Hello all,

I've been wanting to change the gear in my 71 442. The 4.66 is way to steep of a gear for what I'm using it for and I want to make sure I'm buying the correct kit. I've been looking around and found some for sale. Here is the title of the ad "Genuine Richmond 3.42 Ring and Pinion Gear Set Bearing Kit GM 8.875" 12 Bolt Car"

Is this the correct ring and pinion and bearing kit for my car?

Thank you,

John

 

No, your factory rear should be a GM coporate 8.5" 10 bolt rear end with bolt in axles.

 

Ok, then is this what I'm looking for? GM 8.5" 10 Bolt 3.42 Richmond Excel Ring Pinion Gear Set w/ Master Bearing Kit ??

 

If its the factory rear end for your car it would take the 8.5 corporate as previously shared. I've not come across a 4.66 ratio in an 8.5 corporate rear end. So before you spend the money ordering the parts I'd encourage you to verify what rear end you have. If you could share a couple photos with us we can help. First would be of the inspection cover, that should also show parts of the housing we can use to key it out. And that would be a simple one to photograph without getting under the car. John

 

There is no such thing as 4.66 gears for a corporate 8.5".


I respectfully suggest that you start by making certain which rear end is in your car. It should be a 71-72 style corporate 8.5" with bolt in axles & a 10 bolt cover. 4.66 is a Type O gear for the Olds 12 bolt cover (10 bolt internals) that ended in 1970.


So, which differential are we talking about?

 

So maybe it has a 4.56. It is a 71 corporate 10 bolt. I used the following equation to determine the gear: ((tire radius x RPM)/168)/MPH

 

I trust you used a GPS & not your speedo to determine vehicle speed.


Pull the cover & figure out what you have before you buy anything.


Are you aware that 3.55 gear sets are now available for the 8.5"? You might want to consider that gear set as well as the 3.42s. Personally I like 3.23 gears with a non OD trans.

 

John , Please post a few pictures of the rear differential under your car...Does the cover have 10 bolt on the cover or 12 bolts on the cover?

 

Hello all,

Thank you for the responses, but I am sure it's the original type rear end for the car. It was determined in this thread https://classicoldsmobile.com/forums...-antispin.html that the rear end is actually a 1971-1972 3.08 posi from a Buick Skylark.

So the question remains, will this gear fit the rear end for my car?

Thanks again,

John

 

The rear axle in your 442 might be original. Oldsmobile installed Buick rear axles in some 1971 cars due to shortages. The 3.08 gears are a great cruising gear and still provide good take off with the big block.

From what I have been told, the Lansing and Framingham plants were solely supplied Oldsmobile rear axles for the 1971 model year due. The other plants used Buick or Oldsmobile rear axles depending on supply.

Some Buick Stage 1's also received 71OW transmissions due to supply shortages. Guessing the shortages stemmed from the GM strike that year.

 

AnthonyP - I have not heard of this before. Where can I get more information about these shortages and what parts were used? I have owned my car for a long time and to me the rear end looks like it has never been changed. The only thing that might lead me to believe someone replaced the rear end with a Buick rear end would be that the parking brake cables where not on the car when I bought it back in '89.

I still want to know if this gear will fit the rear end my 71 442 should have came with originally. This is the gear I am looking at.

Thanks

john

 

My apologies, I forgot to list the gear I am looking at purchasing. So if my car has the original rear end or the Buick equivalent would the following gear be what I need?
"GM 8.5" 10 Bolt 3.42 Richmond Excel Ring Pinion Gear Set w/ Master Bearing Kit"

Thank you,

John

 

John I am selling a NEW IN BOX GM 10 bolt 8.5'' 3.08 RICHMOND RING & PINION GEAR SET. WITH MASTER BEARING KIT.

See https://classicoldsmobile.com/forums...-gear-set.html

 

Thanks HighwayStar442, but I would rather go with the 3.42. I'm thinking the 3.08 would be too much of a transition from the 4.56. I really like the way the gear I have now hooks up and I'm afraid the car would just sit and spin with the 3.08.

 

I just the opposite. But I think you have to find out just what you have under your car first.

 

This may help. The second one is my 8.5 10 bolts

 

Why does everyone think I do not know what is under my car? Am I missing something here or what? It is the 10 bolt that the car is supposed to have under it. It just has Buick code designations for the gear. Buick and Olds used the same rear ends in 71. I matched it up with the service manual I have.

I just want to make sure I'm buying the correct gear for the rear end. I do not know a lot about differentials, but I can tell the difference between them and I know what's under my car!

 

Sorry, 4.66 is a drag racing gear spinning the tire faster. 3.23 is a highway gear spinning the tire slower. At the same RPM.

 

Really thanks, the car was a drag car! So far this thread has been no help. I think I can find this information on my own.

Thanks anyway

 

Yes, that sounds like what you need. If you can post a link that would help with confirming it is the correct one.

 

Here is a link to one I found on ebay https://www.ebay.com/itm/GM-8-5-10-B...pZqsw7&vxp=mtr

and another I found on amazon
I also saw this one that says "Truck" https://www.ebay.com/itm/GM-8-875-12...JZkPzQ&vxp=mtr

 

The first two appear correct for an 8.5" 10 bolt rear; the last one is for a Chevy 12 bolt rear.