I don't know anything about nothing... so save the comment...but I also figured that if I know it,,, everybody does... I got into a situation where I let someone else work on my car.... what a night mare... and it had to do with a chevy rear end.... so here goes.. redundant as it seems.... there are those that don't know this... it's been said through the years...55-64 rears are the same... totally false.... so lets start from the begining... 55 and 56 rears are junk... never waist the time it takes to clean one and install it in any thing...here's why... they have what I call dry bearings and a week center section..5&6 axels have the small bearing, no other axel will work in a 5&6... but 5&6.... next 1957...starts to get better here...first year wet bearings... but,.. problem.... 57 is stand alone.. it has the bigger bearing,,, but...5/6 bearing won't work.... and neither will 58.. 58 is the same diameter ... but 1/8'' thinker... so... 1957 axels only work in 1957 housing...1957 was the first year for the posi....and it works in all the 55-64 housings... but if you put it in a 55 you have to use the 55 axels and cut 1/8'' off them as they are too long.. another cool thing for swap meet hunters is chevy cast a big P on the center section... so the rear is laying out of the car....you ask the guy... what does it fit.... the classic answer... what cha got?.... so, what is it??? the easy way I always tell is the cast numbers... this get you at least what year the pumkin is.... on the right side you will see a cast GM... below it there will be 2 sets of numbers... and if lucky a big P... there is what looks like two flat blade screw heads cast... between them is a letter and 3 numbers... the letter lets say E stands for the 5th month...May.... the second 2 numbers are the day of the month and the last number is the year... so if the last number is a 4... it's a 1964 rear... but heres where it get you into trouble...it could be a 55 the they swapped out the pumkin... so now you bought the rear... wanna get bearings and seals... all the seals are O rings on the bearing... theres no C clips so if its there take the drum off... and remove the 4 bolts and nuts to slide the axel out... thats where you need to know what you are looking at..first glance... only 1 O ring.... that a 5,6, or 7... 58's and up have 2...if you get unlucky and there's only 1 O ring.... now you need to know if it's a small or big one.. either have to measure it, if you can't tell by looking... or take it with you to the parts store to make sure you get the right one... if you wanna do it on line.... look at the measure ment on one or the other...5/6,or 7 and compare.... feel free to add or subtract to my post... enjoy PS... another swap meet tool... if you look at the rear end and it doesn't have a bottom drain plug.... keep walking... 57 was the first year for all the good stuff .. bigger wet bearings, posi. 55/56 little dry bearings and week center, and no drain plug...
HMMMM... mine is a 56 and has been in the car for 64 years. I just replaced the bearings and center section 6 years ago. maybe I should tell it its junk.
The 58-64 bearings that you can get today are junk. Also different bearing companies use either one or two O rings, so that's not a reliable way to tell anything. The bearings are supposed to just have grease in them, but the inner seal usually fails early, so they get gear oil into the bearings, and it leaks through the outer seal, which is not designed to retain oil. If you can find original bracket remains on the housing, that could tell you something about the year of the housing...55-57 used leafs, 58 used a center rear upper bracket, 59-64 used one upper bracket off to the side. And there's something about drain plugs to help tell the early ones apart. The rear was also used in Corvettes 56(?)-62. And a smaller version in early Chevy IIs, which uses smaller everything, although it looks the same, and has 4 lug axles.
Great for lightweght cars and engines without a lot of power. Generally blow up specials if you put a big engine in a 55 Chevy. The ring and pinion will shuck them teeth like an ear of corn. Hence the 57 Pontiac axle swap. Blown up many back in my youth. Even saw Freiburger blown one up at Famoso testing the 56 Chevy.
probley mouse powered and low miles... but like I said... not worth scraping the grease off... but if you ever sell it you can say it's a nine inch like every one else... I have a 56 in one of my hotrods... will I change it...no... do I know the differace driving it...no... is it staying yes
you should see what happens when you launch with a trans brake, built the motor built the trans and was waiting on the rear...Said...I'm gonna run it till it breaks... broke at the start line...
They definitely are the weak link in a powerful driveline if they are not set up with slapper bars or some form of anti-wheel hop device. They did hold up to 409s. . . . .
My 57 broke an axle in the high school parking lot in 1971, the spiders not long after that. Pretty much closed that chapter when I first started putting together more serious cars. The Olds/Pontiac rearend (3 rib) was the logical replacement, that lesson didn't come out of any of the school books I was (ignoring), my lessons came in the mailbox every month. Sure, for a cruiser they work fine (until they don't), just don't be showing off to the girls in the school parking lot or the local cruise night, you don't want to have that happen.
great post... it's in my first post...57 first year of the draing plug and bigger 3rd member and bearings... 57 and latter are designed to get oil from the center... thats why 58 had 2 seals... cause 57 design started leaking premature...
thats because in 58 they beefed up the center section, ring gear and all the bearings... but, 55&6's.... lets just say they were real light duty...
Just like any rearend swap, use the one that meets your needs. The 55-64 Chevy car are fine behind a mild performance small block. Street tires (lack of serious traction) helps rearends live, including the 55-64 Chevy car. If you want to put more than 400 hp to it, sidestep the clutch, or slicks, the natural expected result is a broken rearend. Just as a Ford 8-inch has about the same strength limits as 55-64 Chevy car. If you want bigger stronger Ford rearend use the 9-inch. For the GM side, use a later 8.5 10-bolt or the 12-bolt. The earlier 8.2 10-bolt are a little stronger than the 55-64, but the 8.5 is better. Just coincidental, the 55-64 has a 8.2 inch ring gear. I've run the 56 and 57 rearends swapped in cars and not had problems. With both being non-posi. One 3.08 and one 3.70 geared. If you have a 49-54 Chevy car, the 55-57 rear is a great bolt-in swap for open drive.
Not mine either, I broke 2 with a hot 327 4speed. 1-3.36 and 1-3.70. It depends on how violent your shifts are
i ran the numbers on my center it’s a 1960 center. 57 housing with drain plug. it’s a posi we just rebuilt ,411 gears. not sure i’m gonna like them with a 4 speed two ring
Heard a swap meet guy say adding drain plugs, makes them sell faster. Easier maintenance for owner, maybe he was not being 100% honest.
Hello, I am not sure you have your facts straight. The center rear axle gear section fits in 56 through 63 with and without Positraction built in place. Just pop out the old third member and put in the whole new unit. THEN SLIDE IN THE STOCK AXLES AND THE NEW GEAR SECTION IS READY TO GO… We had a 58 Chevy Impala with stock 4:11 Positraction gears. That whole 3rd member was a close friend to me. Every week, on a Thursday, I was under the 58 Impala after school to replace the 4:11 Positraction unit with a better 4:56 Positraction whole unit. Axles out, pop out the complete 3rd member and push the stock axles back in place and now, lower E.T. times at the drags is almost guaranteed. Same stock axles and nothing different other than a stock 4:56 Positraction third member in the 58 Impala. Then later on, when the 4:11 Positraction unit was sitting around, it was installed in a 57 Chevy Bel Air Hardtop to match his high performance 4 speed 283 dual quad power. Pop out the stock axles and take out the old 3:55 to put in the new 4:11 Positraction third member with new Positraction oil. Now the stock axles went right back in place and off to the races… Jnaki We drove the 57 and 58 chevy sedans for 1000s of miles out to the desert, Mexico, up into the mountains, the local drags and cruising daily to high school. It was the most reliable set up for all of us. The neat thing was the interchange between any Chevy year from 55 to 58 at the time. Pop out the stock axles and put in the complete 3rd member center section. Very simple for a definite power ratio. Now, when we started our 1940 Willys Coupe build, we found a 1956 Chevy Rear End with a set of 4:11 Positraction Gears. It was only 3 years old and there was little to none, as far as wear on the gears and axles. So, it fit right under our 40 Willys Coupe chassis. New Positraction oil and lube rolled right down the street when we got the original 283 motor with 6 Strombergs running. Everyone has their new Ford 9 inch stories and that was the next step in the later year builds. But, we all had to start some where in the Gas Coupe Classes and daily drivers. This was 1959-63... The Chevy rear end + axles needed almost nothing to get rolling under any chassis and fit most old cars, without any cutting of the housing or axles. Ahhh…the good old days of hot rod/drag racing in So Cal… But, for Doug Cook, anything he had built up was a trophy winner. Starting out as a real street car as we all did. Three legends of drag racing in So Cal history...
Sticker shock on the axles bearings. I just replaced one. Was leaking. As it turns out the bearing was indeed failing. Driver side is still tight and not leaking so I installed the passenger only. 2 bearings equaled 233$. Also be very careful of the bearing you get. My go to bearing supplier( MS Bearing Supply -formally Dixie Bearing of Tupelo ) did not stock it. ( they usually have everything and I mean everything and usually a large amount of USA made /nos /Timkin etc etc. ) Almost every bearing for the RW 307 R I believe was the number had a plastic seal. Not Rubber. Also check the inside to make sure that the ball bearing /cage separator/isn’t plastic also. Yes even new Timkin has this. You either find NOS Timkin /New Process or get lucky like it did. Where did I go? Oriellys. They let me order and send back if I didn’t like it. Came in an old dusty yellow box. Not a mark on it other than the number. BUT it did have rubber seals outside and the cage stuff looked like original. Outside O rings looked very Good. I bought a pair. Locks were included. Bearing was well made. Do I know where it came from. Nope. Not a mark on it /someone suggested the yellow box was a Toyo bearing which is supposed to be decent but I don’t know. Fit well and I’ve put a 100 miles on it and it isn’t leaking yet. Now for the other info that you need to know. Everyone said NAPA. And I too would have thought the same. After all they carry SKF. 175$ each. And even from the pics the outside seal was plastic and the inside cage didn’t look any better. Word is that Timkin bought up at lot of people and now the rebox game is also pretty common with them. Not downing anybody just be aware. If you can get NOS still in box or know if a supplier that has old inventory use it. If not inspect it. This is a factory 57 rear with a center out of I would say 62-64. Factory 3:55 posi. Nice with my Muncie. Other than I like a little deeper first gear. Hope this helps. Don’t assume every brand name both is good /or that every unmarked box is bad. Just make sure and check
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