James Bailey

78-82 are early slips....83-89 Later. Porsche lost a big liability lawsuit over a 930 which crashed and the CAUSE was determined to be the "racecar" style limited slip....so in the American spirit of things Porsche dropped them back to only 40% lockup to protect the stupid from themselves....

Crumpler

Thanks James, that's interesting. I was reading last week about how Porsche had raised the stock suspension on US 964's, because "the American's favorite pastime is litigation", lol.

davek9

Did a bit of searching and didn't see it mentioned anywhere.

Question:
Can an LSD from an Auto Trans be added to an Automatic Trans (same year 85/86) without removing the Transmission from the car?

Thanks in advance,

Dave

Kevin in Atlanta

No.

Cosmo Kramer

Can't you just use Greg's method on an auto and swap the LSD from one ring gear to another?

davek9

That's what I was pondering, drop the half shafts and unbolt the Flanges, or isn't there enough room to remove the parts?

Thanks,

Dave

Edit: the reason I'm asking is the SC car I have for sale doesn't have LSD (and it needs it if keeping the SC installed
I have a auto trans w/ LSD that I picked up last year and this would be putting the LSD unit to good use in a great car whether SC or not.

Kevin in Atlanta

I have separated them in the past but I did it on ground. I would think you would have to drop the and unbolt the rear suspension while the trans hangs on the shocks to get at it all. I could be wrong but you are very close at that point dropping the trans with suspension attached. And then you can replace the TT bearings if necessary.

davek9

Yes, I could drop the suspension for more working room and hang trans from Sway Bar.
If I don't have to deal w/ removing the entire Transmission and TT I wouldn't need to deal w/ all the connections and lines and the TT disconnection.

The car that the LSD is going into is in great shape and Trans looks like new,

E Johnson

The real problem here is not weather you can use the LSD from one gearbox in another. You certainly can. You need to continue to use the same r&p, but these a can be swapped.

The real issue is in the setup. Backlash and preload is not terribly difficult, but is made much harder when you do not have the gearbox removed. That said I have seen it done successfully in the past.

Make sure you change out the differential bearings when you do this as your preload will not work out as well with old bearings. In all likelihood though, you are also going to need some shims, which are not as easy to map out with the gearbox still installed. You will also need a bearing removal tool, as you will likely need to check, and adjust, and recheck you preload a couple of times before you get this right.

If you get this wrong, it is likely that you will do damage to the ring and pinion, possibly the LSD, and potentially the entire gearbox.

Take the time and do it right. pull the gearbox out so that you can work on it in a space and angle that will allow you to get the correct measurements. You will also need a way to measure the backlash, so you will certainly need some tools and gauges to do this correctly.

It is not rocket science here, but it does take some knowledge and time.

Just my .02 on this, as I have done several of these in the past and will continue to do them in the future in all likelihood. LOL

Feel free to give me a call if you have questions.

Erik Johnson
(720) 899-6005 phone

byrdman454

Check this old thread. atb tried this and it will not clear the fuel tank. You would need to pull the crossmember and "drop/angle" the transmission a bit for clearance. Don't forget to pull the airbox and engine crossbar support first.

https://rennlist.com/forums/928-foru...ld-thread.html

Here is another thread of mine that has some info.
https://rennlist.com/forums/928-foru...e-in-auto.html

Bill Ball

One other issue I discovered when swapping an 84 LSD into my 89 trans: If you are putting an 83-85 LSD into an 86+ trans (and vice versa), you'll need a different diff cover if you want your spedometer to work. Look here:

https://rennlist.com/forums/928-foru...fferences.html

Kevin in Atlanta

Sometimes there are no shortcuts.

davek9

Yep just asking of it can be done, and yes both transmission are from 32v 85/86.
The donor trans case is not as nice as what's in the car, else I'd just swap the entire box.

Thank you all for the info and advice


Dave