I recently bought a 64 C10 LWB Fleetside. I drove it home about 30 miles a good bit the first couple days across and around town with absolutely no problem. In tuning the carburetor i started getting a little more comfortable with the throttle i get into it more (3/4 throttle at most) and heard a loud crunch and slamming. My first thought was the transmission. Upon further diagnostics i pull the rear diff cover and this is the product View attachment 2987282 View attachment 2987283 I have not removed the pinion yet i'm waiting on a bearing kit Though i've inspected the ring gear thoroughly and no damage seems to be done. Would y'all suggest i go ahead and replace the ring and pinion? If so would a posi and a smaller ratio be worth the money? (i believe the trans is a Borg-Warner 4 speed with a granny gear) open to any input thanks!
Whether or not you replace the ring and pinion, might depend on what you want to do with the truck. If you want more highway friendly gears, then you could replace them. If it's a work truck you just putt around town with, and occasionally haul some wieght with, then the gears you have would probably be ok. I'd pull out the pinion and see if there are cracks at the base of the teeth, near the bearing. if they are cracked, they might eventually break off, which is not good. Also if you're looking to change ratio, vans from the 70s use the same center parts, although the housing is longer, and the axles are different. But it looks like you have a coarse spline rear, I thought the coarse splines were only used in 63? I could be wrong. Just beware that if you change ratio, you might need to change out the differential case too, as they had different offsets for different ratios. I think 3.07-3.40 used one, 3.73 up were a different one. and finding coarse spline side gears might be challenging.
Good eye, yes they are coarse splined. I called a differential shop near by and told me no body makes coarse spline gears so i am going to replace the axels. As for the ring and pinion i am looking for something more highway friendly, not planning on hauling anything. I think but am not sure the current ratio is 3.89. The casing has a GM5 on it and did some research and that's where i came up with the ratio so i was expecting to have to replacing the differential case too and thought i would might as well put a posi in it
the casing casting number won't tell you the ratio. you figure that out by counting gear teeth..although the ring gear should be stamped with the teeth numbers, something like 41-11 or similar. Most of them were 3.73 ratio (41 divided by 11)
12 bolt in a C-10? Even the truck 12 bolt came out later I thought (???). Swapped in 12 bolt? I'm not really up on the truck stuff. Anyway, if the R and P are't broken, why replace them? E-Bay a set of side/spider gears for usually around $75.00, and motor on. A granny low Borg Warner? Again, is it really a Muncie SM465 type of trans? You gear remnants look very close to what my 3.70 open, 56 rearend looked like when [pulled the third member out; my side gears were much worse, but the spiders pretty much the same. The R and P were fine, so I got a side/spider gear set used off E-Bay, and reassembled it for the swap meets. The car got a 4.88 Positraction with Yukon axles, and a billet left side bearing cap. When that goes, the 57 Olds goes in. Are't rear ends fun? NOT!!! I am Butch/56sedandelivery.
It's not the original. 4 on the floor i'm pretty sure its a BW i dont have the numbers on hand but i'll get under there tomorrow and post some of the axel and trans
I've been sort of iffy about using used gears. I just figured while i'm in why not put new gears in regards to the side and spider gears
believe me do not buy used gears ( or any gear set) unless you know personally where they came from , I know several people who have gotten mixed and matched stuff from people who think you can use non lapped parts and make it work or make a set .( and they do not ) buy a new set and change the diff and axles to the fine splines as if these broke a axle stub might be next . the money spent will save you headaches later , as for a truck gear set , if its a toy not used like a pick up (carrying stuff in the bed or a trailer ) then a 3:08 set will do you, even for the once in a great while bed load or a car trailer , but if you use it for moving stuff 1/2 of the time and a toy . I would shoot for a 3:40's -3:55 set otherwise the motor is not going to like it and you will have to drive in a gear lower to make up for the lost torque multiplication .
Check the local yards, you might be able to pick up a complete rear assembly for less than it will cost for parts to fix yours. Maybe......
My 2 cents. My parts chaser '78 Ford broke the spider gears, it is 351 with a truck four speed. I replaced the 3:50 gear with a 3:0 and it made a big difference. cruises nice on the highway and if I have a loaded trailer granny is now a useable gear. My experience with a taller gear and truck four speed. Towed the T toMokan with this set up at highway speeds.
The 12 bolt was factory in '64 and up C 10s, even the 6 cylinder trucks. All of them wee course spline that I have been into. If you want a tall gear you rob the center out of a 6 cylinder 3 speed rear they were 3.08s in '65 for sure and I think '64-'66 used the same common factory gear ratios. The reason those spyders took a dump was from wheel spinning. Not just kids and racers spin 'em they also get spun in the field on farm trucks regularly or in the bush on wood trucks. On an open rear the spyders and center pin take a real beating when the tires are spun. The ring and pinion not so much but I would look for chipped teeth aside from what @squirrel has offered. If it were me I would be scouting everyone's junk rears and looking for spyders and side gears with course splines. I could probably find them new if I wanted new but used is good enough for me. I like the course spline axles. One thing to remember just because the local rear end/transmission shop can't find a part doesn't mean that it doesn't exist just that te suppliers that they use don't stock them.
I believe but the deal is you find a rear and pull the entire chuck out of it and set it up in your housing. Dine deal and probably half the cost of new gears. Those old trucks are as plentiful as ticks on a hound, between us me and an old buddy probably own half a dozen or so. They have always been my go to truck for just driving and hauling. The Pusher (see pic) had 3.08 gears, a turbo 400 and lots of small block, I drove it every day for 80K and hauled more crap then a honey wagon. Once we hand an entire A coupe in the bed with some other stuff that I wanted for my own stash. The haul was only about 200 miles though.
you might be confused what rearend it is.... it's the 8.875" truck rear, used from 1963-81 http://www.summitracing.com/search/department/transmission-drivetrain/part-type/ring-and-pinion-gears/brand/yukon-gear-axle/axle-model/gm-8-875-in-truck?N=4294949522+4294945313+402002+4294941460
Sometimes you get lucky. I never got out of second gear. my last pass was 12.03 @ 106 ( or something like that). I got a laugh out of it, we got to talking about that engine and how many bodies its been in and it occurred to me that the heads haven't been off since '97. its an 18 year old mill and still makin' it happen. Guess I got lucky when I screwed that one together.
when i tore mine up it was the spiders too. bad part is i had 2 newer rears laying around but the spiders had different splines and they were also to wide. so i used a trans am rear with a 2.41.1 gear and did well driving back and forth to work. i also have a newer front end too so i have disc and 5 lugs.
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