Gearing and T-case Advice

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Ok, I Have a 67 fj40 Stock, with the exception of a Chevy 350.. I will Be doing a SOA, Shackle Reversal, Cut and Turn Front Axel.. all to run some 35"s... What do you guys think is best for gearing this beast.. I will be driving it around town, and on the trail i want to be able to take it up anything i encounter..

4.88's in axels with a 3-speed t-case

RockBox??

Marlin Dual T-case??

Marlin 4.7:1 Gear Replacment??

What is the best Cost/Benefit on these setups.. anything elce you guys can think of??

i am open to changing out the Trasmission, maybe even going Automatic..??

Thanks,
Trevor
 
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What a great problem to have... how to spend your disposable income...

It seems to me, six of the key considerations for major drive train modifications are: engine performance (EFI, cooling requirements, torque at low RPM's, etc.), overall fitment (engine position, drive line lengths, etc.), maintainability of components (parts availability) total project cost (there are a lot of "hidden costs" in some upgrades, durabilty for YOUR usage, and gear reduction options...

I read a couple of posts on this site about a V-8 conversion using a 700r4 auto tranny (that's a long one) and the individual had some "short rear drive line issues" I would measure, measure, and measure some more before buying anything...

I have an 1972 FJ40 with a Olds V-8, Th350 auto, Marlin Toybox with 4.7 gear set, and a four speed T-case with 3 speed gears (2.23:1).

In order to make things fit "well" I had to move the motor 2" forward, build new mounts for the radiator, relocate the frame cross member that sits above the T-case and rework all my shifters (tranny, toybox, t-case: H-L, t-case: 2wd-4wd)


Here's a link to my mini-website with several photos of the Toybox before and after install...

http://home.comcast.net/~cmilliron/wsb/html/view.cgi-photo.html--SiteID-610386.html

For me the toybox is great, set it in low range 4.7:1, leave the T-case in high, and crawl all day long... very seldom do I ever feel the need to put the t-case in low...

Whatever you decide to do, it should beat the heck out of working..!!! otherwise don't do it..!!
 
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Sorry Dislexia Kicking in, its a 76, cant you tell by the pic, smart ass..

Cmilliron - Thanks dude, Yea id rather not have to mess with the Tranny and moving motor and everything elce forward.. sounds like a good setup though.. Nice Cruiser too.. all the fab work looks Sweet, i wish mine turns out that good.. Would the stock tranny Toybox and T-case setup move make my Rear drive shaft too short??
 
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I would go for stock rearend gears with a SM420/465 to a 3 spd case. With 35's and stock gearing you will get decent highway, and you shouldn't have any trouble pushing 35's around town, and with the granny gear of either a 420 or 465 you will be able to climb like a mofo, all without having to move your engine or any of that nonsense. If you drive around town a lot, a 465 would probably suit your tastes better than a 420, but 420's (and especially their adapters) are much cheaper than 465's.
 

Poser

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Completly depends on the amount of cash you are willing to drop on this, and what you REALLY want to do with this truck.

I would figure out what type of wheeling you are going to be doing, and how much of it(every weekend hardcore stuff, or more street and light off road), the terrain that you intend to run in moajority of the time, and go from there.

You will have to make engine mounts, so "moving the engine" is not that big of a deal, besides, if moving the engine forward is a concern, are you having someone else do all of the required fab work? ( Shakle reversal, spring over, cut and trun front axle?)
 
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i would use a 4.7 to 1 gear set b/c you will only really want the very low gears off road in 4wd/4wd lo. the 4.10 will give better gas mileage and less wear on the engin at highway speeds. new axel gears will effect the car all the time. thats my 2cents
 
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[quote author=isotel link=board=1;threadid=6364;start=msg51674#msg51674 date=1066338041]
Sorry Dislexia Kicking in, its a 76, cant you tell by the pic, smart ass..[/quote]
I could tell. I was testing you. :D

Actually thought maybe you had more than one. 8)
 
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[quote author=isotel link=board=1;threadid=6364;start=msg51674#msg51674 date=1066338041]
Would the stock tranny Toybox and T-case setup move make my Rear drive shaft too short??
[/quote]The rockbox is only like 5 inches long and you can regain 3 1/2" for free by flipping your rear springs around. I see you are 350 so you probly already moved your drivetrain forward a few inches. If so, you have room.
 
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[quote author=Poser link=board=1;threadid=6364;start=msg51736#msg51736 date=1066347059]
Completly depends on ... what you REALLY want to do with this truck.

I would figure out what type of wheeling you are going to be doing, and how much of it(every weekend hardcore stuff, or more street and light off road), the terrain that you intend to run in moajority of the time, and go from there.
[/quote]I would agree with Poser. If you want a trail rig / daily driver you'd be more than satisfied with a 465 with the 3 speed t-case. If you want a serious crawler the rockbox or toybox will fit in the mix quite easily.
 

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[quote author=wngrog link=board=1;threadid=6364;start=msg51827#msg51827 date=1066360917]
Automatic all the way. Get the 700R4 to 4 speed case adapter and be done with it.

I would NEVER go back to a stick for the trails....
[/quote]


Was hoping that you would chime in on this Nolan. I can not wait to start my new wheeler!!! 350/700R4/Atlas/60's/coils

FUNTIME!!
 

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I would be careful with the automatic setup on a 40. If you plan to stay SU it probably won't be an issue but if you decide to one day go SO the driveshaft lengths could be a problem. I would guess the auto's would work better in a longer vehicle, like a 60. Not saying it is impossible but probably much more work involved to get it right. I also don't like the SM465's, I am sure I will get flamed for this one but I ran this setup with an AA overdrive unit for awhile and the SM465 was noisy on road and didn't have the overdrive gear, thus the need for the AA OD and the noise from this POS was amazing, a consistent whining on the freeway. Since I installed a earlier lower geared nv4500 and love it, lot quiter, 5th gear included and now my driveshaft is longer. If you are building it for the trail only none of this stuff matters but I built my for the street as much as for the trail. Hell, if I was just leaving it for trail use I would of stayed with the straight 6 and SM for sure, great combo for the trail. Let me know how else I can help. HTH.

Noah
noastoy@san.rr.com
 

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Trevor-The absolute best bang for the least cash is the SM420/3speed transfer combo. It will bolt up easily to your chevy motor and you may or may not have to change your drive line length. That 420 is a little clunky shifting in town but the trail gears are perfect. Mine has made 3 trips through the Rubicon and it's a good match for that terrain. If you arn't going to wheel it though, I would just stay with the stock set-up. The stock 4 speed is actually pretty smooth shifting for a truck tranny. Good luck.
 
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Thanks to everyone, Previous to this i was a Stock Toyota minitruck (Beat it till its dead) sorta wheeler.. Whatever i do i will do it all at once, Spring over, and Gearing.. so i will need some custom drive shafts anyway.. What Gears are in my Axels Stock.. (76) and Are the Rear Springs on it Offset (front eye to axel shorter than rear??? )) If so i will be fliping them to get some more Length out of it.. Thanks again
Trevor
 
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I stayed with the stock 4.11 gears and am running 35's pushed by a 350 and stock 3 speed tranny. I will be putting in a sm420 this winter for the low end. Right now, the cruiser will do every bit of highway speed that I want to do and have some in reserve. If money were not an issue I would run a NV4500. Great low end and a .75 overdrive. For now I will stay with the Sm420 and try to pick up an AA rockbox in the future.
 
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I'm SBC 350, 35s, 4 speed, stock 4.11s and also wish I could afford the NV. Saving for a rock box for the DD. Runs down the highway pretty good as is. Am thinking about putting a 465 in being as I just exploded a pilot bushing. Never seen a pilot bush fly apart before. I think my 40 wants me to do the 465 right away. I was going to wait till snomo season but ...oh well. Have a doubler for my wifes rig but due to length issues I can't go the same route. Unless I seriously alter my wheelbase, then I could use her parts on my...hmmm...where's that measuring tape? ;)
 

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