12 bolt/9" out of old truck in our cars?

I have a 96 lt1, and snapped the rearend. The cheapest rearend I have found is a ford 9" out of a late model ford truck, or a chevy 12 bolt, out of another late model truck. They are so cheap at the salvage yard that I really would like to use them if at all possible. I cannot justify 1800-2000$ for a new rearend when an old one wouldn't break either. So basically, what is all the work involved in fitting it to our car ? Is it something that me and my roomate could do ? We have rebuilt the motor 4 times, and he is a suspension expert (rebuilt his whole suspension and all that). If we cannot do it, and the car doesnt move, then that means I have to buy one that bolts right up correct? I am so pissed at the prices for a new rearend... someone please help!

I know I might have to shorten the axletubes and get new axles, that is fine I want strong axles anyways. I was just wondering how to get the torquearm bracket and the LCA bracket right, thanks for the help.

new axles, gears, fabricating a torque arm mount, fabricating mounts for the LCA's. Brakes and parking cable.

Why would you have to fabricate the mounts for the LCAs? or the brakes and parking cable? If you use the 9" or 12 bolt carrier and then use the axle tubes from the 7.5, you will have everything factory except the torque arm mount.

My friend and I are in the process of building an 8.8 hybrid for my car. We are using the 8.8 from an explorer, it has 2 bolt holes on the right hand side of it that we are going to make an adapter plate bolt to for the torque arm, so we don't have to fugly rig it. We decided to make a jig for the axles to ensure that the length and positioning is correct.

The 12 bolt truck is not as strong as a 12 bolt car rear. Seems backwards, but it is true. Do not waste your time on that one.

is a truck's ford 9" weaker than a car's? I like your idea and that might be the next I will check out, what year explorer did you get that rearend out of? I could build an 8.8" but I'd rather buy something that I could just fab the tq arm mount to and LCA bracket to and launch at 5krpm :)

I am not trying to be a smart ass, but if you need to ask, you probably shouldn't do it. It is a big job requiring considerable fabrication skill. Even if you value your time at $0/h it won't be cheap due to the parts needed. You will need a new differential (posi, spool, whatever you plan to run), gears (ring and pinion) to suit your application, new axles (the correct length with the correct flange for your wheels), bearings, seals, an installation kit, etc. The cost of these parts will vary with what you select, but I'd figure in the $1,000 range. You also need to buy the rear end in the first place. As far as the work involved, as stated, you will need to fab a torque arm mount, mounts for the control arms and springs, brake backing plates, etc. Also, the ABS will not work when you are done without some additional work and parts.

It has been done, but the only way it makes sense to me is if you have a lot more time than money, access to a shop and tools, and a genuine liking for doing this kind of thing. If so, go for it. You will save some $$$ but it won't be a quick and easy project. Still, you will be proud when it's done (if it works).

Rich

I still dont know why you have to fab the mounts for the control arms and springs, unless he is planning on using the axle tubes from the 12 bolt, which doesn't make much sense when the stock ones are the right length and everything is factory. Also, stock axles will work in an 8.8, (not very strong I know, but it will do to get the car running). I plan on having mine done and running for less than $400, with the price for the machined sleeve collars included. Then again, I did get the 8.8, spare 7.5, 4.10s, and differential for free.

I recently got a free 12 bolt rear end. I believe it's out of a truck. It has 3.90 gears and a limited slip in it. I want to get the thing over to my garage and look at it but some guy put locking lug nuts on the wheels (yes the wheels are still on there) and I can't get the things off! I found a locking lug nut removal kit, but it's universal and not garaunteed to work plus it's kinda pricey. If I can ever get the thing apart and over to my house I could get a better idea of what needs to be done to make it work.

I am really goin to come off sounding like an ******* hear but is not intented that way. If you are having trouble with getting locking lugs off without a tool than you dont what to mod a rear to fit. trust me when I say i have seen many people go not get tubes strait and other things. In about 6 month I will be selling my 12 bolt 4 channel since I am going to ladderbar my car and I want a dana 60 anyways. Just keep your foot out of it and save for a rear or get a second job.

I am really goin to come off sounding like an ******* hear but is not intented that way. If you are having trouble with getting locking lugs off without a tool than you dont what to mod a rear to fit.

Perhaps I believe in having the right tool for the job. Maybe I'd rather look until I find something that is intended for taking that locking lug off. I'm not one to go out and ghetto rig something just to get it done. Sure I could drill the locking lug off, of I could take a die grinder out there and flatten the sides of the locking lug until I could use a socket on it. However this is an old rear end that I got for free and I'm not really concerned with putting any more time into it than I have to. I work with a guy that sells custom wheels and chances are he has a key socket that will work for this locking lug nut, I just need to look.

If you weren't aware, locking lug nuts are engineered to make people trying to take them off without the correct tool have difficulty. That's the whole point. It seems like you missed that.

Well, rskrause I have read your posts for a long time, never expected to hear that from you :)
What I was trying to find out I guess was how long do you think the internals of the rearend would last w/ my application, if I were to fab up all the appropriate brackets and such. I had no problem (nor did my roomate) fabbing up our own custom brackets for his LCA's so I do not see how this is much different. I simply was wondering if anyone knows how strong the old internals (posi? or what did they use back then?) will be or if I will have to replace the ring/pinion and all that. There is always a first for everything, and I would rather buy a fixer upper rearend for 150$ for a ford 9" than pay 800 for a used 12 bolt on ebay and get it and find out it doesnt even work. The tq arm bracket will not be the heard part, nor will the brackets, or the aftermarket axles I wanted to buy w/ it anyway. I guess the only thing is making the brackets 100% straight? I have a second daily driver and plenty of time also, so that isnt a factor. The feeling of fabbing up a rearend for 300$ is good to me, when a brand new 12 bolt or 9" would be 2000$ also.

thanks for the replies....
Eddy

Perhaps I believe in having the right tool for the job. Maybe I'd rather look until I find something that is intended for taking that locking lug off. I'm not one to go out and ghetto rig something just to get it done. Sure I could drill the locking lug off, of I could take a die grinder out there and flatten the sides of the locking lug until I could use a socket on it. However this is an old rear end that I got for free and I'm not really concerned with putting any more time into it than I have to. I work with a guy that sells custom wheels and chances are he has a key socket that will work for this locking lug nut, I just need to look.

If you weren't aware, locking lug nuts are engineered to make people trying to take them off without the correct tool have difficulty. That's the whole point. It seems like you missed that.


I bought my car used and had no lock tool with it. I went to the toolbox and used a 18mm 12 point craftsman 1/2 socket and hammered it on and all came off with easy done in less than 5 min. Locks keep the illusion of security.

what I am trying to say is if getting the wheels off has allready became an issue than this is not for you.

By the way I am a heavy truck tech and have 40,000 easy inside the box and dont have all the tools.

When you weld the tubes on most people think when you start welding it stays. Not true because if you are not carfull as it cools it may pull one derection or another. This isnt a job for beginners. Not trying to rant just tying to save you the hardship your heading for .

ahh sorry forgot to mention the welding will be done professionally, but I see what you mean by the welds moving. I will definitly mark where the welds need to be, then bring brackets and rearend to a professional welder.

how hard is it to shorten the axletubes?
will that have to be done professionally as well?

edit*** this was MY post not the guy who cant get the damn tires off the rearend by the way lol... I have the wheels off damnit!

My TA came with locking lugs and no key, I sprayed down the rims to keep spater from sticking and welded a piece of black pipe to the lugs and then used a pipe wrench, 5 mins for each lug

I never understood quite how these things go. Originally pulling a 12 or a 9
out of an old truck and bolting it up to a muscle car was the way to go for backyard mechanics on a budget... now it seems so taboo... and an impossible feat to do... what happend to the people that originated this stuff and new how to do it? They dissapear or something... where did all that lost info go? When ever I'm working on my car and an old timer comes up to me talking about what they used to do I always listen... You can learn some lost methods that work... but damn... what happend to the guys that used to do stuff like this... and how did they do it with half the tools and technology we have now?

They didn't use torque arm suspension in the old days..... leaf spring suspensions made the swap easy. 4-link rear suspensions involved just a little creativity with the simple brackets. The TA makes it difficult. It isn't easy to mount.

Couple that with the fact that in the old days cars and trucks were closer in width.... now you have to face up to the issues of trucks having axles made one width for rear wheel drive applications, but the 4th Gen F-Body having the axle width based on what are really front wheel drive wheel offsets. Throw in the fact that in the old days, cars and trucks all had drum brakes, so the brake problems went away.....

I don't think that anyone has "lost" anything.... the auto manufacturers have simply complicated things in the name of progress and economical parts production.

And no one is saying its "impossible"..... simply suggesting to the person that asked the question that he may have overlooked or underestimated some of the issues. I saw a guy convert a truck 12-bolt to the F-Body configuration. He probably saved about $500. But his first TA mount broke, and after he got all done, he didn't feel the work was worth the savings, and said he would not do it that way again.

Its not impossible, and creative people, with the right knowledge, friends, tools, etc can do the job. Whether is is cost effective is open to debate. The 8.8-inch conversions are extremley economical and seem to be very reliable.

Yeah,I think injuneer is speaking of mine although its a 9" ford.Its definetly not a job for a first timer or even a moderatly skilled fabricator.First off you WILL need to plasma cut your existing brackets off the 7.5 clean the cut and make positivly sure the mounts are the same length when ground so as not to **** the rear end in the car.Very carefull measurements must be taken as well to assure the brackets are welded in precisly the right location to prevent suspension from binding and to retain correct pinion angle.You will have to use the 9" axle tubes as 7.5 axles will not fit in a 9" carrier like they will a 8.8 ford center section.Second major consideration is centering the axles in the housing,ALL of the core housings you will find are not straight after having been in service for 10-20 yrs I have a special rear end jig that sets the housing ends up so they are centered with the centersection.It basically consists of a pair of aluminum pucs that are bolted into the carrier and a long steel rod that slides through the fake bearings/pucs.Your new hosing ends also receive a second pair of pucs and slide onto the steel rod at either end,the rod is threaded at either end and at this time bolts and washers are installed and snugged into place,my axle tubes were 1/4 inch off the centerline and this fixed a potentially disasterous problem.You must also be sure to order the correct housing ends and axle length as this is non refundable if a mistake is made as they are custom.I have over 1200 into mine with new moser axles,housing ends that retain stock discs,spool,gears,and bearings.Also as mentioned I made a very good looking torque arm mount similar in desighn to currie's and it bent and broke during some hard launches, this was hand fabricated by me out of 1/2 inch steel plate and had to be fabbed with the rear in the car so as to get the proper geometry and to retain as much clearence as possible for the d-shaft.I ended up buying Curries mount for 200.00 bucks and thats what brought me to 1200.00. All in all its a beautifull rear-end but could be duplicated using a moser bolt in housing and some good used centersection parts.I would go that route next time ,My weeks worth of time was worth well over 1000.00 to me!!

Bob: thank you very much! Great post from one who has "been there, done that".

Rich

wow, thanks a bunch, that was EXACTLY what I was looking for. I will forward this to my roomate and see what he thinks; but it looks like you have scared me out of it finally. It may be ebay time?

that doesn't look very easy at all. but 1200$ is less than a new one also... so who knows.

thanks again everybody.

If all else fails, I know of a guy with a stock 3.23 rear end complete he wants to sell in FL. Complete Series 3 carrier rear end from a wrecked 94 Z28. Let me know if you want it and I'll see if I can contact with him. I think he is wanting like $175.00 for it.

Well how about this: Since aftermarket shops/companies that sell 12 bolts ready for install into a fourth gen F-body have to source these rear ends somewhere, could you save money by sending them a 12 bolt to prep for you? It's simple business that you want to make money in every phase of what you do, so for a company modifying 12 bolts it would look like this- 1) mark up and make money on a 12 bolt you sourced from somewhere 2) mark up and make money on the parts/supplies used 3) mark up and make money on the labor used. Looks like you could save a little money if you already have a 12 bolt or could pick one up for dirt cheap, has anyone tried this?

ok heres the bottom line guys,first relax and think about what your saying here.the guy asking why you cant just switch axle tubes,well that would work granted the tubes were the same diameter,you said u did it on an 8.8 to another 8.8 which is fine,but going froma gm 7.5 to a 9 inch housing.noooooooooo.to the guy u said the old timers used to bolt up a 9 inch or 12 bolt and go was true back in the days with leaf springs were you could have some lewway as to mounting and thats if u didnt care that the new rear was wider or narrower than the old one,to the guy who said hed rather fabricate one for 300 instead of spend 2000,id like to know where you get paying only 300 for a complete rear including new axles????and i guess if u want to just throw junk in ther eu can do it cheap bt if your going thru all the work of narrowing and welding up new brackets u really want a 120,000 ring and pinion and differential in there????as far as fabricating your own ,if u have no idea or know how to weld forget it..look at all u need,housing ,then it needs to be cut to length,then new axles ,then new brakes cause your old ones wont fit the new rear,then a center section or differential,then fab or buy the brackets and weld them on and hope its straight so your car dont dog track and your tires dont wear out and the pinion angle is correct so you dont chew up u joints....so 2000 for a complete setup isnt too bad,considering the time your going to spend and all the nickel and diming your going to do.........i dont know what your running but theres tons of 11 and 10 second guys running the stock rears and just stuffing them with strong gears,diffs, and axles and thetyre living just fine..that too would cost around 1000

ok, for 150$ I can get the rearend. I can chop where it needs to be chopped after VERY CAREFUL measuring, then get custom axles for about 400-450?$ from moser. I realize it would be more than 300$. It was an exageration. BUT, if I could keep the internals and only replace the axles for oh say 2000 miles (500 break in if need be) and actually go down the track till I spray nitrous it would make the 600$ easily, or would it be just as easy to mod a 10bolt? How many people have run big horsepower out of a 10bolt? I have the stock housing, the posi is just destroyed and didnt want to have to reuse it... but less drivetrain loss is nice..... anyone know what internals will hold what hp in a 10bolt?

http://www.stockcarproducts.com/

Those people have it all to fab anything you could possibly need on a car... you can very well get yourself the rear end of your dreams from them...but it requires skill to fabricate... and thats were you must play your part.