What’s up with Ford limited slip rear end? I have one wheel on ice, and that’s the wheel that spins. I thought limited slip was suppose to but the power to the wheel with the most traction. I guess I don’t know why I paid extra for the so called limited slip. Has anyone else noticed this?

 

What you have is a limited slip differential, not a true locker. If it was a true locker then as soon as one wheel started to spin the entire set up would "lock" and both wheels would spin as one. It is my understanding of the limited slip that when one wheel starts to spin the other is given some extra traction, but if you spin up the wheels too fast you just blow right through the assistance offered.

I don't think it's all that much, particularly in your "ice" situation, but I think it does help sometimes.

Hope that helps.

 

That is when you put it in Fx4 and have no worries . . .

 

Sounds like one of my first posts to FTE I couldn't get up my cement driveway if one side was wet, granted it was a bit steep. Took the truck to the selling dealer and they said it was working as expected and the LS "was only there to help get moving while towing" whatever that means. Bottom line is the LS is worthless compared to the ones offered in Jeeps (wife has a Wangler) or my old Vette. A good LS will get the car moving even with no traction on one wheel.

If you don't have 4wd then there are 2 solutions, some have recomended changing the fluid and slowly adding friction modifier 'till the chattering while turning stops. I think 4oz was where most folks said the rear end worked best. Some synthetic lubes don't need any modifier and came highly recomended. Also for quite a few more $$ there are aftermarket LS uints available. I'm now up in snow/ice teritory away from the killer driveway so I just flip the switch and hope the hubs cooperate.

 

How do you know if you have a LS by looking at the tag on the rear diff? I looked this past weekend, and it seems like some of the letters/numbers are smashed under one of the diff bolts, but if I remember correctly, I believe the parts that I could read said something like "L73" or "73L", and I am supposed to have a 3.73 LS on my 2007. Do any of those codes ring a bell? Thanks!

 

Yes, those are the codes for a limited slip Diff on 3.73. You will see this in the tech folder at well (or it was there at one time)

 

I noticed mine was a POS last week when we got a big dump of snow. I will be taking mine back for warranty. Methinks the factory put too much LS additive in the pumkin. If you search other threads, some advicate a procedure to change the fluid that limits the amount of additive you add and top up as required (as per post #4). I had 2 wheels in deep snow and just let the clutch out in Low and the one tire sat static until I hit the throttle. Pathetic! A LS should work better than that, my 75 camaro will turn em both on dry pavement no prob, a new truck with 8000 low stress km shouldnt have problems regarless of surface.

 

Unlimited slip would have been a better name. It's a poor excuse for a posi, but a fitting match for the A/T M&S joke Continental tires. Ford cut too many corners.

 

Limited Slips are driver friendly in icey situations. A true locker will get rear sliding sideways in the ice. The wheels will lock and spin and your rear will crab side ways in certain situations. Thats dangerous when you are going 10 to 20 mph on ice. A trick used by offroaders is to use the brakes and the throttle to help the LS engage when trying to crawl out of a slipery situation.

 

i have a fx4, and i was told to hit the brakes while pulling and all 4 wheels would pull. never happened for me. anyone know how to get all 4 wheels pulling?
thanks
neil

 

A limited slip is not a locking differentail and hitting the bakes is only a way to help the limited slip work better. Applying the brakes as you give it throttle in a crawling situation helps when you are realy stuck.

 

I relize that limited slip is not locking, but it should work better that It does nothing to help traction the way it works now.

 

Mad, I agree completely... The 3.73 LS is weak (at best). I had an 03 6.0 previously and the LS is the one thing I would have changed out to an Eaton if I hadn't traded it.
FWIW The 4.30 LS works great. If fact, I haven't had to use 4X4 on the recent snow days.

 

I just changed the fliud in my diffs last week and actually saw the LS clutch package in the diff. I used Royal Purple synthetic diff oil (75W-90) with no additive and have not experienced any clunking or clicking noises that are normally associated LS diffs. In the past I have slowly applied the emergency brake and this seems to apply enough load to the spinning wheel for the non spinning wheel to start providing traction.

DSMMH

 

DSMMH did changing the fliud help make the thing work like it should?