I apologize for any stupid questions in advance,I'm not very strong when it comes to rears.I have 71 GS 350,I know I don't have a posi,but would like one.I read George's site and know what to look for.Do I need to change the whole rear for a posi or can I just change the gear ratio and would I have to change the axles also?Thanks,Tom.
Tom, did you buy that car off of ebay lasy year? I think I delivered it to your house. Jeff sent me some pictures of it. I could not believe it was the same car. That thing looks awesome. Jeff said you put some headers on it. So if you want a posi you need to replace the center section of the rear end. You need to figure out what size it is. Most 70-72 will have an 8.5 inch (the size of the ring gear). That is if no one has switched them. So you can take it apart count the number of splines on the axles (I think 28) and order a new posi unit. I think Auburn sells one that is pretty good. Now is a good time to change the rear end gears if you were thinking about doing that. I bet you have 2.73's in there now. Depending on how much highway driving you want to do you could go anywhere from 3.08 to 3.42 and still be real friendly on the street. I'm sure someone will correct me if I have given you any bad information. Any more questions feel free to ask.
Hey Kelly, yeah it's me. How's life in New Mexico? Sorry to hear about your trailer. Did they ever recover it? Thanks for the compliments, I'm still putting it back together whenever the weather permits, but you don't have that problem anymore huh? Anyway, I wouldn't have to change the anything else?
Tom, That's right. If you buy the correct posi carrier you can use the same axles and even the same ring and pinon if they are the correct series for the carrier (2 series, 3 series, or 4 series). I'm pretty sure that car has a 2.73 which means if you want to use the same ring and pinon you would need to get a 2 series carrier. That may be hard to find. Most if not all of the replacement carriers are 3 or 4 series. If you end up replacing anything in the rear end make to have it set up by a professional.
Kelly will this work? http://cgi.ebay.com/ebaymotors/GM-8...050078469QQcategoryZ33731QQrdZ1QQcmdZViewItem
Tom check the rear end in your car to see if it looks like the one pictured in the auction. You need to check for the ears on the bottom housing (he has them pointed out in the picture). If the rear in your car has these then it should work.
Tom, you can use a posi carrier for 2.73 and up gears. The other carrier is 2.56 and down. Hey Kelly, its me, Tim, formerly of Henderson Driveline. Made your driveshaft years ago. See you went off to a nicer climate. Still rompin that Regal? Ketch ya later.
I'm just going to jump into this thread cause i'm planning on doing the same thing. Put a Posi and GEars.... :beer
Tom, If you take the rear end cover off, it's the big thing in the middle. The ring gear which is shaped like a big ring is bolted to it and the axles go into either side of it. When we talk about a posi carrier we mean that it has some type of a clutch in it that limits how freely the two axles can turn independent of each other. An open carrier has no clutches. So if you have an open rear end and you do a burn out only one tire spins. If you have a posi or limited slip rear end both tires will spin while doing a burnout (if the clutches are in good shape). So if you want both tires to spin, you have to replace the carrier to the posi type. Now if you want to change the gear (how many times the driveshaft turns to one axle revolution) you need to change the ring gear and the pinion (sold in sets).
Question: Is there a place to buy the 3.42gears and correct posi all together? instead of buying everything separate....
Thanks Kelly,I think I got it now.(I also have the ears on the rear.)So if I open up the back I'll probably find the carrier in there with no clutches and possibly 2:73 gears which is an open rear.If I want a posi and say 3:42 gears I would have to change the whole carrier to one with the clutches and proper gears.So like Marvin asked,you can purchase this complete right?How much does something like this go for? Kelly,if I'm not mistaken you pretty much know how my car is set up,what gears would you recommend?I wont be doing much highway driving ,and if I do the gas mileage and highway speed wont matter.Thanks for the help.Tom.
Usually pkg deals are not the best. A large drivetrain supplier will often skimp on quality & supply either poor quality bearings, races,m & seals, or a less than top quality gearset in such a pkg deal. New QUALITY 8.5 gears are best sourced in the following lines: -US Gear-Strange (Cailfornia Gear or Strange direct) -US Gear-Torqueline (Might ck with Jegs, for years they sold this line.) I set up several hundred sets of US Gear- Torqueline 3.42's & 3.73's & no problems with any of them. -Precision (Reider Racing) -Yukon (if Randys Ring & Pinion reps will guarantee they are US Gear) -Beware of no name 8.5 ring & pinions from China. Richmond 8.5's are also a waste of time & some catelogue sellers will only do pkg deals with Richmond 8.5 gears :af: New Eaton 8.5 & 12 bolt posi units have gone up substantially in the last 18 months. Has to do with the price of steel & increased transportation costs. Best retail (one at a time) Eaton posi carrier deals are usually found on e-Bay. Summit is outrageous on their Eaton carriers Jim M (Monzaz) on this board was advertising new BruteStrength 8.5 posi carriers, might ck with him & see if he has sold them all. Good luck, need more info, feel free & e-mail resto_services@yahoo.com :3gears: Roger
One thing to consider is how much rear end noise you want to put up with. I had a set of 3.73 Eaton gears that really "sing" when you're going down the road. I was looking for something rugged, that could lift off the front end without breaking. Maybe you don't need something that heavy duty. From what I understand the original GM gears are the quietest, and if you're just doing this for occasional stop light quick starts or getting through the snow then try to find a set of gears that won't make you go nuts from all the racket. Others may know more than me on this point but I think it's an important consideration to put into the equation if you're going to be happy with the outcome.
I got a set of US gears (3:42) with a new posi unit and mine are quiet in my 72/GS455---although I gotta say---if you do a LOT of hwy cruising 65+ dont get any higher numericallly :af: then 342 (IMHO). In fact(I think) George N recommends 3:08 and he may be RIGHT!!!!! :TU: Pete
