40P10touring sedan Posted June 10, 2012 Report Posted June 10, 2012 (edited) Just got my next piece of my 40 ply puzzle, a 67 newport 8 3/4" rear axle with brakes. With some cleaning I find it's the "2" series{742} but while rotating the front input hub and watching the wheel hubs movement I spy a 2.75:1 gearing. Man, I was hoping for alittle over 3 revs!!!...and a posi tag. Think this is too tight a gearing for a big 265 flathead 6 to handle even stock trans let alone with a tremec 5 speed..next find I need to find! Took me 20min to remove the drums...aside from being eons since they were touched I can't imagine why they fought me- I'm on my 3rd coating of marine coat...love that stuff! My lil plymouth LoadRunner...hauls the kids too...all sorts of precious cargo.{engines, kids, rear axles, kids, groceries, a trans someday, maybe the kids again.....} Rusty but trusty..and she's a plymouth too! ...and no, that's my "daughter's" umbrella in there - not mine!...yes, I lay claim to the lil purple mag light, but not that umbrella! Edited June 10, 2012 by 40P10touring sedan Quote
Plymouthy Adams Posted June 10, 2012 Report Posted June 10, 2012 IF this is not a posi..you must lock one axle from turning, are you intending to pull the axles and inspect the carrier unit..at that time I would count the gears and do the division for the true ratio.. these are the available ratio's for the 8 3/4: 2.76, 2.93, 3.23, 3.31, 3.55, 3.73, 3.91, 4.10, 4.56, 4.89, 5.17, 5.57. Quote
Don Coatney Posted June 10, 2012 Report Posted June 10, 2012 My opinion. Anything above 3.55/1 will not work unless you find and use 12-13" tires. Just my opinion. You do the math and make your own decision. Quote
40P10touring sedan Posted June 11, 2012 Author Report Posted June 11, 2012 IF this is not a posi..you must lock one axle from turning, are you intending to pull the axles and inspect the carrier unit..at that time I would count the gears and do the division for the true ratio..these are the available ratio's for the 8 3/4: 2.76, 2.93, 3.23, 3.31, 3.55, 3.73, 3.91, 4.10, 4.56, 4.89, 5.17, 5.57. Actually I plan on pulling the pumpkin out and checking the axle bearings, at which point I should be able to exactly tell what the ratio is since from what I saw on an 8 3/4" dedicated site, the ring gear "should" have the ratio stamped on the side of it. I knew before I picked this axle up that it may entail some added hassles and money, but I really wish to keep this car as "all mopar" as possible. Honestly, the thought never occured to me to lock one side...I'll have to try that version and see if I get anything different. Still plan on taking it apart anyway... Quote
40P10touring sedan Posted June 11, 2012 Author Report Posted June 11, 2012 ...Anything above 3.55/1 will not work unless you find and use 12-13" tires. ...now that would look weird!..not an option here either. Thanks for the input for the optimum gearing. I'm waiting to here back from my brother in law who's got a 67 newport...I want to see what gearing he's got...he mentioned he wanted better mileage and I could only hope he's got a 3.something ratio and we could swap. His 383 4bbl{yeah, he swapped that 4bbl in himself} could handle the 2.76 ratio. Quote
Young Ed Posted June 11, 2012 Report Posted June 11, 2012 My buddy in tx has a 2.93 behind his flathead in his 39 1/2 ton. He claims to have no issues on hills or starting out. Quote
B1B Keven Posted June 12, 2012 Report Posted June 12, 2012 The gear ratio will be stamped on the ring gear. I'm running 2:76-1 gears in my '49 with 32" tall tires. I can easily keep up with freeway traffic. Quote
Don Coatney Posted June 12, 2012 Report Posted June 12, 2012 You can always change out the gearing. That is what I did on my 8 1/4" differential. Bought a new shim kit complete with bearings and crush sleeve. The bolts securing the ring gear are leftys. I found this out the hard way. Quote
40P10touring sedan Posted June 12, 2012 Author Report Posted June 12, 2012 You can always change out the gearing. That is what I did on my 8 1/4" differential. Bought a new shim kit complete with bearings and crush sleeve. The bolts securing the ring gear are leftys. I found this out the hard way. -"hard way", like I tell my kids, there's 2 ways to learn in life! I have to ask why it is that when it comes to working on cars like we do that it isn't the easy way most of the time! -nice B/W pics...I'm supposed to have a few of my uncle's old '39 plymouth touring sedan coming my way someday. -Gotta ask...how many sleaves to get that nice smear pattern? Quote
james49ply Posted June 14, 2012 Report Posted June 14, 2012 Don, where did you get the yellow lead paint????? I want some, right now I use spray paint and spin the gears before it dries. Quote
TodFitch Posted June 14, 2012 Report Posted June 14, 2012 Actually I plan on pulling the pumpkin out and checking the axle bearings, at which point I should be able to exactly tell what the ratio is since from what I saw on an 8 3/4" dedicated site, the ring gear "should" have the ratio stamped on the side of it.... Is the ratio stamped on the gear for people who can't count and do simple division? Rear end ratio is simply the number of teeth on the ring gear divided by the number of teeth on the pinion gear. Quote
TodFitch Posted June 14, 2012 Report Posted June 14, 2012 Don, where did you get the yellow lead paint????? I want some, right now I use spray paint and spin the gears before it dries. Looks like it came in that same kit, there is a packet of yellow stuff and a brush in the middle of the box in the photo. Quote
cwheel1975 Posted June 14, 2012 Report Posted June 14, 2012 Make sure to grease the wheel bearings. The 8-3/4 has an inner seal so rear axle grease does not lube the wheel bearings on these (they're packed with grease like the front wheel bearings are). I did mine with a needle attachment on a grease gun based on information from various forums. Quote
40P10touring sedan Posted June 14, 2012 Author Report Posted June 14, 2012 Is the ratio stamped on the gear for people who can't count and do simple division? ...are you trying to say something? Quote
Don Coatney Posted June 14, 2012 Report Posted June 14, 2012 Looks like it came in that same kit, there is a packet of yellow stuff and a brush in the middle of the box in the photo. Correct Tod. ...are you trying to say something? I believe he did say something. Quote
40P10touring sedan Posted June 14, 2012 Author Report Posted June 14, 2012 (edited) I believe he did say something. Ok, I believe he didn't have to say it like that then, now did he? Did I offend him or something to warrant that....sheesh! I can do simple division...I try not to do simple %#@* though....Tim already mentioned about the division aspect earlier...what would've been the point of bringing it up again and in such a tone except to flame- we don't need that here, do we? When I buy jeans I just read the tag like most folks...I don't feel the need to pull out a tape measurer to confirm it... Edited June 15, 2012 by 40P10touring sedan I removed the word Quote
fstfish66 Posted June 16, 2012 Report Posted June 16, 2012 if the 8 3/4 has never been opened ,,,there should be a tag under one of the bolts with the gearing stamped on it,, Quote
40P10touring sedan Posted June 16, 2012 Author Report Posted June 16, 2012 if the 8 3/4 has never been opened ,,,there should be a tag under one of the bolts with the gearing stamped on it,, True sir, but sometimes those can get torn off one way or the other...mine doesn't have said tag so either she's been opened up or the tag was lost...my 3 brake line clips on the housing are gone - mostly rusted off...the car it came from was buried in mud for a while according to the guy I bought it from so the tag could've met the same fate. I'm researching the '80-'85 caddy eldo rear parking brake/caliper system for this axle...though it seems odd that the parking brake "must" be used to adjust the piston or the rear brakes will not work due to lack of adjustment. I'd use the parking brake every time so this isn't a bad thing for me...just seems odd the system in question "has" to have the E brake used often. Quote
Frank Elder Posted June 16, 2012 Report Posted June 16, 2012 You need to stop trying to get rears out of c body barges....they rarely have anything othe than a 2 ratio.......b body is your best bet for a 3.55 Quote
Plymouthy Adams Posted June 16, 2012 Report Posted June 16, 2012 look at the wagons...majority are 3.23 Quote
40P10touring sedan Posted June 16, 2012 Author Report Posted June 16, 2012 You need to stop trying to get rears out of c body barges....they rarely have anything othe than a 2 ratio.......b body is your best bet for a 3.55 Wellllllll, after two weeks looking for an 8 3/4 "that" one popped up... Quote
40P10touring sedan Posted June 16, 2012 Author Report Posted June 16, 2012 look at the wagons...majority are 3.23 Just got my windshield and rear window out..heading to dinner and then the cruise night to see if the guys have anything for me....Yum, here we come! {yes, red robin..} Quote
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