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Not necessarily because it's a car 3rd member. Depends on what you use the truck for and what's inside. Over the years of the 9" they had different bearings. Example of what I'm thinking, the differential bearings. Over the years there were Small,Medium,Slim Line,Large and Extra Large. If it's got medium bearings and you haul a lot or have a built motor that's tough on drivelines then I'd say find another. And vise/versa. If it's got large and you never tow or haul than I'd say no problem. 28 spline or 32 spline depending on how you drive it. ETC.
Edit. Finding another one and rebuilding it with new bearings and the gear ratio of choice ahead of time keeps the truck down and off the road a shorter time. It's prolly got 28 spline axles all right. You might yank one out real fast just to see what you got if you're going to go searching. You can stab it right back and keep the truck on the road until totally ready.
I will most likely keep it sealed up and find another unit. Axles and 3rd member, rebuild it with heavy bearing everywhere because the truck will haul and go offroading so I don't want any weak points. I am all about over build then under build. Plus I have my bike and this truck so it can't have down time. Any project I get into is always done in a weekend to where the truck is drivable and not sitting weeks at a time. Parts information gathering now on my end. i will see what in what I have now when I have everything to do the swap and most likely rebuild it to have a back up. Thank you for the info sir!!!
[QUOTE=MIKES 68 F100;15850474]crossplaincrazy , not sure where in so cal you are but Sun Valley LKQ shows a nice 72 F100 in stock . you can search inventory .
link
You just called out my maine pick a part MIKES 68!!! shhhhhhh that's my secret stash lol. I will be running there this weekend and they always have a large selections of trucks especially Fords!! Thank you for the link and heads up though!! Greatly appreciated!!
Question. can anything be taken off the econoline vans? I noticed they have a 74 and 75?
I work 5 minutes from there , I would have grabbed that myself but home is 52 miles north . haven't driven Pebbles that far yet and her rear leaks like yours .
I work 5 minutes from there , I would have grabbed that myself but home is 52 miles north . haven't driven Pebbles that far yet and her rear leaks like yours .
Originally Posted by MIKES 68 F100
sorry I'll edit it out for ya !
I travel the same amount of miles on way for work everyday except the opposite way and the bike holds the reliable factor as of now for me lol.. Maybe we could meet up for a pick a part fiesta some day
Thank for editing it out for me and keeping it a secret location lol
i asked above after the fact, but do the parts on the 70's Ford vans work as well?
I noticed the hood part. Should I be looking to completely ditch that and find a truck 3rd member? From what I read that you wrote above. Correct me if I am wrong, but if I find a 9 3/8 rear and take the axles I can use a 3rd member from a dent and have 31 spline axles and this would be basically a plug and play for me? Thank you for the help and I will see what I can do to get you that xray vision
I don't know what the factory ratio was in your truck originally or if your warranty plate is the correct one for your truck (if it's still on the door). If the warranty plate is original to the truck, the code under the Axle heading will tell you what ratio it had.
I suspect it probably had something along the lines of a 3.50 or 3.70:1 ratio (maybe even lower) and some previous owner didn't like the engine spinning at around 2800-3200 RPMs out on the highway and swapped in a car 9-inch 3rd member for the higher gear ratio to drop the engine RPMs. It's probably in the 2.75 to 3.00:1 range but there were also really high ratios of 2.50 and 2.47:1 in some of the Ford passenger car 9-inch rears. --then again, the car 3rd member could have been installed with who knows what ratio.
A car 9-inch 3rd member isn't any weaker than a truck 9-inch 3rd member.
IF you could find some 31-spline axles from a '68-'72 F100 with a 9-3/8" rear end, then you could install them in your truck's existing 9-inch rear, IF you also get a 3rd member with a 31-spline differential. This is what I have in my truck.
The other alternative to that would be to get a complete Dentside rear end with 31-spline axles/differential to install under your truck. You would just have to move the leaf spring perches inward by 2" per side.
I don't know what the factory ratio was in your truck originally or if your warranty plate is the correct one for your truck (if it's still on the door). If the warranty plate is original to the truck, the code under the Axle heading will tell you what ratio it had.
I suspect it probably had something along the lines of a 3.50 or 3.70:1 ratio (maybe even lower) and some previous owner didn't like the engine spinning at around 2800-3200 RPMs out on the highway and swapped in a car 9-inch 3rd member for the higher gear ratio to drop the engine RPMs. It's probably in the 2.75 to 3.00:1 range but there were also really high ratios of 2.50 and 2.47:1 in some of the Ford passenger car 9-inch rears. --then again, the car 3rd member could have been installed with who knows what ratio.
A car 9-inch 3rd member isn't any weaker than a truck 9-inch 3rd member.
IF you could find some 31-spline axles from a '68-'72 F100 with a 9-3/8" rear end, then you could install them in your truck's existing 9-inch rear, IF you also get a 3rd member with a 31-spline differential. This is what I have in my truck.
The other alternative to that would be to get a complete Dentside rear end with 31-spline axles/differential to install under your truck. You would just have to move the leaf spring perches inward by 2" per side.
You hit it on the nose ultraranger!! The past owner was the original owner of my truck. He had bought it brand new in 1970 and kept it until he had passed and his wife sold it to me, but I can see where he changed out the rear end because he used the truck for his business hauling cross country. So what ever car he took this rear end from he was looking for long haul highway miles which now explains why my truck has slow pickup, but cruses at low rpm's on the freeway for a three speed going 65mph. The door tags are not the original though. He replaced those off a F250 at some point and they have the donor truck plate on them. So with out the door plate of axle tag is there any other way to find out what my truck had in the rear originally?
Sorry if I am high jacking this thread. I don't mean to. It just opened up my eyes to the rear now and has me asking a million questions
Not necessarily because it's a car 3rd member. Depends on what you use the truck for and what's inside. Over the years of the 9" they had different bearings. Example of what I'm thinking, the differential bearings. Over the years there were Small,Medium,Slim Line,Large and Extra Large. If it's got medium bearings and you haul a lot or have a built motor that's tough on drivelines then I'd say find another. And vise/versa. If it's got large and you never tow or haul than I'd say no problem. 28 spline or 31 spline depending on how you drive it. ETC.
In reference to axle bearings: Axle bearing size isn't a function of cubic inch engine size/torque but rather, it's a function of GVW capacity for the particular vehicle.
For example, all early Mustangs with either an 8-inch rear or a 9-inch rear all used small axle bearings. It didn't matter if it was a low horse power C-code 289 or if it was a rip-snorting Boss 302, Boss 351, Boss 429, 428 CJ/SCJ, etc., they all had small axle bearings, because the axle bearing size was based on the GVW and not on what was under the hood.
The higher performance early Mustangs with 31-spline axles had small bearings with a larger I.D. for the bigger 31-spline axle journal but, the O.D. of the small axle bearing was the same throughout.
--sort of the same with the '68-'72 F100 9-3/8" 31-spline axles, (as I later found out, and with your help on that). I knew they had 31-spline axles but, I didn't (initially) know there were TWO different versions of the 31-spline axles used in the 9-3/8" rear ends. One axle version has a larger 1-5/8" I.D. on the axle bearing and the other axle version has a smaller 1-17/32" I.D. on the bearing but, the the O.D of the axle bearings for both versions is 3-9/64".
.... So without the door plate or axle tag, is there any other way to find out what my truck had in the rear originally?
It will probably be difficult to see but, if you can locate and read the VIN stamp on the top of the right front frame rail, you can get a Marti report from that VIN number. The Marti report will tell you all the details of how your truck would have originally been equipped from the factory.
In reference to axle bearings: Axle bearing size isn't a function of cubic inch engine size/torque but rather, it's a function of GVW capacity for the particular vehicle.
For example, all early Mustangs with either an 8-inch rear or a 9-inch rear all used small axle bearings. It didn't matter if it was a low horse power C-code 289 or if it was a rip-snorting Boss 302, Boss 351, Boss 429, 428 CJ/SCJ, etc., they all had small axle bearings, because the axle bearing size was based on the GVW and not on what was under the hood.
The higher performance early Mustangs with 31-spline axles had small bearings with a larger I.D. for the bigger 31-spline axle journal but, the O.D. of the small axle bearing was the same throughout.
--sort of the same with the '68-'72 F100 9-3/8" 31-spline axles, (as I later found out, and with your help on that). I knew they had 31-spline axles but, I didn't (initially) know there were TWO different versions of the 31-spline axles used in the 9-3/8" rear ends. One axle version has a larger 1-5/8" I.D. on the axle bearing and the other axle version has a smaller 1-17/32" I.D. on the bearing but, the the O.D of the axle bearings for both versions is 3-9/64".
Oh, I agree with you Steve. When I mentioned the axle bearings I was referencing how worn out axle bearings can cause the axle seal to go bad. Just like the pinion seal. I noticed in his pic there is either gear oil or brake fluid from a wheel cylinder running down his tire.
So this tread got me jumping into the rear end because as you can see it has a bad leak!! Ultraranger or any of you knowledgeably gentleman I have a 1970 F100 and the rear has no tag on it. Here is some pictures of it if you can tell anything about what I have. From reading what you wrote above I know I don't have a "N" case and from the outside of my axles I see two circles which I will guess means it 28 spline axles. If you see something that can help out or advice how to fix my leak I greatly appreciate it. Before anyone else tells me yes I noticed that I have a leak on the drum on the passenger side rear that means to me stop everything else that I am doing and do the front disc swap and rebuild the drums before I drive it again. Junkyard here I come this weekend lol
My truck had a leaky driving pinion seal when I bought my truck (actually, judging from the thick layer of oil/dirt accumulation on the underside of my bed at the time, directly above the 3rd member, it had been leaking long before I bought the truck).
I had the shiny fluid present on the inside of my right rear tire the 2nd day of ownership. I don't know if the fluid on your tire is brake fluid or gear oil (?). On my truck, it was brake fluid 'cause the right rear wheel cylinder blew out on me while I was on my way home from work!
Procedure I've posted before on how I've change out leaky pinion seals.
My truck had a leaky driving pinion seal when I bought my truck (actually, judging from the thick layer of oil/dirt accumulation on the underside of my bed at the time, directly above the 3rd member, it had been leaking long before I bought the truck).
I had the shiny fluid present on the inside of my right rear tire the 2nd day of ownership. I don't know if the fluid on your tire is brake fluid or gear oil (?). On my truck, it was brake fluid 'cause the right rear wheel cylinder blew out on me while I was on my way home from work!
Procedure I've posted before on how I've change out leaky pinion seals.
Thank you very much for the in for Ultraranger and the link!!! You really do help me a lot with your knowledge and willingness to share it with me!! You have helped me figure out the best ways to take on projects with out wasting time and money in the wrong places!! Thank you once again!!!
Thank you very much for the info Ultraranger and the link!!! You really do help me a lot with your knowledge and willingness to share it with me!! You have helped me figure out the best ways to take on projects with out wasting time and money in the wrong places!! Thank you once again!!!
Not that I'm an old geezer, yet, but, the internet didn't exist at the time I got into vehicles (with my old '68 Mustang --in the very early 1980s). It wasn't like there were a lot of people in my area that had an old Mustang either so, it wasn't like I was hanging around with friends, where we would hang out at each others shop and wrench on each others vehicles and share our collective knowledge.
I've always been pretty much on my own, in that realm --same with my F100. There aren't a lot of them running around here and I don't personally know anyone that has one.
Today though, the internet does exist. There's a vast amount of information you can get from it to work on an old Mustang, an old Ford truck or, whatever. --most information is good. Some information is completely wrong. You just have to be able to compare information to determine who explained it correctly and who didn't.
I apologize that many of my posts are long but there are generally many details about any given area of these trucks that are riddled with lots of fine details that needs to be known about, in order not to keep running into gotchas that you didn't get the full story on.
I try to be thorough in explaining these key details so that someone has a better picture of what to expect, without running into something they didn't expect or didn't know about ahead of time. It keeps a person from wasting time and their hard-earned dollars.
I'm a Ford enthusiast just like everyone else here and as such, I make my share of mistakes too. I don't know everything there is to know but, by the same token, I don't mind helping by relating what I do know.
12-08-2015, 04:40 PM
