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Limited Slip - Best for Tread Lightly?

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JeepFever View Drop Down
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    Posted: 22 June 2022 at 11:39pm
Nothing too exciting here,  but some thoughts on "locker" type.

Today,  Wilson was pulling a Bantam trailer-load of dirt in a somewhat awkward situation.  The trailer had probably 800lbs of dirt,  trailer tire pressure at 12 lbs, in soft dirt, so not an easy pull.  Not sure how much force it was to pull, but somewhat high.    Wilson was backed down a slight slope, and rear passenger is dropped over a 14" rounded dirt "step".   This put it into a "crossed-up" situation of light down-pressure on passenger rear.
I wanted to "tread lightly" and not spin tires,  so was going to put in 4wd,  but thought I would see what happened in 2wd.  To my surprise,  it pulled out with ZERO tire spin.

My guess:
If rear was open,  then the passenger tire would have spun hopelessly,  requiring 4wd
If rear was selectable and locked,  it would have made tire marks because of hard left turn that was necessary.
If auto-locker,  possibly driver tire would have spun until additional traction of passenger tire kicked in.

ie.  Limited slip might have been only locker type to leave no trace.  .   traction of passenger + 3x of that on driver was enough to pull out with no spin.

Photo does not really show the slope,  or the step too well,  but this was not an easy pull.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 8:13am
Are you questioning whether you have a limited slip?

Easy to find out, just put jack stands under both ends of the rear axle so both wheels are off the ground.

Turn one wheel by hand and tell us what the other wheel does.
If you can't get there in a Jeep you don't need to be there
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Mark W. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 9:20am
if they turn opposite directions you have an Open rear if they turn the same direction you have a Limited slip, or some form of locker
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jeff J Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 9:26am
Turning the trailer like that takes less effort than pulling it straight giving the jeep a head start on the full tow weight. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 9:34am
I like the limited slips more specifically the “Powr Loks” for several reasons.
I like them so much that every one of the last 12 axles I built had 
original Powr Loks installed.
They were specifically developed for Jeeps by Spicer for the US military,
No they are not perfect and certainly are not the best choice for any particular type of driving. They excell at almost nothing except they are of the strongest most durable design and by for the most versatile for mixed driving conditions. Plus no engagement is required. It’s fully automatic so you need not consider when to engage and when not. Handles every type driving condition well but no specific condition with excellence.
Ice, snow, liquid mud, paste mud, wet grass, loose rock, solid rock, slick rock and sand.
Plus dry pavement cornering at speed.




Edited by oldtime - 23 June 2022 at 9:38am
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Stev View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stev Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 9:48am
I have had okay results not leaving tracks in the woods, Silvopasture area, and fields with the CJ2A.  Ground condition and moisture content are big factors.  When it is very wet, it is difficult to leave not marks.  Try not to go into the fields when they are wet.  

I get the best results buy putting the Jeep in four wheel drive as soon as I leave the farm lane.  Gear selection needs to match the task at hand (not too fast or slow).  Select stopping locations that are high,  solid and level. 



 


Edited by Stev - 23 June 2022 at 9:50am
Stev
1946 CJ2A Trail Jeep (The Saint), 1948 CJ2A Lefty Restored
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2022 at 11:46am
My CJ5 has a Powr Lok in the rear and I am very impressed with it. That Jeep will go places in 2WD that requires 4WD in my CJ2A. I have a pair M38A1 Marine surplus axles that are going under the 2A the rear has the Powr Lok.  
If you can't get there in a Jeep you don't need to be there
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GeorgiaFlattie Quote  Post ReplyReply Direct Link To This Post Posted: 24 June 2022 at 1:10pm
If you do a mix of road and trails or mainly mild trails a PowerLok is a great option. If you primarily do hard trails with minimal/no road miles there are better options. In fact, I'm getting ready to pull the D25 with a PowerLok out of my 3A then swap in a D30 with a lockrite. Having a tire up in the air spinning when the other should be pulling is annoying. My rear axle is welded so I'm a fan of maximum traction at all times.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 24 June 2022 at 5:40pm
I went a different way open D25 and 30 spline flanged D44 with an Eaton E locker. Arming switch on the dash below the speedo and an actuater switch on the shifter. Did a little testing over Memorial weekend worked great.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeepsterjim Quote  Post ReplyReply Direct Link To This Post Posted: 24 June 2022 at 5:58pm
have power loks front and rear.  Installed Ford Fusion rear disc brakes with electric E-brakes which can be used as cutting brakes that  just might help in certain traction situations. 
Jim
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Nothing Special Quote  Post ReplyReply Direct Link To This Post Posted: 25 June 2022 at 8:26pm
I would not think that a Powr Lok, or any other clutch-type limited slip would be best at treading lightly.  Good.  Probably even second best.  But not best.

In most situations they will be better than most lockers (automatic or selectable).  Unless you are going in a straight line selectables guarantee you are going to scuff tires.  And unless you are going in a straight line an auto locker is more likely to spin a tire than even an open diff.

It would also often be better than an open diff which would be more likely to spin one tire than the Powr Lok would.

However a Powr Lok (or any other brand of clutch-type limited slip) will still spin one tire if it's not tight enough for the traction need.  And it will scuff a tire if it's too tight.

I think the best diff for treading lightly is a TrueTrac.  They will never scuff a tire (like a selectable will or a clutch-type limited slip can).  And they are less likely to spin a tire than an open diff or loose clutch-type limited slip.  They do have their shortcomings, and for specialized applications they might not be the best choice.  But in general they are REALLY good.

If I'm not mistaken Wilson is running a TrueTrac.


Edited by Nothing Special - 25 June 2022 at 8:27pm
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