|
|
|
|
|
|
Registered
Join Date: Sep 2002
Location: Lake Tapps, WA
Posts: 3,070
|
tranny diagnosing question...LSD or not
I recently purchased an SC to use as a daily driver and apparently it was ordered with a Limited slip diff. I have one in my other car and I know the wheels are supposed to spin the same direction with the LSD and the opposite direction with an open diff.
Well on this SC, if you spin one tire manually, the other one does not move at all. Both can be moved independantly but it does not affect the other side. What tranny do I have or is there a problem with the internals of the tranny...everything seems to drive fine though Any help would be much appreciated. Chris
__________________
'67 911S '69 911S, '70 911ST '73 911T Targa Signal Yellow '78 911SC backdate |
||
|
|
|
|
Registered
Join Date: Apr 2001
Location: Linn County, Oregon
Posts: 48,592
|
Either a malfunctioning limited slip or no limited slip...
__________________
"Now, to put a water-cooled engine in the rear and to have a radiator in the front, that's not very intelligent." -Ferry Porsche (PANO, Oct. '73) (I, Paul D. have loved this quote since 1973. It will remain as long as I post here.) |
||
|
|
|
|
Somatic Negative Optimist
|
Chris:
My LSD works as described: Turn one wheel and the other one turns in the same direction. Hope someone knows the answer to your riddle.
__________________
1980 Carrerarized SC with SS 3.2, LSD & Extras. SOLD! 1995 seafoam-green 993 C2, LSD, Sport seats. ![]() Abstract Darwin Ipso Facto: "Life is evolutionary random and has no meaning as evidenced by 7 Billion paranoid talking monkeys with super-inflated egos and matching vanity worshipping illusionary Gods and Saviors ".
|
||
|
|
|
|
Registered
Join Date: May 2002
Location: St Louis
Posts: 4,211
|
Is the car in gear or neutral?
|
||
|
|
|
|
Moderator
|
the disks do wear, causing the break away force to asymptotically approach zero
the dynamic breakaway force will always be greater as the applied torque increases
__________________
Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
||
|
|
|
|
Registered
Join Date: Sep 2002
Location: Lake Tapps, WA
Posts: 3,070
|
so could it be worn discs? Is this part of a general rebuild or does it involve replacement of the LSD? What is the damage on something like that?
Yes, the car was in nuetral.
__________________
'67 911S '69 911S, '70 911ST '73 911T Targa Signal Yellow '78 911SC backdate |
||
|
|
|
|
|
Moderator
|
Quote:
__________________
Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
||
|
|
|
|
Registered
Join Date: Jun 2001
Location: Sweden
Posts: 5,911
|
Even worn discs will turn other tire in same direction if both are off the ground and brake ain't binding.
If other tire doesn't move at all, you have plain vanilla open diff.
__________________
Thank you for your time, |
||
|
|
|
|
Registered
Join Date: Aug 2002
Location: Galivants Ferry, SC
Posts: 10,550
|
Look at the bottom series of numbers on the transaxle casing... look for the "-12" between the type# and serial#. If it's there, it should have LSD.
- Wil
__________________
Wil Ferch 85 Carrera ( gone, but not forgotten ) |
||
|
|
|
|
Moderator
|
Quote:
Discussions w/ several well respected transmission/diff guys confirm it.
__________________
Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
||
|
|
|
|
Registered
Join Date: Sep 2002
Location: Lake Tapps, WA
Posts: 3,070
|
OK, so I looked at the original bill of sale from the factory and the car was supposedly delivered with a LSD tranny. If I have a worn disc, is there any problem with driving it as is? The rest of the tranny works well...little hesitation in some gears and careful downshifts. I guess the question is: am I going to do more harm by not fixing it now?
__________________
'67 911S '69 911S, '70 911ST '73 911T Targa Signal Yellow '78 911SC backdate |
||
|
|
|
|
Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
|
Chris:
Your LSD is simply worn out,.... If you didn't have an LSD, the opposite wheel would turn the other way when you rotate a wheel.Its pretty simple to pull it out the side cover, unbolt the ring gear and have it rebuilt (after you drain the oil, of course). You'll not do any harm by leaving it alone.
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com Last edited by Steve@Rennsport; 01-08-2006 at 02:31 PM.. |
||
|
|
|
|
Registered
|
I would confirm model numbers, the car may have been delievered with an LSD but who knows what happeneds over time with different owners. I would be sure that it truely is an LSD before you go to the hassel of tearing it apart.
__________________
Matthew “Sometimes the questions are complicated and the answers are simple.” |
||
|
|
|
|
Registered
Join Date: Aug 2002
Location: Galivants Ferry, SC
Posts: 10,550
|
PorscheGuy79 makes a good point.... verify that it *should* have LSD first ...( first-things-first, huh?)...
Look for the -12 as stated earlier... - wil
__________________
Wil Ferch 85 Carrera ( gone, but not forgotten ) |
||
|
|
|