How to tell if car has Limited slip differential? - The Ford Focus Forum

**InFocusTraSTi** · 06-22-2009, 06:35 PM

Hey guys I was wondering how to tell if my car had a limited slip diff installed? I have heard that helical diffs like the torsen feels like an open diff when doing the test spinning the wheels when the front is jacked up.

**SVTBuckeye** · 06-22-2009, 07:59 PM

??Do a burn out, you should have two black streaks.

**B3NN3TT** · 06-22-2009, 10:28 PM

Lay into the throttle in a REALLY hard corner. If the inside front tire lights up, you lose.

**recar** · 06-22-2009, 11:03 PM

Jack up the drive wheels and rotate one side by hand. If the opposite wheel turns in the opposite direction it is a regular diff. If the opposite wheel remains idle or moves in the same direction it is limited slip.

**BadIdea** · 06-23-2009, 07:22 AM

Stick head out window and look for that inside wheel spinning. Duh.

**InFocusTraSTi** · 06-24-2009, 01:51 PM

LOL nice!!

**SVTBuckeye** · 06-24-2009, 03:25 PM

Lol

**venomrogue** · 06-25-2009, 03:04 AM

Quote:

Originally Posted by SVTBuckeye

??Do a burn out, you should have two black streaks.

not true.

ive done burn outs with my stock diff, in a straight line, and lit up both tires.'

sharp turn, floor it, see if inside tire spins...like the others say.

**Fender** · 06-25-2009, 05:32 AM

Quote:

Originally Posted by recar

jack up the drive wheels and rotate one side by hand. If the opposite wheel turns in the opposite direction it is a regular diff. If the opposite wheel remains idle or moves in the same direction it is limited slip.

x2

**B3NN3TT** · 06-25-2009, 10:48 AM

Quote:

Originally Posted by venomrogue

not true.

ive done burn outs with my stock diff, in a straight line, and lit up both tires.'

sharp turn, floor it, see if inside tire spins...like the others say.

Exactly. If the torque split is equal on both sides, an open diff will leave 2 stripes. The only way to know is to create a situation of unequal torque across the diff and see how the car reacts.

I think the earlier suggestion of jacking it up and turning the tire is the easiest, but lighting up the tire in a corner is the most fun.

**cjmartinyzx3** · 06-26-2009, 12:10 AM

Quote:

Originally Posted by recar

Jack up the drive wheels and rotate one side by hand. If the opposite wheel turns in the opposite direction it is a regular diff. If the opposite wheel remains idle or moves in the same direction it is limited slip.

wont work with a torsen/quaife diff. i have the torsen and it will act as a open diff if there is no torque to bias.

either turn wheel and hit the gas hard and see if it spins or take out the passenger axle and look at the diff... if you see a pin going thru the middle its the stock diff.

not the most fun but you will know for sure

**InFocusTraSTi** · 06-29-2009, 10:27 PM

So I had done the simple lift test for the dif before and though it was open. After reading thiis I decided to just do a clutch dump with the steering wheel turned... and guess what... Two lines... The outside wasn't completely smooth... You could tell there was something in the tranny trying to get grip and then kind of sending it back a bit then re-engaging. I also compared to my brothers 2006 Focus ST... Did same thing clutch dump with the steering wheel turned and it was a huge difference... just burning rubber with one wheel like crazy... Dont know that it matters but I had Toyo RA1's in my car when i did this test and my brother had A/S

06-22-2009, 06:35 PM	#1 (permalink)
InFocusTraSTi TEAM Member Join Date: Oct 2007 Posts: 241	How to tell if car has Limited slip differential? Hey guys I was wondering how to tell if my car had a limited slip diff installed? I have heard that helical diffs like the torsen feels like an open diff when doing the test spinning the wheels when the front is jacked up.

06-22-2009, 07:59 PM	#2 (permalink)
SVTBuckeye TEAM Member Join Date: Mar 2003 Location: Pataskala Ohio Posts: 792	Re: How to tell if car has Limited slip differential? ??Do a burn out, you should have two black streaks. __________________ LEM 2007,2008, 2009 NASA Spec Focus racer w/ LCR racing 2002 SVT, Sonic Blue, NO options, vehicle 896 of 4788 Held at the factory Apr-June 02

06-22-2009, 11:03 PM	#4 (permalink)
recar Senior TEAM Member Join Date: Jan 2005 Location: New York Posts: 2,029	Re: How to tell if car has Limited slip differential? Jack up the drive wheels and rotate one side by hand. If the opposite wheel turns in the opposite direction it is a regular diff. If the opposite wheel remains idle or moves in the same direction it is limited slip.

06-23-2009, 07:22 AM	#5 (permalink)
BadIdea Senior TEAM Member Join Date: Nov 2003 Location: Cleveland Posts: 2,415	Re: How to tell if car has Limited slip differential? Stick head out window and look for that inside wheel spinning. Duh. __________________ '02 svt spec focus silver/black PCA National DE Instructor #200503 107

06-24-2009, 01:51 PM	#6 (permalink)
InFocusTraSTi TEAM Member Join Date: Oct 2007 Posts: 241	Re: How to tell if car has Limited slip differential? LOL nice!!

06-24-2009, 03:25 PM	#7 (permalink)
SVTBuckeye TEAM Member Join Date: Mar 2003 Location: Pataskala Ohio Posts: 792	Re: How to tell if car has Limited slip differential? Lol __________________ LEM 2007,2008, 2009 NASA Spec Focus racer w/ LCR racing 2002 SVT, Sonic Blue, NO options, vehicle 896 of 4788 Held at the factory Apr-June 02

06-29-2009, 10:27 PM	#12 (permalink)
InFocusTraSTi TEAM Member Join Date: Oct 2007 Posts: 241	Re: How to tell if car has Limited slip differential? So I had done the simple lift test for the dif before and though it was open. After reading thiis I decided to just do a clutch dump with the steering wheel turned... and guess what... Two lines... The outside wasn't completely smooth... You could tell there was something in the tranny trying to get grip and then kind of sending it back a bit then re-engaging. I also compared to my brothers 2006 Focus ST... Did same thing clutch dump with the steering wheel turned and it was a huge difference... just burning rubber with one wheel like crazy... Dont know that it matters but I had Toyo RA1's in my car when i did this test and my brother had A/S

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