How To Identify An LSD (Limited Slip Differential) - Page 2

**AR4me** · #16 (**permalink**) 12-03-2007, 03:01 PM

Quote:

Originally Posted by BigSwede

...the diff itself will work just like intended, in gear (engine shut off) - you can't spin one wheel in one direction and have the other one stand still. If you can that differential is in bits and pieces.

junglejustice · #17 (**permalink**) 12-03-2007, 10:44 PM

Quote:

Originally Posted by BigSwede

...in gear (engine shut off) - you can't spin one wheel in one direction and have the other one stand still. If you can that differential is in bits and pieces.

BigSwede · #18 (**permalink**) 12-03-2007, 11:50 PM

Both of you are describing brake drag, commanly found on Transaxle cars...

**Alfar7** · #19 (**permalink**) 12-04-2007, 07:22 AM

Very simple.
Put the car in neurtal, jack up either side (one tire) If the LSD is set up correctly (free) you will be able to turn the tire with some feel of resistance caused by the spider gears turning and the viscous interface on the clutch disk and floater plates.
If you try quick increases in the rotation it should lock up, in either direction.

JJ:
You know YOU really didn`t know did you, and you were supposed to be the great expert!

"Mean Old Bastard"

jazig.k · #20 (**permalink**) 12-23-2007, 10:32 PM

locking up in both directions is the action of a 2way LSD. The ideal LSD for the drifters out there. while mid-drift you can back off and on the throttle and it should stay locked. much better control.
im led to believe all LSD transaxles are 2way's.

findout wether you have a LSD. drift it in the dry lsd's and non's act completly different. drift it on dirt and the difference is huge with a 2way.
burnouts. iv seen LSD's [1way] single spin and kick in to a twin spin later on in the skid or not at all. sometimes just twin spin.

iv watched a friend do the half tarmac and half dirt thing in a holden non lsd. with both wheels on tarmac the right hand side always spins in any non lsd holden. his was the same. but he was parked and thought he'd show off with the right side on the tarmac and left on the dirt . kick the throttle and apply a little brake [automatic] the left just spun on the dirt and he didnt move anywhere. kept it going and when the left hit the road it slowed quickly and changed sides.

gt601 · #21 (**permalink**) 12-24-2007, 07:29 AM

I have always tested them in the same sort of way as Richard. Most of the time you can have the car in the air and spin one wheel as fast and as quickly as you can and it will make the limited slip grab and force the other wheel in the opposite direction with a pretty good bump. Most of the time you will know for sure doing this but not always.

Paul

sfveloce · #22 (**permalink**) 11-18-2008, 10:15 PM

Wow. I just finished reading that thread and am thoroughly confused.... Someone please help. How do I know if my 74 GTV has LSD. I jacked it up, hand turned the rear passenger wheel, and watched as the driver side wheel spun in the opposite direction in direct proportion to the forward spinning of the P/S rear wheel. What's the verdict?

PietereQ · #23 (**permalink**) 11-19-2008, 06:55 AM

Quote:

Originally Posted by sfveloce

I jacked it up, hand turned the rear passenger wheel, and watched as the driver side wheel spun in the opposite direction in direct proportion to the forward spinning of the P/S rear wheel. What's the verdict?

sfveloce · #24 (**permalink**) 11-19-2008, 12:56 PM

Thanks PQ.
S

AR75T_DK · #25 (**permalink**) 11-19-2008, 01:50 PM

I am no expert, but recall having read about this in "The Alfa Romeo DOCH Engine High-Performance Manual" and found it at page 106.

“To be technically exact, the ZF instructions for doing this test are the following: if one wheel is held stationary the other should turn when 1.5 kgm of torque is applied to it. This is valid for standard 25% lockout. If you already have a unit modified for 47% you’re looking for twice that value, about 3kgm. Since LSD plates gradually wear with use (wear meaning 0.01mm increments of plate thickness loss!) these torque test values will drop to the point where the wheel will turn with the slightest push. This does not mean your LSD doesn’t work, just that the engagement is not so direct any more”

Then another 1-1½ pages more about rebuilding the LSD.

/Allan

**Zunige** · #26 (**permalink**) 11-19-2008, 02:38 PM

Quote:

Originally Posted by sfveloce

Wow. I just finished reading that thread and am thoroughly confused.... Someone please help. How do I know if my 74 GTV has LSD. I jacked it up, hand turned the rear passenger wheel, and watched as the driver side wheel spun in the opposite direction in direct proportion to the forward spinning of the P/S rear wheel. What's the verdict?

**Alfar7** · #27 (**permalink**) 11-19-2008, 07:48 PM

On US 2liter Alle cars the Diff is marked with a forwatd pointed casting shaped like a "V" or such at the bottom of the aluminom housings. Very Distinct. The 115 cars are so tagged...