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Hey folks,
Anybody know the type of rearend in a '78 Spider? Was it standard limited slip? How does one tell? If so, is there a specific gear oil to use? Sorry about the questions but, I have had the car 3 weeks and I have not been able to locate an owners manual for it. While on the subject, is there a replacement for Redline I can use until I can find a supplier ? For both the gearbox and diff.

TIA, Mac
 

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Gear oil

A person in our Northern California club who is very experienced with Alfas and owns among several a 69 Spider says that Shell Spirax is the best because it is designed to work well with the moly syncros. I have not gotten any yet as I think you have to buy it from a lubricant wholesaler and perhaps in bulk. But I'm going to give it a try because I have a lot of confidence in this persons opinion.

Good luck, let us know what you think.

Bill
 

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It's a limited slip. Alfa started doing Limited slip differentials in 69? 70? around there.
 

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Gear oil

:( Ok, my trifocals let me down again. I'm not sure if this is the best limited slip rear end oil or not. His specific comments were for the transmission and said you can use it in the diff. also; but he knew I had a 69 and you are correct that l/s diffs. didn't become available until I think the 72 or 73 model. Somewhere I read that it was an option on 73??

Thanks Sniady for catching my flub. Next time I see the xpert I'll quiz about the l/s.

Bill
 

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here is a link i found... will help a little, but it's still unsure. http://www.alfabb.com/bb/forums/showthread.php?s=&threadid=244&highlight=lsd

One way you can probably tell, lift the back wheels, and turn the car on and accelerate it, I'd assume that both wheel's should spin (still not sure about that though:confused: ) if it's a LSD, or I know on my 73 when I turn one wheel right the other goes left, I think that's another way to find out.
 

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Sniady said:
on my 73 when I turn one wheel right the other goes left
I was with you until this statement. Now I'm really cornfused. Sounds painful never the less.

What about the old method of stomping on the gas while sitting on dirt or gravel. Then going back to hopefully admire two 'skid marks'?
 

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...on a limited slip, or maybe it's just mine. When the car is up on four's you spin say the right wheel clockwise and the left will spin's counterclockwise.
 

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Snaidy,

If your diff has never been rebuilt, the chances are the LSD in your diff is no longer limiting slip!
 

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Snaidy,

Sorry, I was just being a smartass.

The LSD unit in the Alfa differential uses plates, similar to clutch discs, to provide the locking action. From the factory, I believe these are set to a 25% locking factor.

After 30 years of use and abuse, it's a good bet these are completely worn out. When worn, the LSD no longer provides any locking action and behaves like an open differential.
 

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sniady,
this could be why you were getting wheel spin in the canyon OR it could be that you were going very fast and are ready to shim the LSD up to make it tighter.
 

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It's almost impossible to determine if the diff is LSD by turning the rear wheels. The alfa design is really nice in that it is NOT engaged until its needed, so there is very little wear. The cross gears run on a very steep ramp so the the diff plates engage only when under differential torque. There are four plates - two are driven buy the ring gear and two drive the axle. The latter are "rough" surfaced to provide friction.

For the stock configuration they are stacked AABB, and get about 25% power transfer. [Note: on early cars all they installed two of each; later cars only had one rough plate and as it is the costliest one]. If you stack them ABAB you get over 60% locking, which is not too nice on ordinary street corners ( lots of slide) - but great handling on a race track.

The best way to identify is by the size and shape of the housing, and the casting marks in it.. There is a thread somewhere that shows pics.

Generally the Duetto and earlier cars had no LSD, the later cars all did. There is a little uncertainty for the 69 - 72 cars.

Robert
 

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That's correct - my 45 yr (130,000 ml) old LSD is still working fine I know because it dug me out of soft sand on a beach in NI - easiest way is to find some grit or sand and accelerate hard - both wheels should spin but if only one does its not working correctly
 

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Discussion Starter #17
Sorry, I guess I should have thanked the respondents for answering my questions when I started this thread OVER 13 YEARS AGO!!!!
Thanks....:wink2:
 
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