Need a little advice, have a 57 Chevy 3200 with original rearend, 4.11. I noticed a little oil dripping in driveway, went to replace seal and gasket and noticed a lot of slack, so much that seal won’t hold. What is the best path forward, replace front gear housing because I have so much slack, replace entire rearend? If I replace rearend can I go junk yard, ford 9”? Truck is not a hot rod, straight 6 with turbo 350. Not a mechanic, learning as I go.
Pull it apart to see where the slack is, ring and pinion gear? Spider gears? or like in my case it was a junk carrier... ...
No 9" will be a direct bolt in, spring pads, drive shaft mods needed plus you have a 6 lug bolt pattern. Easiest to find a good used stock rear and swap it or swap the center chunk.
Might first tell us where this "slack" is....I can't tell what you are talking about. Does the U joint yoke move in and out, as if the bearings are loose? or what? pics/video are helpful You can replace it with a 9" ford, if you can afford to get one made to fit the truck. They used a different wheel bolt pattern on Fords, the cars used 5 on 4.5", trucks used 5 on 5.5", the chevy truck was 6 on 5.5". I've swapped in rears from later trucks, Chevy used a 12 bolt rear with 6 lug axles, the same width, from 63 to 69. In 70 they got wider, in 71 they went to 5 lug, but the 4x4s stayed 6 lug. But getting a rear you can find, that has the right wheel bolt pattern, can be challenging. First figure out what wheels you want to use, then think about some of the other things you need to know, like how the rear is mounted, etc. It takes a little fabrication work to put the right 2" wide leaf spring perches on to the new rear, in the correct position (width spacing and angle).
Up through a 68 GMC 1/2 ton rear end is pretty close to the same width and they got wider in 69. 60 and up GMC kept leaf springs in the rear while Chevy had coil springs except for special order leaf springs. Allegedly some Colorado rear axles are 61 inches wms to wms on drum brake rear ends that are 6 on 5-1/2. You have to have your best decoder ring on to figure out what is said on this classic parts forum but there is some useful info there and they tell how to figure out gear ratios https://talk.classicparts.com/threads/colorado-rear-end-swap-information-pics-added-1-3-16.22271/ You want right close to 61 inches WMS to WMS though.
The 60s GMC rears were usually Dana 44 or 60. I have a 60 from a 65 GMC heavy half ton (six lug) in my 59 Chevy 3200. It was almost a bolt in...but only because the spring bushings and shackles have some wear, and I had to shim to get the pinion angle close enough to not vibrate. And the driveshaft yoke is a different size (1350 series vs. 1310), and in a different place. Plus the parking brake cables are different, so that takes some work to deal with. And the brake drums have a bit different offset, and have never been available new that I could find. good luck finding one these days, but it's a possibility.
I can take pic tomorrow, the u-joint yoke move side to side, can hear the slack when rearend off the ground
Is the nut on the yoke tight? I've encountered a few where the end of the yoke has been worn away by the bearing spinning, and the nut bottoms on the threads. The solution is replacing the yoke. But you kind of need to take stuff apart to figure out what's going on. Not much new stuff available for these rear ends. I used to have half a dozen of them in my yard, but they got scrapped long ago.
I don't know if you understood what I said. When the yoke gets worn like that, the whole yoke/pinion assembly will be loose in the housing, and there will be play in the pinion bearings, even though the nut is tight. If you want to fix it, we can help, but you'll have to play along, and do some difficult work. The yoke is the same as used on the 55-64 Chevy cars, so they're not that hard to find.
You are correct, I didn’t understand what you were saying. I will look at it this evening, plan on opening it up.
Do you have the shop manual for the truck? If not, this might help... https://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0402.htm Make sure you have a good idea of how it all works, and how it's taken apart and put back together, before you start on it. The rear cover come off first, then the lock bolt that holds in the pin across the spider gears. Once that's out, you can push in the axles and remove the C clips that retain them, and pull the axles out. Probably a good idea to replace the seals at the wheel bearings, too. After removing the axles, and the driveshaft, you can remove the nuts that hold in the front center section, and carefully take it out, it's heavy! To work on the pinion, you have to take out the differential carrier with the ring gear, and doing so will allow you to also mess up the carrier bearing adjustment, so you have to be prepared to be able to get them adjusted again. And removing the pinion yoke nut will let you remove the yoke and pinion, and you can then inspect all the parts, and get scared about how the gears look, so you'll want to be able to figure out how to post pictures of it, so we can look over your shoulder. You'll want to read the manual first, and study the pictures, but this is just a quick introduction into what you might be in for, so you'll be prepared. Lots of guys won't tackle rear end work, because you need to know what you're doing, and there are some tools required that they don't have.
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