BRB-83-911SC

84 Euro S 5-speed: I didn't think my car had it until today. The option code sticker does not have 220, so a month ago or so, I replaced the gear oil with Redline NS, and recently started noticing a chatter in the rear end when starting from a standstill and making a turn. Seemed to me to be symptoms of a limited slip rearend with the wrong gear oil (or missing the additive). So I jacked the rear up today, and spun a wheel (car in neutral), and the other wheel turned in the same direction. This, to me indicates I have limited slip, no?

Anyone ever hear of a factory limited slip without the 220 option code indicating that? What about the gearbox number G2807-11E? Does that indicate LSD? It is a 35,000 mile, unmodified car. PO (original owner) did not add it.

So, can I just drain a bit of the Redline and add the friction modifier? What's the best cocktail for an 84 5-speed, LSD, with weak synchros?

PS: this week held out another pleasant surprise - PO told me the AC compressor was shot, so I put off diagnosing to prove him correct until this past week - was planning to follow Wally's troublshooting process to check the freeze and low pressure swithches, and anticipating jumping the compressor to prove it dead. Car running, AC switch on, started tugging on the connectors for the freeze switch to amke way for the mutimeter - and the compressor kicked on! Stepped inside the car, ice cold air! Couldn't beleive it - has been blowing cold now for the past few outings.

Feelin' good about the car!

Lizard928

Your symptoms sound like a LSD to me.

However if you remove the fill plug on the diff cover you can shine a light in and physically see if it has one

your numbering on the bottom says no LSD too.

So if you have one someone added it at some time.

Landseer

Yes.

Jadz928 and I just made the same discovery on an 84 Euro a few weeks ago.

Somebody ran the VIN code for me and it spit back the 220 code as an originally installed item.

Here it is on the right, with an open diffy on the left for comparison.

It had been chattering a bit, maybe from age/wear. Had a purple fluid in it.

I put Mobil1LS + a container of friction modifer in it. , but don't have enough run time or aggressive start data points to recommend it.

Excellent outcome on that A/C. Still drooling over that car you found. Nice.

Dave928S

Chatter on a turn could also indicate damage to the spider gear pinions. If there was damage, any stray bits could also give you lock up of the spider pinion assembly, which would give you both wheels turning in the same direction like an LSD.

Might be worth taking the back cover off to be absolutely sure. LSD or not ... the chatter could be damage and you're best to rule that in or out.

docmirror

Job for a $100 borescope from ebay. You can look to see if there are clutches in there, and the condition(basic), if not and the spiders are screwed up, you can inspect them minutely with a borescope through the filler.

Landseer

Maybe somebody will be kind and run your VIN on PET 7.1 from the info given in your picture.

Search because there is a procedure somewhere for lifting one rear wheel slightly off the ground and rotating it with a torque wrench to determine condition of the LSD clutches.

Hilton

Interesting.. ran the VIN and got:

WP0ZZZ92ZES840849
Year 1984
Type 928
CountryCode C00
EngineCode M28.21
GearboxCode G28.07

Options are:
058 Bumpers with impact absorbers
220 Locking differential
261 Passenger side mirror - electric - plain
327 Radio - Blaupunkt
395 Light metal wheels - forged
406 Front wheel housing protection [1983-1986]
415 Wider rear track
438 Comfort seat right
454 Automatic speed control
462 Sekuriflex windshield
468 Graduated tint windshield, green side glass
474 Sport shock absorbers (Bilsteins)
489 Symbols and insignia in German
490 Hi-Fi sound system
494 2 speakers on back shelf
494 Amplifier system
499 Version for West Germany
650 Sunroof

(I looked up the codes elsewhere - not using PET7, as PET7 doesn't have a very complete list of option code explanations)

So according to the full options list, it does have LSD

Sounds like you also have front wheel-well liners and the full speaker pack (speaker on rear quarter panels too)

Dave928S

You're a whiz on those option codes Hilton

It would seem that not a lot of credibility can be given to the stickers because there seem to be a lot around like this .. I wonder why?

BRB-83-911SC

Hilton - That's awesome. Everything listed seems to concide with my car - wheel well liners, 8 speakers, sekuriflex, etc. Having Limited Slip is surely a pleasant surprise! Thanks for looking it up.

tilac999

I saw Brian's car and had a ride in it last week and if I thought it was perfect before, now I'm even more sure. Amazing car. LSD is a great option.

I went to look at a car for sale over the weekend. The seller said he 'thought' it had LSD but when I jacked up the rear, car in neutral, only one wheel turned, the other did nothing, same on the other side.
I passed.

On a car with ~300HP LSD is a must in my opinion.

Brad

tilac999

Any easy way to get the PET 7.1 but just the 928 section? I'm looking at a few 928s locally (Massachusetts) and I'd love to know what options they have before I buy. I'm looking at 1983-1986 cars only. Thanks.

SQLGuy

Same thing on my car. Option sticker doesn't list 220, but the transmission is a G28/13 2J (2J = LSD).

On the Redline 75W90 NS, that's the same oil I used, and I thought it was recommended for LSDs... is this not the case?

Thanks,
Paul

Hilton

From a post I put on another site:

BRB-83-911SC

Paul - I think the Redline NS (non-slippery) needs a friction modifier added to keep the LSD clutch packs happy. I have been searching the archives, but have yet to come up with a definitive answer as to what to add to the NS and how much. There is much to read on gear oil, and it is taking me a bit of time to parse it all.

What led me to my discovery is that I started noticing a very slight shudder from the rear end when taking off from a stop while turning a sharp corner - like turning left or right from at an intersection. This started shortly after I changed my gear oil to straight up Redline 75W90 NS. I have no idea what was in there previously.

As for my buddy Brad, he is begining his search for a 928 locally in New England, and prefers an S. I am sure he would apprciate any leads. I'll let him start a thread outlining a bit about what he is looking for, etc.

Thanks all for your input regarding my LSD mystery ride! Even though I don't post much, I consume the collective wisdom, humor, opinions, rants, etc. almost daily. What a great group!

Imo000

Unless you race it or always drive on the limit, you will never know or need a limited slip in a near stock 928.



Mine is also missing the 220 on the option sticker and yet still has one.