Do I have a Limited Slip Differential
 

Hi all,

Is there a quick way to tell whether you have a limited slip differential in your car?

The thread at http://www.pelicanparts.com/ultimate/Forum3/HTML/007527.html
mentions a test where you have the car jacked up and spin one wheel and depending on the direction the other spins you can tell (same direction - LSD /other direction - open diff). Is this test valid?

Can one tell from any of the stampings on the tranny?

I do not have a factory Kardex, which I suppose is the fastest way to tell if one came as OE, and I am not in a hurry to tear the gearbox apart (too many other projects) so is there a quick test?

I think when I was removing the bolts to the CV joints on my car this weekend, turning one real wheel did not turn the other. I wonder if I am in for a big surprise like a broken diff...

Thanks,
Charlie

Hi,
If you jack the car up and spin one wheel the Limited slip (LSD) will make the other wheel spin in the same direction. If the other wheel doesn't spin or spins in the opposite direction then you don't have the LSD.

just tried the test (the guy i bought the car from said he thought it had lsd) and confirmed it does. lifted both back wheels and they both spin in same direction.

explains the rather noisy trans??

wheres that snow??

richard:D :D

Actually limited-slip diff. was not a rare option on 911's, judging from for-sale ads over the years and my dealership experience, but it was an option none-the-less. LSD 915's are kind of scarce on the used market, but I managed to find one that is going in my car one of these days. :cool:

speeder

thanks for bursting that bubble!!

richard:D :D :D

Call or write PORSCHE CARS NORTH AMERICA 1-800-PORSCHE and get the birth certificate of your car. All you have to do is be the regisistered owner and give them the serial number and you will receive in the mail a birth certificate of your Porsche describing all of the options, exterior color, interior color and birth date. So now you can toast the birthday of your Porsche, as I do every year, just another reason to have some Jagermiester. Every year my account says it would have been cheaper if I was a heroin junkie instead of being a PORSCHE junkie, but I won't be lying in the gutter dead with an overdose being a PORSCHE junkie. I hit the wall with a friends Porsche at turn four at Willow Springs the other day and that felt alot better than at shot in the arm. DRIVING IN ITS PUREST FORM, OTTO

I found a european 915 circa 84 vintage that came with 40% LSD in Porto Rico. A lot of European trannies were LSD. My brother in law works there and had the guy checked out for me. Paid $ 900.00 for it. Claimed only to have 70K miles on it. Installed the transmission. With the torque curve being tall and flat with the SC 3.0 it is I believe what the car was designed for. Only 4th and 5th are taller when compared to U.S. 49er cars. 5th gear is an option when driving on the freeway when you want to drop the RPMs and just cruise. approx 85 @ 3000 RPM.
1st gear dog may be somewhat worn something he failed to tell me but the transmission is quiet.
I have RUF 10 inch rears with 255/40's and the ride is quiet with the limited slip. You notice the limited slip working on hard cornering accomplanied with acceleration coming out. Very much different from my 75 915 w/o LSD. Antares

hello all,
hopefully i'm not breaking protocol by doing this, but if you have time can you check out my thread about LSD and PSM in the boxster? <just check the "boxster haven" bulletin board>

any input would be most greatly appreciated!

-dhy

Differential ratio?
 

is any way to know what is the differential ratio (i.e 3.15, 3.23, 3.38)