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I recently purchased a 2005 F-150 Lariat off of the dealer's lot. The one thing that it didn't have that I wanted was a limited slip rear end. Is it possible to add limited slip without replacing the whole differential? What is involved? Can it be done with factory parts or do I need to go to aftermarket?
I'd do a search here and elsewhere before spending some serious change on it. Granted, you will get the usual "I wouldn't buy a truck without it" (this response happens with virtually all similar posts) but at BEST it isn't all that in my opinion. I say this having survived a particularly brutal New England winter and not having had even ONE occassion where it may have been useful. (I have 4X4 and did need that and have had the truck a year now). Not having experienced it, I have read where it's a bad idea if you drive on a lot of snow and ice. (MUCH more likely to 360 completely)! I do some offroading but if I were to do so more extremely then I would go with the locker. LSD will just get you stuck a few feet later. OEM is weak. But as I say, do a search before you spend $600-1K just to get it to say nothing of maintenance costs.
I agree with Curve, the first winter I had my 97 f150 (with LS) I did a 180 on the express way going 10 mph. My 00 150 didn't have it and I didn't miss it. My 04 has it and I drive much more careful in the winter (given my past experience). I looked into replacing my 00 rear end (non LS) and the best price I found was $700 and that didn't include a pcm reflash. LS was around $900 from the same shop.
I asked the same question a while back. My 2004 Lariat 4x4 doesn't have the LS and I was worried how it would perform in the winter. There was only a couple of times I had to shift into 4x4 when one back wheel was on ice and the other was not. Most of the time it was going up my own driveway since its a long sloping hill.
I'm a bit concerned about launching my boat this summer, but I will wait to see how that goes before I pass judgement.
LS can aid in traction for certain conditions but it can also be a deterrent when cornering and slick off camber conditions. I agree the stock LS is weak … Also it might be hard to actually find a true locker for these rear ends.
I thought the LS helps wheel spin off the line. Why would you be more apt to do a 180 going 10 mph? What's the point of having a LS if it only makes you slip? I live in a very snowy environment and I am finally ready to purchase. Please help
The reason I was considering LS was because I don't have 4wd. So, in slippery conditions I only have 1 wheel drive. But, since I don't have experience driving a LS truck in slippery conditions I didn't know how it afffected handling.
Still the basic question is: If I decide to go to a LS rear end can I do it by replacing some of the internal parts or do I have to replace the whole rear end?
Thanks for the help.
LS does help off the line by attempting to more equally distribute power. This equalization is not a benefit in slick off camber conditions if both wheels happen to slip, as it sends the slipping wheels down hill and that can be quite a predicament! In these conditions it's nice to have a selectable locker to get through touchy off camber spots. As for cornering ... the fighting of the wheels trying to spin at the same speed can overcome the critical traction point causing that ol rear to come around on ya (e.g. 180). ... Bottom line is; if there is no intention of going off-road it is much safer to run an open diff. Here though, LS can be good for pulling a boat up a slick ramp if not 4x4.
Personally I run a tightly sprung aftermarket LS/Posi and would have put in a selectable locker if a good one was available.
LS can aid in traction for certain conditions but it can also be a deterrent when cornering and slick off camber conditions. I agree the stock LS is weak … Also it might be hard to actually find a true locker for these rear ends.
Too bad they can't get it right like GM did with their Eaton lockers.
My response to those of you who think LS and lockers are dangerous on slippery surfaces: Learn how to drive them. People who spin around are too heavy on the air pedal. That is right, I said air pedal.
Personally I can't stand it when my back end can't get squirrelly when I want it to! It’s just a part of the being in control! That spin the ol one tire thing rubs me wrong! And feels like a lack of control to me.
NOTE: The issue with these drive by wire throttle setups is; that finite control we once had is now gone! Do go out and push the edge in safe conditions until you relearn how to drive on the edge all over again before it is too late! You’ll now need to figure out how your particular computer code reacts in touchy situations. The throttle lag and surge characteristics can put you in a bad situation or worse!
yes, you can swap in a factory LS. My dad bought his 04 XLT with the 3:55 non-LS rear end. He was tired of slipping around everywhere, so he had LS installed at the Ford dealer using Ford parts. He saved money though at the time he did this. Because his truck had the rear axle whine condition, so they had the rear end apart to change the ring and pinion gear set, it was really easy for them to install the LS. In total, the LS cost him around $450 (approx. $390 parts + $60 one-hour labor). I'm not sure what it would have cost him if the rear end wasn't already torn apart. I suggest asking several of your local dealers and see what they would charge you.