> -----Original Message----- > From: John [mailto:jfowler@bridge.com] > Sent: Monday, July 31, 2000 1:58 PM > To: 928 > Subject: [928] 84S US AT option code question > > > Was looking at an 84S last Friday and it had an option code of M220 which > according to the DEVEK specs and tech info sheet is a locking differential > - 40%. Is this the same as a limited slip diff or similar? Is this pretty > much a standard option on automatics. Also, this car had option code M158 > that isn't on the list. Is this the Blaupundt radio Reno option that is > listed in later years (87-91)? > TIA > JohnF > From: Jim [mailto:jim@928intl.com] Sent: Monday, July 31, 2000 10:00 PM To: 928 Subject: [928] RE: 84S US AT option code question the 40 % locking diff is a "limited slip" "posi-traction" it will transfer up to 40% of the power from a spinning weel to the other wheel . So if one wheel is on ice and the other on a dry road , the wheel on ice may spin but some of the power will transfer to the wheel with traction and you can drive away . With out a limited slip or locking diff. one wheel could just spin and you go nowhere. Few automatics were equipped with this feature Jim Bailey 928 International jim@928intl.com 79 928 5spd 80 928 5spd 68 911 5spd From: Wally Plumley [wplumley@bellsouth.net] Sent: Friday, August 25, 2000 9:03 AM To: 928 Subject: [928] Re: 928 with traction control? At 08:19 AM 8/25/00 -0400, Ron Brooks wrote: >I called someone yesterday regarding a 90 S4 for sale and the fellow told >me the car had traction control. I asked him if he meant a limited slip >and he said it was definitely traction control. Did the 928 ever have >traction control as an option? If it did, I was previously unaware of >this. To the best of my knowledge, the 928 never had "traction control" , but the '90 and up had a "PSD" rather than a "limited slip" differential. Three different animals. Limited slip differentials use springs and a clutch pack to allow differential action while still furnishing a limited amount of drive power to the wheel with better traction. The PSD uses the ABS sensors, a computer, and an acceleration sensor (under the driver's seat) to decide when to hydraulically lock/unlock the differential. When unlocked, it functions as a standard open differential. When locked, there is no differential action - it is totally locked. The locking cylinder is located on the right side of the differential, and the electrically driven hydraulic (brake fluid) pump/accumulator are located in the left rear fender behind the tire. There is a light on the instrument panel to tell the driver when PSD is engaged. Traction control uses the ABS sensors and a computer to control wheelspin by either cutting back on power or applying one-wheel braking, or both. Wally Plumley 928 Specialists From: Wally Plumley [wplumley@bellsouth.net] Sent: Thursday, April 05, 2001 8:55 AM To: 928 Subject: [928] Re: LSD At 05:45 AM 4/5/01, Dan wrote: >If the case on the transmission does not have the code number for a Limited >Slip Differential, how does one tell if the differential has been upgraded - >short of taking the transmission apart?? Of course if the case is stamped >for LSD it is still possible that a PO swapped the differential. Put one rear wheel on the dirt and one on the pavement and accelerate moderately. OR Jack the rear of the car, put the transmission in neutral. Turn one rear wheel. If both rear wheels turn in the same direction, you have limited slip. If the other rear wheel turns in the opposite direction, you don't. OR Jack one side of the rear of the car, put the transmission in neutral and try to turn the jacked wheel. If it is difficult to turn, you have limited slip. If it turns easily, you don't. Wally Plumley 928 Specialists From: Ruiz Ed [eds928gt@yahoo.com] Sent: Thursday, May 03, 2001 4:05 PM To: Wally Plumley; Marcus Hutchinson; Gerhard Van Zyl; 928@list.928oc.org Subject: Re: [928OC Public] Limited Slip Diffirential Dear Wally: My GT (with the PSD) acts as a car with limited slip even with the engine off. That is, both wheels spin in the same direction when they are off the ground and the shifter in neutral (and the brake off). ===== Merry motoring, ~ Ed ~ Slate Grey Metallic/Magenta 90GT 928OC Founder & Trustee PCA's 928 Advocate