Printable View
I have a 57-61 chevy 10 bolt rear. It has 3725899 casting number and BB stamped on one of the axle tubes. I have it in my 23 T Bucket. I want to convert it to disc brakes and change the gear and carrier to a LSD. Can anyone point me in the right direction? I cannot find much info out on it, like is it a 8.5" rear, what spline, etc. Thanks.
Check Jegs, they list both the disc brake conversion and New Posi units. If you have questions call their tech line, of the manufactures tech line. Worst case you might have to pull a rear axle to verify spline count .....but I think the splines were the same from 55-64.
.
It may not be the way you want to go, but these guys put together complete kits that ensure that all the parts work together, and they'll put together what you want, like just a kit for the rear if you call them - Chevrolet Impala Disc Brakes
For the differential, I needed a complete third member, so I called the guys at "Just Rear Ends" - Just Rear End's Complete Custom Crate Rear End, Ford 8 Inch and 9 Inch Third Member, Chevy 12 Bolt, Posi, Housings, Axles, Wilwood Disk Brakes A father/son team who specialize in differentials, and do them right - just not sure they do the older Chevy third members. There's others out there too, like Yukon Gear & Axle, but I like the small, family run shops when I can find them. I'm pretty sure that all of the '57-'64's were 17 spline, 8.4" ring gear.
I really want to try to keep what I have. All the bracket are in place and I really don't have 3K to put into the rear. Just found out the motor is about 4500.00 and with everything else, Im approaching budget quickly.
I have used the weld on brackets from Speedway with good success, until several years ago thats about the only option you had, uses the standard metric calipers that are cheap and reliable and the brackets are universal that fit 3" tubes I believe.
For your differential, look around for a local 4X4 shop that services the off-road crowd. If they truly support the off-roader's then they will be well versed on swapping out ring & pinion, and also dropping in a posi-trac. I'd strongly recommend that you consider something like an Eaton/Detroit Tru-Track spiral gear locker, which is very, very street friendly, locks solid, and is all but bullet proof.
I would like to put a true track in it. The first thing I need is to identify the rear end. I cannot find anything on what size rear(8.2 or 8.5) what spline axles etc. Cannot find anything that goes back that far. It also has the removable carrier( dumps out like a ford 9")
1958-1970 Full size rear Differential Identification you should find what you need here
The '55 to '64 rear gears are 8.4", 17 spline axles, and with what Charlie posted the BB means you've very likely got 3.36 to one gears. Here's Yukon's link to verify - https://www.yukongear.com/diffdetail...fName%3DGM+55P
rspears thats the info I was looking for. Thanks. Now just need to find the carrier I need and maybe change the ring and pinion to 355-373. Oh and also find the rear disc conversion
The tracloc is a carrier
Thats what I meant the trac loc or true loc. Just need to find the carrier I want.
Found a Auburn carrier for it (5420100). Now to take everything apart. Only thing is, I have never done it. Can anyone give and advice? I looked on youtube and couldn't find anything like what I have. everything was 1964 up. With it being a 57-61 and dumps out the front I know its different than the rear dump.
If you have never done it-don't try------take your housing to someone who does it often------ you won't need a carrier--------the new one(trac loc?) will be different than the one you have , but you will need one that fits the range of ratios that your looking to get-------GM was that way while Ford just used different thickness of ring gears-----
Everything from '57 to '64 was the same design. There was no cutoff at '61 with a big design change. Your differential has a third member that drops out the front after the axles are pulled, exactly like the '64 does. Once you get the third member out you'd be well advised to leave any further disassembly to someone who's done it before, and who will be putting the new stuff in. Like Jerry says, you don't need to buy a carrier if you're switching to a trac-loc or tru-trac, or any other kind of posi-trac unit. Those ARE the carrier, so you'll be wasting your time and money on the Auburn.Quote:
Originally Posted by sefrayser
Well I got it apart. It wasn't that hard. I also removed the third member. As far as the auburn I found a deal on a brand new for 325.00. Had to act quick. Its the one mentioned above. I also found a 373 gear thru richmond gear for around 270.00. I assume that 3.70 down means that a 3.73 or 4.11 will work with the carrier. The stock was a open rear and doesn't have anything in it that resembles a carrier....just gears. I figured that for 325.00 I couldn't go wrong. I also wanted to step the gear up from the 3.36.
you don't pay attention to what we're telling you???????and don't assume that because they are close numbers that a 3.70 and a 3.73 will work with the same carrier.
Well I read the thread update after I purchased the carrier. Like I said I had to act quick or loose it. Now that I have it, I need to get ring and pinion. The carrier said it would handle 3.70 and lower. With that said 3.73 is lower than 3.70 or am I wrong? Either way I'm going to call auburn and Richmond gear tomorrow
Depends on whether they mean "....lower in gear ratio" or if they mean "....lower numerically." If I were reading it I would have assumed that the unit worked for anything 3.70 and lower in number, down to the highway gears around or below 3.00 to one. Calling Auburn/Richmond is a good idea. Assuming? The old story is "Assume" makes an Ass of both U and ME.... Not being a smart a$$, just saying that there's times when checking before pushing that "Buy" button is a good thing.Quote:
Originally Posted by sefrayser
It really crazy how this played out. I have been trying to figure out what I was going to do with the rear. After all the advice and information, I was in a local auto parts store this morning (getting oil)and knew the guy behind the counter. He asked how the build was coming and I told him where I was at with it and so on. He said wait a minute and came out with the carrier. Crazy thing is its the same one I was asking on here about. He said they ordered it for another guy and they were sending it back monday. When he said 325.00 and they sell for 480-500 I had to act.
I need to apolize for some of my comments over the trac loc being a carrier--I have reread the whole thread and see that you weren't calling for that-just a limited slip/posi so the auburn seems like what you were referring to in the beginning. good luck with it fitting the ratio you want -----
It's all good. Believe me I'm cool about the whole deal. I've gone back and fourth and changed my mind 100 times. It doesn't help when this is my first endeavor. I have knowledge and can figure things out but when it comes to what I need is where I'm lacking.
I pulled the rear apart. I have a question, may be stupid but here goes. Is the driver side axle supposed to be shorter than the passengers side? Hope so because mine are.
I suppose you could put them back in, and if the c-clips go in, they are right; if you get the short one in the wrong side, you won't be able to see the end to put the clip on. But, yeah, it seems to me that one side is shorter than the other; been a long time since I had one apart.Quote:
Originally Posted by sefrayser
.
The left is generally 28 7/16" while the right is 29 15/16", a difference of 1.5" side to side. Some of the early axles in this run differed by 1/8" between open and posi units.
There were not any clips. It's a drop out style. I know the drivers side is shorter the the passenger. Seems like a little more than 1" but I have not measured