Brake based limited slip differentials

[Stinnett21]

I think mechanical limited slip differentials are becoming a thing of the past. Most today are electronic brake-based. Can anyone with a 2WD truck with a brake-based limited slip share their experience on boat ramps? I'm considering such a buy in the future to tow a 4000 lb. rig.

 

[airshot]

I would never use a two wheel drive on a slippery boat ramp with a 4K boat, that is an accident looking for a place to happen......

 

[Pmt133]

I've always had 4wd. I've never needed 4wd to get a boat up a ramp. My 04 had an open diff and was never an issue. Our ramps aren't very steep though.

 

[Stinnett21]

I've always had 4wd. I've never needed 4wd to get a boat up a ramp. My 04 had an open diff and was never an issue. Our ramps aren't very steep though.

Same here. I've had auto 4WD for many years and to my knowledge it has never kicked in. However, I'm inland on river and lakes where there's no tidal waters covering ramps twice a day and keeping them slimy. Most ramps where I'm at (Lake Cumberland) are ripped concrete.

 

[Pmt133]

Same here. I've had auto 4WD for many years and to my knowledge it has never kicked in. However, I'm inland on river and lakes where there's no tidal waters covering ramps twice a day and keeping them slimy. Most ramps where I'm at (Lake Cumberland) are ripped concrete.

Mine are sandy dead end streets mostly lol. There aren't a ton of public ramps local to me and even fewer are "free". I'm not paying either 40$ a pop to launch or 200$ for the season when the free ones are adequate.

My current tow rig has a gov lock rear end and 4wd so it is fine. The other vehicle I towed with was AWD but used the abs system to make a pseudo limited slip and direct torque to axles.

 

[Chris1956]

The way I understand the "Posi-traction" limited slip differentials of the 70s and 80s, was that they often had mechanical breaking on the wheel that slips.

 

[Lou C]

Brake activated traction control can work on level surfaces but not so much on a slope esp pulling a load. My 2007 Grand 5.7 had the Quadradrive 2 system which included electronic lockers in the rear & front. Excellent traction in all conditions. With GY Duratrac tires & 330 Hp & 375 ft lbs of torque this thing is nearly unstoppable. That said my old 98 Jeep with Selectrac was fine on the ramp too. Here 2wd would be risky. Ramp is slimy & we have 6 foot tidal swings.

 

[Scott Danforth]

Limited slip diffs use a spring pack and clutches in the diff. Some clutches such as the getrag units are internal and external discs. Some are just plates against the spider gears.

The Eaton unit uses two flyweights that fling out and catch a pawl when one side starts to slip (they often explode)

Torsen units use a bunch of helical gears

Chrysler sure grip units use cone clutches

Applying a brake to the slipping side can work in limited circumstances, just adds wear to the brakes

No replacement for true limited slip differentials

 

[airshot]

I've always had 4wd. I've never needed 4wd to get a boat up a ramp. My 04 had an open diff and was never an issue. Our ramps aren't very steep though.

I only use 2wd on most retrieval, but the 4wd is there if needed.... and it has been needed on a few ocassions!! Water has been low this season, really low this fall...ramps are like ice, many can't get traction with 4wd...at season's end we are seeing a number of folks using two vehicles to pull up the ramps. With a 4K# boat...I would not chance a 2wd only.

 

[Lou C]

shallow ramp with slime, roller trailer needs to be in deep to get boat on/off, 4x4 is a must, and electronic lockers make it easy + 330 hp & Duratracs.
this is my local ramp at the private beach assn. about 1/4 mile from my house, the town ramp about 5 miles away is a nice deep and steep and wide ramp, so there you could probably use a 2wd, at least at high tide.

 

[Pmt133]

I only use 2wd on most retrieval, but the 4wd is there if needed.... and it has been needed on a few ocassions!! Water has been low this season, really low this fall...ramps are like ice, many can't get traction with 4wd...at season's end we are seeing a number of folks using two vehicles to pull up the ramps. With a 4K# boat...I would not chance a 2wd only.

Have and not need is much better than need and not have.

 

[FLATHEAD]

View attachment 412835
shallow ramp with slime, roller trailer needs to be in deep to get boat on/off, 4x4 is a must, and electronic lockers make it easy + 330 hp & Duratracs.
this is my local ramp at the private beach assn. about 1/4 mile from my house, the town ramp about 5 miles away is a nice deep and steep and wide ramp, so there you could probably use a 2wd, at least at high tide.

Reading your endorsement of Duratracs. I had a set of Duratracs on a 4WD truck. Had high hopes for them. They didn’t wear very well. Got noisy and fast tread wear. I was disappointed with them.

 

[Lou C]

They do wear fast. And at least on Jeeps need to be rotated every oil change or so

 

[jimmbo]

Brake based Limited Slip Differentials are also known as Traction Control.

I will take a LSD over Traction Control any day, though if it took enough of the other LSD I might find Traction Control entertaining... though years from now, a Flashback would be scary

 

[bruceb58]

In all my years of towing, I have needed 4WD once at a ramp and that was when the trailer axles fell off the edge of a ramp caused by people that power loaded.

I have used electric locking rear ends and 4WD a lot because we own two vacation homes in the mountains

 

[Lou C]

Coastal regions = 6’ tide swings + salt water which leaves slime on the ramps. You have to be careful just walking on it!

 

[bruceb58]

Coastal regions = 6’ tide swings + salt water which leaves slime on the ramps. You have to be careful just walking on it!

Same here...never needed 4WD at a saltwater ramp but we do have nice ramps.

 

[airshot]

We have nice ramps for the most part, but having a good quarter inch of green slime covering the ramp for the length of your tow vehicle makes the nice ramp not so nice. Steepness is a big factor, I have watched big dual wheel trucks burning rubber trying to pull 6K boats up these ramps, each ramp can present different challenges. While I don't often use it, I would not be without my 4wd just in case !

 

[Lou C]

Funny thing is that the steep and wide town ramp, is way less slippery than my shallow more local (1/4th mile) ramp. Gotta be careful when stepping off the trailer after recovering the boat. At least our local beach assn finally put in a new ramp the old one was tough on tires so much so that I kept using bias ply tires on the trailer because the sidewalls are stronger than radials. A few people blew tires on the old one! The new one is still shallow but much much better.

 

[Pmt133]

The ramp at the lake is steep. My girlfriend was in charge of parking the tow vehicle last time we went up there and she spun with the empty trailer going up. She just isn't used to that much power lol. On that ramp the truck stays dry. My normal ramps the back tires are in water to be able to get the boat easily on. That usually means the trailer fenders are about 3 inches above water.