[zeebo]

hi there. just wondering if someone knows a link to a site that identifies and explains the various rear ends and posi units GM cars had from the early 60s to say 2002. looking for info as to what came in what when you ordered the G80 option. also which cars had which rear ends when you ordered say the 455 or the towing packages. im confused as all get out..lol. i have a general idea, but not for what came under what and why. thanks!

[Formulabruce]

I can start this off the top of my head.. EVERY Single Trans AM HAD a "G80" or Limited slip, and this includes ALL generations. ( this is FACT) They used Eaton ( early had coil spring clutch packs and later had "S" clips for pressure and Later auburn styles were used. ( Cone clutch and not rebuildable)
There are many types of housings including a Hotchkiss style, Pontiac Big and small , and then in 1970 they all went Corporate mostly. Thousands of 12 bolts came with NO "G80"
start here ..http://www.chevydiy.com/history-and-...differentials/
This subject as you have asked with a Broad brush is so vast from just 1960 and up with all GM products it could easily take a Book a couple hundred pages.
Chevy , due to lower torque often went from a std ratio of 2.73 down to a 3.o8, where Pontiacs did not in Firebirds ( 1st and second gens) on autos WITH Air conditioning)
Towing packages often meant a TH400 vs a 2 speed or a TH350..In the later years Overdrive light cars will have a 3.42 and Overdrive as stock on a 4th gen V-8 . Hope this helps..

['ol Pinion head]

"EVERY Single Trans AM HAD a "G80" or Limited slip, and this includes ALL generations. ( this is FACT)"
Sorry Bruce, when it comes to 2nd Gens, "ALL"l of them having a factory posi rear from the factor is not a fact! Many, many, many of the '81 301 base 4 bbl TransAms did NOT come from the factory with a #9 S spring posi carrier, they were built with single track rear.

For the good part of 2 decades beginning in the late '80's I pulled the S spring posi carriers out of many different GM cars in the Pick-N-Pulls, crusher yards, country yards. Years ago, before all the front wheel drive junk became the norm, I had a system pulling core parts in the Pick-N-Pulls. Have been underneath literally thousands of late 70's-81 TransAms & Z28's. Z28's were a different deal, the posi rear was optional. Very seldom, ESP with the late 70's-81 350 Auto cars....seldom were they equipped with the G80 posi carrier.

During the mid 90's, also ran across a few original 2.41 geared single track rears under a few '77 low horse TransAm's. This was very odd, in my experience till I stumbled onto the first '77 T/A built this way, by far, finding a #9 posi carrier was GUARANTEED under a base horse '77 T/A. At the first instance, I couldn't believe it, but I did ck the axle tube dating, as well as dated ring gear, & pulled both rear caps to see if the cast shims had later been replaced with a service spacer & thin shim, or a stack of thin shims. Each of these three '77 2.41 rears dated & coded out as 2.41 single tracks that dated the body tag builds of each car. Over 15 years ago, I noted these exact same instances, maybe here on PY. May have been over on T/A Country, quit posting over there long time ago.

As far as identifying all '60's-early '00's GM rears by a picture book or website, that's funny. If someone is looking a specific rear, feel free & ask a question. Agree with Bruce, it would be a thick book...a huge task. My own experience, can quickly spot by sight all the different '64 up A-body & F-body & Nova rears, as well as the easy to spot big car rears. 90's up to 00's big car rears, I dont mess with them.

['ol Pinion head]

"EVERY Single Trans AM HAD a "G80" or Limited slip, and this includes ALL generations. ( this is FACT)"

Sorry Bruce, when it comes to 2nd Gens, All of them havingba factory posi from the factor is not a fact! Many, many, many of the '81 301 base 4 bbl TransAms did NOT come from the factory with a #9 S spring posi carrier, they were built with single track rear. For the good part of 2 decades beginning in the late '80's I pulled the S spring posi carriers out of many different GM cars in the Pick-N-Pulls, crusher yards, country yards. Years ago before all the front wheel drive junk became the norm, I had a system pulling core parts in the Pick-N-Pulls. Have been underneath literally thousands of late 70's-81 TransAms & Z28's. Z28's were a differentvdeal. seldom, ESP the late 70's-81 350 Auto cars, seldom were they equipped with the G80 carrier, posi was optional in the Z28. Also ran across several original 2.41 geared single track rears under a few '77 low horse TransAm's. This was very odd, in my experience till I stumbled onto the first '77 built this way, by far, finding a #9 posi carrier was GUARANTEED under a base horse '77 T/A. At the first instance, I couldn't believe it but I did ck the axle tube dating, as well as dated ring gear, & pulled both rear caps to see if the cast shims had later been replaced with a service spacer & thin shim, or a stack of thin shims. Each of these 3 '77 2.41 rears dated & coded out as 2.41 single tracks that dated the body tag builds of each car. Over 15 years ago, I noted these exact same instances, may be on here. May have been over on T/A Country, quit posting over there long time ago.

As far as identifying all '60's-early '00's GM rears by a picture book or website, that's funny. If someone is looking a specific rear, feel free & ask a question. Agree with Bruce, it would be a thick book...a huge task. My own experience, can quickly spot by sight all the different '64 up A-body & F-body & Nova rears, as well as the easy to spot big car rears. 90's up to 00's big car rears, I dont mess with them.

[Formulabruce]

Ya know, 'ol Pinion head , You are Right again! I should have said Non 301 cars. I too had pulled a few S spring posis but I also saw a few peg legs in a 301 T/A. When I posted my mind was far from the 301 .. Thanks for setting me straight... Also the Infamous "241"'s with no posi...Thats true too. I guess I should say "Most Pontiac Trans am with over 200 HP had a Posi !! Always more to learn I guess. Thanks for your input as always!