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Discussion Starter #1 (Edited)
I'm a bit different four wheeler than most, I'm not into rock crawling, twelve inch lift kits, 54 inch "swampers", etc... In fact, the opposite is true.. I want to keep the stock ride height, 235x75R15 tires (with an aggressive "mud" tread) and "Freeway Gears"..
In Dec 1973, I bought my FJ-40 Landcruiser to use as a "Hunting Vehicle" from Sept to Feb and as a "Daily Driver" the rest of the time. (we get ice storms down here, and a "chained-up" 4x4 is a fairly safe way to get around)
During the first four years and nearly 100K miles of ownership, I did FIVE Valve Jobs.. the same burned #4 Exhaust. In 1978 I "fixed" the problem permanently.. I replaced the Japanese Imitation Chebby sick cylinder engine with a 1967 429cid Cadillac bolted to a beefed-up TH400 (Trans-Go Shift Kit, HD Clutches, Hurst Shifter, etc.), using an Advance Adapter Kit to bolt the entire thing to the T-Case. After that, I drove nearly a quarter million trouble-free miles (I did have to replace the Accelerator Pump's diaphragm in the Holley Spread-bore Carb.. a fifty cent part). That 250K miles on 4.11 gears probably equals a half million miles with stock Caddy rear gears, so the engine started blowing a bit of oil. I also pulled a 6000lb, 23' Travel Trailer all over Texas, during hunting season. Once thru miles and miles of hubcap deep mud with "chained-up Street Tires" on "unimproved roads".. The nearly 400lbs of torque was the only thing that kept us from getting stuck! I also fitted the Caddy's stock 26gal fuel tank on the floor, behind the front seats. Effectively giving me a 400 mile range, instead of the "stock" 150 miles.
All this brings me to the Pirate 4x4 forum. After I recover from my back surgery (just done on Dec 1 2011), my plan is to upgrade to four wheel disks. Since the "standard set-up" uses the GM "Metric" front Calipers (I'm going to use the "big bore" 2.75" pistons) and I'll be fitting the Caddy Eldo, with E-Brake, (two inch) calipers to the rears, I'm thinking of just basically swapping the Toy's front & rear differential assemblies with a set of GM 8.5" Twelve Bolts out of a 4wd pick-up. This will allow me to fit lockers and 2.73 gears. (I know I'll have to "offset" the diffs-- I don't "need" a centered rear), but I WANT to keep the Toy Front Knuckles and Birfield CV Axles, I believe they, along with aftermarket Birfields, are a helluva lot stronger than the GM "u-joint" set-up. The front diff will require Toyota "outers" with the "inner" splines cut to fit the GM 30 Spline spyders.
So, the question of the hour is..... Has anyone done something like this? What all is involved? What are the pitfalls, etc. Yeas, Nays, Rubber Room Time?? Any help appreciated.
Charles.
 

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With enough money anything is possible but not always practical. If you want to run chevy axles but want to retain factory birfields then may I suggest just running an after market shaft like an rcv. I'm sure they probably make a set for the axle you are planning on running and are a birfield/cv style like factory Toyota. I think if you built a 10bolt/yota hybrid it would be an enormous waste of money. Imo
 

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With enough money anything is possible but not always practical. If you want to run chevy axles but want to retain factory birfields then may I suggest just running an after market shaft like an rcv. I'm sure they probably make a set for the axle you are planning on running and are a birfield/cv style like factory Toyota. I think if you built a 10bolt/yota hybrid it would be an enormous waste of money. Imo
yes.


Dana 44 with RCVs, nice stuff.

 

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Discussion Starter #6 (Edited)
With enough money anything is possible but not always practical. If you want to run chevy axles but want to retain factory birfields then may I suggest just running an after market shaft like an rcv. I'm sure they probably make a set for the axle you are planning on running and are a birfield/cv style like factory Toyota. I think if you built a 10bolt/yota hybrid it would be an enormous waste of money. Imo

Slobuild & Ky Scrambled;
The reason behind using a GM Ten Bolt is it is the only carrier (that I have found) that offers 2.73 gears. Otherwise, there is nothing mechanically wrong with my stock Toyota 4.10's.
I just found and checked-out the RCV Axles.. Nearly $1100 for a pair (and that was for Jeep Splines).. Found nothing on cutting custom splines... That seems high for aftermarket Birfields, I've seen OTC sets for $500/pr in general research.
Also checked Dana 44 gear ratios.. 3.07 is the tallest.. If I wanted that "low" of a ratio, I'd just drop-in a set of stock Toyota 3.70's and buy more beer with the money I don't spend ;-}
Lastly, why are you of the opinion that building a GM Ten Bolt to be an "enormous waste of money"? I've seen a lot of expensive build rock crawlers, no one seems to think those are an ""enormous waste of money"? After all, it's all in what application one wants to use the 4wd for, isn't it?
I do appreciate the info and reply, tho.
Charles
 

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Have you considered putting in a overdrive. not sure what your chances are of finding the old stock Landcruiser overdrive are, but there must be one around that would be cheaper and easier than doing an axle swap. Or, maybe someone makes one to go between an SM420/ 465 and the stock cruiser case?
Then you could easily swap in some minitruck disks in the front, GM in the back, and be done for maybe cheaper.

Cheers-
Dustin
 

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Slobuild & Ky Scrambled;
The reason behind using a GM Ten Bolt is it is the only carrier (that I have found) that offers 2.73 gears. Otherwise, there is nothing mechanically wrong with my stock Toyota 4.10's.
I just found and checked-out the RCV Axles.. Nearly $1100 for a pair (and that was for Jeep Splines).. Found nothing on cutting custom splines... That seems high for aftermarket Birfields, I've seen OTC sets for $500/pr in general research.
Also checked Dana 44 gear ratios.. 3.07 is the tallest.. If I wanted that "low" of a ratio, I'd just drop-in a set of stock Toyota 3.70's and buy more beer with the money I don't spend ;-}
Lastly, why are you of the opinion that building a GM Ten Bolt to be an "enormous waste of money"? I've seen a lot of expensive build rock crawlers, no one seems to think those are an ""enormous waste of money"? After all, it's all in what application one wants to use the 4wd for, isn't it?
I do appreciate the info and reply, tho.
Charles
I can't imagine RCV not making shafts for a 10 bolt. I would be very surprised if they didn't. http://www.rcvperformance.com/store/catalog/index.php

I can understand the want and need for the higher gear set thus wanting to go with a 10 bolt. When I said it would be an enormous waste of money I was referring to making a 10bolt with yota outers just to retain the toyota birfields when aftermarket birfields are available for the 10bolt. Yeah RCV's are going to be expensive but so is a lot of the work you are talking about in machine work. Unless you are a pretty handy fabricator or have friends that are then your going to be around the same ballpark as the RCV's but without a lifetime warranty. A 10bolt already has the brakes on it that you would be trying to swap over to the cruiser outers too so that is money saved.
 

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unfortunately i am going to have to agree with the other guys. while it sounds neat and may meet your needs it also sounds totally impractical/overpriced. if you break anything most of it will be custom parts or one off stuff. A birfield axle is good up to a certain point, but even a longfield axle has a breaking point. for your application a u joint axle will be fine. Find and axle that will let you gear the way you want and just do a swap. I cant see you breaking anything with the tire size you are running. And with highway gears it is going to be harder to break

keep in mind you are on an offroad website so we are a little biased toward the over-built. No one "upgrades" to toyota axles, unless they are in a Sami.
 

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Charles they are saying it's an enormous waste because 10 bolt axles are considered junk axles. At least in our world that is very true they are junk.
I am with roczar. I would do an overdrive or different Trans and run 3.73 Ring and pinions in the toyota axles.
This has to be one of the strangest threads on here in awhile. I feel like I am replying to a 20 year old thread.:laughing:
 

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Charles they are saying it's an enormous waste because 10 bolt axles are considered junk axles. At least in our world that is very true they are junk.
I am with roczar. I would do an overdrive or different Trans and run 3.73 Ring and pinions in the toyota axles.
This has to be one of the strangest threads on here in awhile. I feel like I am replying to a 20 year old thread.:laughing:
Wait for my next thread... it will be even stranger:homer:

If you need more over drive than what an OD transmission or aftermarket box(fairy, ranger, etc) offer, you can always run an NP203 flipped around.

I still fail to see why you need something in the 3.00 range for axle ratio though:confused::confused:

My old S10 had the tire size you mention(roughly 29") and it ran fine with ~3.7 gearing and an overdrive transmission. My parents had same car with 4.1 gearing and an overdrive transmission and it was also fine.

Are you trying for some world's fastest FJ40?:confused:
 

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There are Fairey overdrives for Land Cruisers out there. 5 minutes on Google identified this used unit (scroll down page to the Fairy)

http://www.fjparts.com/transfer_case.htm

If you wanted more options, you could build an adapter for a Land Rover Fairey. IIRC there are several old threads on ihmud.com involving Fairey overdrives. Given your background and desires that forum might be a better fit for you.
 

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Why not an NV4500 bolted up to his stock cruiser case?

That engine would have more than enough torque to power through the rather far spread gears and also offers a 25% overdrive which compared to most is a long overdrive. Also offers a granny first gear which would be good for towing like he said he has done (but I do not condone... That's to much weight and size for a 40 even with excellent brakes.) and then you are much cheaper getting out in the end and still get your longer gears and if still wanting more drop in some fine spline 3.70 thirds from a 78+ cruiser and BAM! done.
 

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Discussion Starter #14
Reply to everyone's Comments.

Gentlemen;
Thanks for your replies.. I'll answer each in their order posted, in descending order below..

Rockzar;
Yes, I considered an overdrive unit.. At the time, the only thing available was
an in-line unit that was fitted between T-Case Rear Output and Rear Propshaft.. This required the propshaft to be shortened six inches.. Therein lies the problem
In addition to wanting the overdrive to engage BOTH front and rear drives, the act of fitting the Big Block Caddy, TH400 and Advance Adapter, my rear propshaft had to be shortened to eighteen inches (flange to flange), lobbing-off another six inches for the add-on OD would be "building-in a serious problem" with the rear cross-shafts. The Jeep SM420/465 Manuals will not adapt to the Cadillac Block.

Slobuild;
Thanks for the RCV URL.. In my quick search, I did not find that URL, only a Jeep Vendor offering a limited selection of the RCV Shafts.
On "carving-up my own pumpkins", I am a pretty fair fabricator (I use to design and build GP Roadracers (the "F-1" class of the era) using a wide (and weird) collection of motorcycle parts, then campaigned the bike myself. I built a 350cc Kawasaki F-9 Enduro powered [single cylinder trail bike, top speed, 65mph], on it's maiden run, I twisted-up 55mph from first gear, pulled a 45 degree wheelie from pure torque when shifting into third [at 100mph] and topped-out, down the straight at the last Race at Dallas International Speedway, at 165mph (I was NOT pulling top RPM!!).. the 650's and 750's [baring "factory triples"] were not capable of that speed in 1972.. Point being, I'm pretty damn good at what I do.. my life depended on it!)
On the GM Axle Set, the year range I had been looking at were drum/drum sets. I'll check out the later disk/disk sets and see what they offer.

Spacecwboy;
How are things down in the piney woods??
On being "totally impractical/overpriced", I never let that sway me from what I want to do (and, No! I'm NOT made out of money). I've always been of a mindset that if I build it, I'm responsible if it breaks.. be it a poor job or bad design. We agree, I am not hard on my equipment (as evidenced by putting 250+K miles of the Caddy/TH400 conversion with NO failures of any kind (excepting normal maintenance).
I understand this is an off-road site.. I do use my FJ-40 "off-road".. just not like you guys do. I am, likewise, an "over builder". And I don't even know what a "Sami" is ;-}

RustyNail;
I understand, that in the Rock-Crawling world, GM Ten Bolts are junk.. In the quarter-mile world, where gobs of horsepower are put to the ground in a hurry, 10's, 12's & 14's are considered the stronger gear-sets.. It's all in the application.
3.73 gears, for me, is not an improvement.. In fact, fitting them (or the stock 3.70's) would be a gross waste of time and money as they would NOT reduce the Caddy's "Cruise RPM" down enough to achieve what I want. On the overdrive, rear what I wrote to Roczar.

Lil John;
I've looked into the 700R4 (I think it is).. It addition to having to redo the TH400 conversion I did in 78 (and at a considerably higher cost), the 700R4 requires a "computer" to operate.. This, in my opinion, is "building-in a problem". As noted, I was a heavy line mechanic for 40+ years.. I've seen more cars hauled-in to dealerships, "on the hook" because of "computer issues" than you can shake a stick at.. With "simple" mechanical systems, such as was used in the '67 Caddy, there are few to no "gremlins" that could cause (me) enough of a problem that I couldn't "slap a band-aid on it" and drive it home.
On "needing" sub 3.00 gearing (2.73's to be exact), I just want the 70mph rpm to be in the low 2000 range instead of the 4000+ range (I don't have the exact numbers in front of me, right now). The Caddy Engine cranks-out gobs of low-end torque.. I don't need, nor want to twist the engine tight just to drive on the freeway.
While the "max top-end" of the Caddy (at 5000rpm) with 2.73's would be in the 150mph range, that is NOT my intent (ya ever "fly" a brick??), only to get the "cruise rpm" down so the engine isn't screaming "SHIIIIFT DAMN-IT!!!" all the time ;-}

Medusa;
I'm pretty certain the Fairey Overdrive was fitted between T-Case Rear Output Shaft and Propshaft.. See reply to Roczar.

CruisinFJ60; (You are just up I-35W from me)
There is no way the New Venture NV4500 will bolt-up to the back of the '67 Cadillac engine. Thus the "need" (and desire) for the TH400. Plus,
I do not need or want to build "one-off" set-ups.. Makes repairs time consuming and costly. At the time I did the Caddy/TH400 conversion, any possible replacement part (including major repair parts) were stock OTC items. While a bit more rare now, the parts are still "out there"..
I don't need a "granny first gear".. as it is, with the 4.10's and the TH400's internal gearing, I move about twelve feet (if I wind it up) before the TH shifts into second (of course, it's also pulling the front wheels up off the road at the same time).. Since doing the Caddy/TH400 conversion, there has NEVER been a reason for me to use low range.. Even when I pulled a loaded 18 wheeler up a two inch thick ice glazed hill.

I appreciate ALL the replies. I can see, now, if I do the GM Axle conversion, like I'd like to, I will be, without a doubt, totally on my own.. I had hopped, from both Pirate and IH8Mud, that I would learn of "what's new" since I did my V-8 Conversion thirty-three years ago, when I was "on my own" then, as well. :confused:
Charles.
 

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Here is a link to gear sets for a 10bolt axle(2.73's). So with readily available gear sets, factory disk brakes(exact ones you would swap to the yota outers) and lifetime warranty axles that bolt up with no mods you would still rather build a one off custom axle just to retain a 37 year old birfield? If so then yeah you might be on your own on this one.

http://www.ringpinion.com/b2c/Produ...8.5-273&Brand=Yukon_Gear_Ring_and_Pinion_Sets
 

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The better question is WHY do you want such high gears? You are going to need an insane amount of power to even get the cruiser moving. Why nto stick with a set of 3.55 or 3.73 gears. You will get up to speed rather quickly, and will be driving with a low RPM.

Honestly, you are working against yourself here. Talka bout making things difficult. If you REALLY want to drive on the highway at decent peeds, get a 700R4 and call it a day. Otherwise, go buy a Wrangler.

Dima
 

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Discussion Starter #17
Here is a link to gear sets for a 10bolt axle(2.73's). So with readily available gear sets, factory disk brakes(exact ones you would swap to the yota outers) and lifetime warranty axles that bolt up with no mods you would still rather build a one off custom axle just to retain a 37 year old birfield? If so then yeah you might be on your own on this one.

http://www.ringpinion.com/b2c/Produ...8.5-273&Brand=Yukon_Gear_Ring_and_Pinion_Sets

Slobuild;
Appreciate the link. I have found a number of places that offer OEM gears for the 10, 12, 14 bolts diffs. That has not been the issue.
I don't believe I said I'd "rather build a one-off custom" just to retain the LC's Birfields (I actually stated to CruisinFJ60: "I do not need or want to build "one-off" set-ups..") My original question was asking about finding someone who made the Birfields that would fit the GM Twelve Bolt (not tens-- RustyNail brought up the use of ten bolts) inner splines and the LC Knuckle outers as my thinking, at that time, that was possibly the only way to go.
IF (that's a big "if") a set of GM 4x4 Ft & Rear End units can be "bolted-up"
under the LC, great!! I'm all for "cheap & simple".. However, I do NOT know (and no one has mentioned) if the GM units (out of a K1500 4x4??) are (more or less) a straight bolt-up item, do they have to be narrowed, are the GM "hams" offset correctly for the stock '74 FJ-40 (three-speed) T-Case? etc.
These are the questions for which I was hoping to receive answers..
IF (there's that big "if", again) the GM units need to be narrowed, or if the diff needs to be offset, then serious surgery will be required.. This I understand. And if this is the case, then I would like to keep the LC Knuckles.. IF the RCV Axles replace the GM "u-joint" type axle as well as covering & sealing the open area between axle tube and knuckle, then that would be a strong viable option, in the scheme of things.
I'm just trying to obtain ALL the information that will help me make an informed and educated decision about my intended goals... and I know not where to look!
Charles.
 

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10/12 bolt axles are junk compared to FJ axles.

There are way more after market parts for the Toyota stuff.
(this coming from a guy who favors Chevy/Jeep/Ford stuff over Toyota).

Go with what you know.
Your TH400 had an overdrive. Go with another overdrive & higher gear set in the Toyota axles.

Disc brakes are not that hard of a swap.

If you do go the 10/12 bolt route, you will end up spending 2x-3x the money that you upgrading your current set up.

Go here & read up: www.ih8mud.com

PS-A few months ago I was helping a friend swap in a D60 rear into his 1950s Chevy pick-up. It had something like 1.79s or 2.03 in it.:eek: (we checked it 10xs!).... Problem would be finding a matching D44 for it.
 

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Discussion Starter #19
The better question is WHY do you want such high gears? You are going to need an insane amount of power to even get the cruiser moving. Why nto stick with a set of 3.55 or 3.73 gears. You will get up to speed rather quickly, and will be driving with a low RPM.

Honestly, you are working against yourself here. Talka bout making things difficult. If you REALLY want to drive on the highway at decent peeds, get a 700R4 and call it a day. Otherwise, go buy a Wrangler.

Dima
Dima;
With the '67 429cid Cadillac & TH400, I have plenty of horsepower.. nearly 400 of them.
The reason for the "choice" of gear ratios is simple.... That's what the stock 1967 Cadillac used, and it had no problem in the take-off, cruise (or top-end) department.
Additionally, the '67 Cadillac engine produces nearly 400lbs of torque, and it produces most of it at a lower rpm (a helluva lot lower than a 350 Chebby).
In all the Four Wheeling I've done, I use to use (need) "Low Four" with the stock six cyl engine. After I did the Caddy V-8/TH400 conversion (in '78), I never needed to use "Low Four" again. The Cadillac's bottom-end torque allowed it to, literally, idle up hills that other 4wd's and "purpose-built buggies" required full throttle to get 3/4's the way up. I pushed a number of these guys over those hills..
By changing the LC's gear ratio, I will (considerably) lower the "freeway cruise" engine RPM (like cut it in half!), this "should" improve the fuel mileage (although I have no expectation that it will) and, if a situation comes up that "Four High" isn't gettin' it, I still have Four Low.. Win-Win, no matter how you slice it!
Besides "Jeep" is a four letter word!
Charles.
 

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Ok. Well I guess I got confused. These two quotes lead me to believe you were trying to build a one off custom axle and even seemed to be proving that you could by your talk about building custom motorcycles. But maybe I see where you were just wanting to use a birfield in a chevy axle. If that's the case then as far as I know(someone might correct me) RCV is the only company that makes they. Not a bad thing though as they seem to make good products.


I'm thinking of just basically swapping the Toy's front & rear differential assemblies with a set of GM 8.5" Twelve Bolts out of a 4wd pick-up. This will allow me to fit lockers and 2.73 gears. (I know I'll have to "offset" the diffs-- I don't "need" a centered rear), but I WANT to keep the Toy Front Knuckles and Birfield CV Axles, I believe they, along with aftermarket Birfields, are a helluva lot stronger than the GM "u-joint" set-up. The front diff will require Toyota "outers" with the "inner" splines cut to fit the GM 30 Spline spyders.
Slobuild;
Thanks for the RCV URL.. In my quick search, I did not find that URL, only a Jeep Vendor offering a limited selection of the RCV Shafts.
On "carving-up my own pumpkins", I am a pretty fair fabricator (I use to design and build GP Roadracers (the "F-1" class of the era) using a wide (and weird) collection of motorcycle parts, then campaigned the bike myself. I built a 350cc Kawasaki F-9 Enduro powered [single cylinder trail bike, top speed, 65mph], on it's maiden run, I twisted-up 55mph from first gear, pulled a 45 degree wheelie from pure torque when shifting into third [at 100mph] and topped-out, down the straight at the last Race at Dallas International Speedway, at 165mph (I was NOT pulling top RPM!!).. the 650's and 750's [baring "factory triples"] were not capable of that speed in 1972.. Point being, I'm pretty damn good at what I do.. my life depended on it!)
On the GM Axle Set, the year range I had been looking at were drum/drum sets. I'll check out the later disk/disk sets and see what they offer.
 
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