fj40 suspenison lift

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

1

1978fj40

Joined
Jul 28, 2004
Threads
4
Messages
18
Location
oklahoma
hi i am new here, so thanks for all the help. i have a 1978 fj40, and i was wanting to use 4 inch lift springs, with SOA. on another forum, a guy told me that this would not work if i was going to wheel in my cruiser. is there any reason not to do this, other than the hi center of gravity? i also was wondering how strong the factory differentials are. i am looking into putting in a 350 from a chevy truck, will the diffs hold up, or will they scatter? i do usually drive mostly in water/mud. not many rocks around here, but will most likely try some when i get finished with this project. so what will work good for this?


thanks for the help
ryan
 
SOA with 4" springs = about 10" of lift...what tire are you planning on running?!?

I run a 350 TBI with a granny gear and stock diffs....fine spline pinions are not a must, but close (your 78 "should" have them tho), a rear wrap bar is a must, and upgrade those front axles to chromo inners and Longfields.

I run 38.5 SX's on a VERY low SOA with flat and worn stock springs...
 
well, it has the wrong springs on the back of it. i want to run about a 42-44 inch tire, still unsure, just started thinking about where i want to go with the cruiser when my t-case, adn tranny shelled a few weeks back.

thanks for the help
ryan
 
42-44 means Dana 60 axles.....period. Cruiser axles do NOT like that large of a tire, D44's are too weenie too. 14-bolt rear would work tho, but a D60 front regardless. You'd like the added width of the axles too for stability.

hit http://gallery.ih8mud.com and check the Moab photos from Pritchetts Canyon...two (or more) of the buggies in there are running Rockwell axles with 44's....BIG rigs.
 
what size of a tire can i run if i stick with yota axles? and what year of a chevy truck are D60, and 14 bolt axles in, i still need to find a donor truck for the engine and tranny, so my options are pretty open. i like how those rigs look, can you use the toyota springs if you swap axles? this was my main concern with wanting to use the stock axles, because the springs you can get for them. i do not have the money to do a 4 link, or anything of that sort.

thanks for the help
rayn
 
Opinions will vary on what your max tire size is...a few may even way 42's...personally, 39's are as far as I'd push, and even then, not a WIDE tire like a Bogger. My SX's are 14.5 and push the limit pretty hard (got real good at birfields and Newfield breaks for a while, and this year have junked 2 rear pinions).

D60 chev fronts were in the mid-late 70's....best buy would be a military truck, blazer or whatever...those were all d60 stuff.
 
i have heard that the military trucks have lockers in them already, is this accurate? if i can't find one of these, what is the easiest way to tell what axles are in the truck? i know the new danas have a rubber plug with dana written on it, but are the old ones the same? also how can you tell the different rear axles? i am not that familiar with this side of the vehicles.

thanks for the help
ryan
 
You have officially reached the "10 questions in a row answered by the Top Dog (administrator)" quota. This is an unofficial official policy of this website, as interpreted by someone who "sort of hangs out here once in awhile". No offence intended :D

ps - I'd chime in "on topic" but it's out of my range.
 
It sounds to me like you are jumping in with both feet and not letting the research guide you.

1ST, I agree with everything woody is telling you, take it as truth, I saw him blow a pinion on rock pile this year a CM04 (The man is a trail repair animal).

Second, 4inch springs and a spring over, you dont need all that to run a 38 inch tire (I could run a 38 on just my 4 inch springs) Fender trimming and a low COG are your friend.

I would step back and slow down and just start reading up on this at websites such as Ih8mud and Pirate4x4.com.

That is all, thank you

Dan
 
I read somewhere that 35's and above start putting stress on the axle that may lead to breakage, that 33's and below would not stress the strong axles stock in 40's.

The higher above the 35's, the higher the stress and the more likely breakage without beefing up the axle.

Anyone know if this is a good rule of thumb?
 
driving styles are more important than thumbs..I busted 3 stock birfs with 33's and two Newfields with 33's before breaking two more Newfields with 38's.

Rule of thumb states if you are willing to back out of every difficult situation, your odds of breaking go down dramatically :flipoff2:

45 minutes for a rear pinion (with my lovely assistant helping) is likely a record that won't be broken soon....
 
Woody,
Stupid question never being around some one with your driving style, but if you break a Birfield are you stuck were ever you are, or if it is in the front, can you disengage the hubs and limp home.

Thanks,

Ken
 
I've had all variations....and my repair "interest" always varies...I did a ride in MN where it broke and I opted to back down the 3 waterfalls we'd been up. I did one in Attica where I drove to an open spot and repaired it there, and ended up falling from 3rd in the group to last. Did one up north, jammed so I couldn't steer, pulled and left empty. Did one in Tellico, unlocked and winched up the remainder of lower 2, back to camp to replace.

"generally" speaking, you can unlock and get back....but often the birfield shatters enough to wedge chunks in the knuckle so you can't steer. Also, depending on the trail, you may risk damaging even more by continuing on with it broken.

On a bad day, it's a 45 minute job...on a motivated day, 20-25 minutes.

**** TOOL TIP - hit Walmart (or your SO's kitchen) and acquire a 1" wide rubber spatula. This is the BEST available cleaning tool for knuckles...BY FAR!!
 
Slowerthanu said:
Fender trimming and a low COG are your friend.
Click to expand...

This is the route I'm probably going to take. I would love to see more pics of Woody's rig.
 
BHCC017.JPG



Dscf0041.jpg



DSCF0027.JPG



DSCF0018.JPG


more? :flipoff2:
 
woody said:
more? :flipoff2:
Click to expand...

Keep'm comin :D

I would really like to see how much you angled in on the backside of the quarters.
Is that refered to as dovetailing?
 
woody you floppy bastid you :) thats a great style,GO TILL YA ROLL!!
shawn
yeah dude 4" springs soa means big trouble.stock spring soa with shackles and trimming can get you 42-44's but youll be poppin axles all day.
 
hehehehe

it only takes one rock to flop...funny thing about that pic is, we were only heading to lunch! lol

Fender trimming is easy....

pics of my rig at http://gallery.ih8mud.com in the Moab corner.
 
You must log in or register to reply here.

Share this page

IH8MUD Forum | Toyota, Lexus & Off-Road Community
Community platform by XenForo® © 2010-2026 XenForo Ltd.

© 2000-2026 Tie Rod Media LLC

Back
Top Bottom