Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Locking Differential question


Recommended Posts

Car in question is a '99 C2. Option sticker indicates:

M220-LOCKING DIFFERENTIAL 40 %

M222-TRACTION CONTROL SYSTEM

M224-AUTOMATIC LIMITED SLIP DIFFERENTIAL

I had it up on a lift and was turning the rear tires, but the other rear tire was turning in the opposite direction. Any US built car I've ever owned with LSD, the wheels would spin in the same direction. Anybody have any experience with this? Is the locking something that is somehow regulated by the PSM?

Thanks

Link to comment
Share on other sites

  • Admin

From the Tech Book...

"...vehicles have a mechanical limited-slip differential and ABD as optional equipment. The limited-slip differential has different locking values under load and under deceleration.

Locking value under load – 25%Locking value under deceleration – 40%

The lower locking value under load significantly improves cornering behavior. The higher locking value under deceleration reduces yaw due to throttle adjustments in bends and therefore has a stabilizing effect on the handling of the vehicle."

Link to comment
Share on other sites

OK, I'm really confused now. I'm looking at Adrian Streather's 996 The Essential Companion and on page 254 he states:

"All 996 models up to and including 2003 with PSM installed as an option were not permitted to be fitted with any other form of rear differential apart from an open one. This is because the mechanical action of the LSD interfered with the operation of the PSM."

Then on page 299 under the discussion of PSM he writes:

"PSM was originally installed as standard on 1999 996 C4...However it was available as an option for the RWD Carerra model range (option M476), but the cost was prohibitive because along with the PSM syatem, came a different engine, e-gas and a new engine mgmt. software version."

I don't have option M476, and I can see a throttle cable under the car and r&r's one on the throttle body when I did the AOS job so I assume I don't have e-gas...

Link to comment
Share on other sites

I discovered what may have been the source of confusion on my end. I was looking at the owners manual that came with the car and other than a printed date of 5/03, I can't tell what year it's for - though clearly not 1999! So I had been looking at the dash diagram and index where both referenced PSM. When I finally got close enough to my dash button, it clearly reads "TC Off".

Thanks.

BTW - do you know where the serial number is located on the transaxle? I found a few cast-in numbers, but nothing that resembles the trans serial number that is listed on the build sheet printout I got from Suncoast.

Link to comment
Share on other sites

Found the answer to my original question when I finally found my trans serial number. Build sheet says car should have trans serial number GA96002011587 and currently installed transaxle is GA96001022944. Looking at this chart in 996 The Essential Companion the LSD unit must have been replaced at some point with an open unit. :eek:

Kind of sucks, but from what I read, the LSD needs rebuilding fairly frequently. I'm not planning on doing much track time and the TC will help out in snow if necessary. Also, the replacement is 11,357 units newer! Still a bit bummed though. :unsure:

post-33470-0-65920400-1373133490.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.