Rear wheels breaking loose

[RaWarrior]

My '93 f150 XLT ext.cab that I bought recently has a tendency to spin/skid the rear wheels without much effort at all. It is a shortbed (6'box) and the 5.8V8 motor hooked to the E4OD auto. Floor the truck on pavement and one wheel spins until the posi kicks in(3.08 gears BTW), then both wheels spin. For a while(2-3 secs) Put in in 4hi and you'll still get a quick squeal out the rear end. Now I understand that 5.8 has a lot of ***** under the hood, but this truck isn't exactly light either, espically with both tanks totally full there's a good 200lbs of gas over the back wheels and it still does it just as easily. In braking there is a "pulse" on the pedal, the p.o told me the driver's side front disc is warped, I'll probably get around to that this summer sometime. Anyway, it doesn't take much at all to get the rear wheels to skid(never the front). If you brake hard enough where you would brace yourself against the steering wheel, the rear wheels will skid to a stop. This happens enough in driving(around here) that it's getting annoying and wearing out my tires. Today going down a dirt road at only maybe 5mph I applied the brakes about as gently as I could and the rear wheels started sliding (no pulse on pedal, so front discs weren't even grabbing yet). Applied a little more and I got the pedal pulse and the truck stopped off the front discs. The pedal does not feel "spongy" or have excessive play. Also during normal braking sometimes while holding the brake steady all of a sudden I'll get a sudden jerk of deceleration like the vacuum to the booster spiked for a brief moment. My old truck, a '93 std.cab with a 5speed and the 300 and a single spinner rear end would only briefly squeal the rear wheel if you really hammered it and dropped it into first, and I never skidded during braking, ever, and I had really slammed the brakes a few times. My first thought was the rear shocks were bad. From looking they could be the originals, they're pretty rusty and worn. The leaf spring brackets were just replaced. All tires are still good, probably only 30% or so worn and they are off-road tires, pretty deep tread. Any other thoughts/fixes on this? I plan on replacing the shocks since that's a relatively inexpensive thing that should be done anyway. P.S Anyone know where I can get a manual for this truck? It didn't come with one and I'm having a lot of trouble finding one. The dealer has to "special order" one ($$$$) and I can't find a PDF version anywhere, pay or free (though I did find PDF version for '97 through '06 F-150's for free)

[Steve83]

"Positraction" is the name of a limited slip differential used in GM products. Ford used the "Traction-Lok" (aka TracLok). But neither "kicks in" - they're ALWAYS in as much as they're going to be. The torque of the engine against the rear axle will cause one side to always have more traction than the other, and after it revs up & the torque drops off, they'll even out. Also, as the spinning tire heats up, its traction increases (on pavement), so the combination of those effects is why you're feeling it suddenly grab after spinning for a moment. Also, you're undoubtedly letting off the gas pedal slightly after it squeals.

The shocks have no effect on braking or traction (from a stop).

Pull the drums & inspect all the hardware. Click my signature link & look in the Brakes & Hubs album for more info. Be sure to check that all three E-brake cables move freely & release fully. There's also a TSB about cheap brake shoes causing aggressive brake response, so look for that. I might have put it in this thread.

You can dl a free owner's manual PDF from Ford for most '95-up trucks, and there's not much difference between a '93 & a '95 F150.