makes sense. It's an extra $350 to buy the LSD and I hear they need more maintenance.

If the truck is 4X4 you can probably get by with an open diff since you can compensate for poor traction with the front axle. If you're getting a 2WD, then an LSD is an absolute must.

My previous truck came with an open diff. It was basically a one wheeled wonder on wet grass, slight inclines, and wet boat ramps. Let's just say that axle did me no favors in controlling my anger. I later installed an Eaton LSD and it made a world of difference. I could still get stuck on wet grass on an incline, but boat ramps and most other typical slick conditions were now passable.

One of the reasons I got my current truck was for 4X4. I got stuck in a wet campground in 2015 and that was the last straw. In that situation 4X4 was the only solution and I didn't have it. If I were to ever own another 2WD it will definitely have an LSD or electronic locking diff. Believe me, the $350 you'll spend on an LSD will be more than made up the first time you encounter slick conditions. More than likely the LSD will get you through where an open diff will leave you watching the tire with the least grip spin like a treadmill.

KJ

Just asking, Cause I'm not sure. I know how the old ones work, just not sure about the new ones.
However IF the axles are NOT Limited slip, and you then put it in 4x4 would you not only have one front wheel, and one rear wheel pulling? Where as if it was a limited slip. they all would kick in if traction was lost????

Also on my ford. I have a selection that locks up the rear axle, for emergency traction.

As for traction control. Not impressed. Seems to only pull back the throttle until it stops spinning. I can do that my self, and in a much safer way.

The traction control on my truck applies brake pressure to the wheel that is slipping causing the other wheel to pull.

Chuck_thehammer wrote:
OPEN differential is a single wheel drive.. or single axle drive in the duelly..

poor traction in rain,mud,snow,ice.

once THAT one wheel starts to slip.. only way to get the other wheel to power is using the parking brake..( this does not always work )...

OR have traction control.....

No e locker on the dually? That's too bad. Nice feature.
With 4x4 a posi rear is not as necessary but I'd still get it.

The way. People are talking on here leaves the impression that an open differencial is a single wheel drive....It isn't. With an open diff the power is split between the two rear wheels. If both wheels are on a similar surface you have two wheel drive. The locket comes into play when one wheel has better traction than the other.

These were GM trucks, which has the best LS/Locking rear end of the big three. My 88 K3500 with an open diff was useless in rwd, did better in 4wd. My 96 sw 3500 crew cab and the 05 dually had the G80 locker. I went places in rwd the 88 needed 4wd. Including pulling local passes in rwd when chains or 4wd were required! Got thru mud and wet grass in rwd.....rarely needed 4wd in a generally speaking term. Had the g80 in an 89 Astro van too, compared to the 2000 awd no g80. Both did fine in snow etc. But the 89 did well with correct tires. worst case, throw chains on it, it was keeping up with the 88, 96 left it behind for the most part.

I personally for most of how I drive, would take a locked rwd over an oven 4wd. There are times a locked rwd will out do an open rear 4wd, and vice versa. A locked 4wd is best.

As far as axel ratios go.....I'll take the lowest I can ALL the time. Lower gears get you up steeper grade before stalling out! Even with the newer transmissions with lower gears vs older one, better to have the too low option vs too tall for towing, but better mpg empty. Then again, I'vebeen stalled out on 15-20+ percent grades locally enough that I go full tilt toward torque multiplication to tow up steeper grade.

marty

LIKE2BUILD wrote:

RussOnTheRoad wrote:
I'm looking at the 2017 Ford F350....DRW, F350 diesel is a non-limited slip 3.55 ratio....options are a limited slip 3.55 or limited slip 4.10. Locking differentials are not offered on the DRW.

What I am wondering .....if the LSD makes sense. It's an extra $350 to buy the LSD and I hear they need more maintenance.

If the truck is 4X4 you can probably get by with an open diff since you can compensate for poor traction with the front axle. If you're getting a 2WD, then an LSD is an absolute must.

My previous truck came with an open diff. It was basically a one wheeled wonder on wet grass, slight inclines, and wet boat ramps. Let's just say that axle did me no favors in controlling my anger. I later installed an Eaton LSD and it made a world of difference. I could still get stuck on wet grass on an incline, but boat ramps and most other typical slick conditions were now passable.

One of the reasons I got my current truck was for 4X4. I got stuck in a wet campground in 2015 and that was the last straw. In that situation 4X4 was the only solution and I didn't have it. If I were to ever own another 2WD it will definitely have an LSD or electronic locking diff. Believe me, the $350 you'll spend on an LSD will be more than made up the first time you encounter slick conditions. More than likely the LSD will get you through where an open diff will leave you watching the tire with the least grip spin like a treadmill.

KJ

Just asking, Cause I'm not sure. I know how the old ones work, just not sure about the new ones.
However IF the axles are NOT Limited slip, and you then put it in 4x4 would you not only have one front wheel, and one rear wheel pulling? Where as if it was a limited slip. they all would kick in if traction was lost????

Also on my ford. I have a selection that locks up the rear axle, for emergency traction.

As for traction control. Not impressed. Seems to only pull back the throttle until it stops spinning. I can do that my self, and in a much safer way.

OPEN differential is a single wheel drive.. or single axle drive in the duelly..

poor traction in rain,mud,snow,ice.

once THAT one wheel starts to slip.. only way to get the other wheel to power is using the parking brake..( this does not always work )...