I was wondering the best way to test my LS diff. I don't think it is working properly...I had a '93 ranger with 33" tires and 80k miles and it would lay rubber with posi, but my 97 f150 with only 32k feels like it isn't right. I was stopped on a hill (on road) and one tire was on a patch of ice and it just spun and the other side hardly pulled at all...I bought a warranty with it, so I would imagine I could get it fixed if I could show for sure that it isn't right...Like another guy on here said....if my door sticker didn't have the H9 for the code, I would swear it was open! Thanks

 

I'm no expert, but from my limited knowledge of LS rears, you'll not get "posi" type traction in all situations. For example, when both tires have the same amount of traction, both tires should spin. Like on wet roads, going straight ahead, or on gravel. that is the easiest way to check to see if the LS is engaging.

But, like in your example, where one tire had MORE traction then the other, power will transfer to the one with the LEAST amount of traction first. (and like going around a "wet" corner and only the inside tire spins) The LS is then "supposed" to "catch up" with the spinning tire by engaging the "clutches" that are in an LS rear. If the clutches are worn, or you don't have the proper type of gear lube (you have to have a special additive for LS gears!) then, they probably won't have a chance to "engage".

Sometimes, if you lightly apply the emergency brake or lightly press the brake pedal itself, you can slow up the speed of the spinning tire, so that the clutches can then engage and give the tire with more traction some power.

I've done this on rigs with "open" rear ends, and was able to get the other tire some power.

I'd say that in your case, the tire was just spinning too fast for the other to engage and by either letting up on the gas or applying the brake would have given the other tire time to engage.

Just my thoughts.........

 

Jeremy,

Drive to a gravel road and lay a patch, both wheels should spin. Stop, in a safe area, on a road with a gravel sholder with one wheel on the road and one in the gravel. Lay a patch. Gauranteed only the wheel in the gravel spins. That is how the Traction-loc works.

Regards

Jean Marc Chartier

 

On the LS that comes from Ford, only part of the power is transfered to the stationary (non-slipping) wheel. With one wheel on ice and one on dry road, the one on ice will spin freely and the one on dry road will slowly pull the truck away. Still better then an open rear. I plan to replace my LS with an aftermarket one when I change gears to 410's...

 

try your rest (one wheel on ice and one on dry pavement) at different throttle positions.

LSD seems to work better at lower speeds.