Go drive down the interstate in S4 to give yourself a real good idea what regeared topend will look like in D/5th. Your final drive ratio will still be geared lower than where you would actually be but sure put me at ease about turning too many RPM on the highway. S4 on stock size tires is turning 2700 rpm at 70mph. Regeared in 5th would be turning slightly less.

Any advice where to buy or who to do install on 4.56 in UT? A local shop quoted me around 1400 and also stated nobody made 4:56 for the late model 5th gens. I didn't bother to pry deeper because I swear several members on here have had theirs done

The problem is.. when it comes to truly difficult high traction obstacles... You have two choices. Wild driving (with body damage and parts on the ground) or lockers. I choose lockers, but to each his own style.

If you are not doing really difficult stuff, well then no need for lockers at all. Most 5th gens don't need them as you can do quite a bit without them.

I maintain that it is not asking for trouble... Going out and wheeling your rig in difficult terrain... is asking for trouble. So stay home or just don't worry about it...

That's not really true. According to this gear calculator http://http://www.grimmjeeper.com/gears.html you are 1,998 rpm at 70 mph with stock (3.73) gears and tire size while turning 2,361 rpm at 70 mph with 285/70 tires and 4.56 gears. You would be turning 2,775 rpm in 4th gear with stock setup.

You really don't lose too much running at highway speeds and pick up so much responsiveness and driveability.

Lockers really do make a difference. My experience is driving style and tire size make much more difference when it comes to broken parts. My observations say once you go to 35" tires on these trucks things start breaking. In the past 30 days I've seen a broken CV axle and a broken rear ring and pinion on two different trucks with 35" tires. Both cases where not due to wild driving and both did not have front lockers, though the rears were locked in both. I have seen similar broken parts on trucks with 33" tires, but driving style was the main cause - blasting up rocky hills while wildly spinning the tires, some locked at both ends and some not.

If you need a front locker you are most likely in some very technical terrain and slowly picking your line through, not blasting through.

Nitro makes 4.56 gears for the 5th Gen and 4.88's too. East Coast Gear does a core swap that's relatively reasonable. I had mine regeard for $1,700, all in. That's relatively cheap and it kind of depends on who you know. East Cost has core swap pricing on their web site, but you still need to R&R the rear 3rd member and front pumpkin. That will save on installation cost.

I paid $1,000 for the gears and master install kits and $700 for installation, but I got very good deals on both, saving at least $600 overall. My son is having his 4th Gen done as we speak (he blew his stock rear ring and pinion last weekend) for approx. $900 all in, but again, it is who he knows. If you pay retail for the gears and install it could exceed $2,000 very easily. Even at that price I feel it is worth it.

Agree, 4th gear on hwy stock gearing is equivalent to 5.18 gearing in 5th gear. 4.56 is quite a bit different. It is a 400rpm difference from stock in 5th gear.

Don't forget. These truck are not all the same. Many people package FJs and 4th gens into the same group. They are similar, but when it comes to the rear diff... big difference. The 4th gens and older FJs will break the rear diff pretty easy. The newer rear diff seems to be much stronger. I've seen many broken Toyotas.. Still have not seen a 5th gen rear diff fail.

I see two different choices, picking the right line and employing skilled two pedal driving, or taking the bypass. I won't break my rig either way. There have been very few instances in my wheeling experience where I think a front locker would have really helped.


True statement. Cheers!




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Good point. The 4th Gen and older FJ's had the 8.0 rear, while the 5th Gen has the 8.2. I haven't seen a broken rear diff in a 5th Gen either, but I have seen broken CV axles.

No doubt Cvs are the weak point, but that is somewhat a blessing as they are easy to replace on the trail..... They still seems better than the 4th gens and early FJs as there was a revision.... RCV had some at one point... but they had problems with the boots leaking. It should be pretty easy for them to make some that are bomb proof... but then the diff breaks ;-(

So it feels like SAS would be the smart option at that point. The IFS works fine for crawling... If you need to use momentum and a lot of wheel spin. Solid axle is the only way.

I think I know where you probably wheel often Barnwell? I've done every trail there (in my trail rig). even dWoody or whatever it is called. That type of terrain is very solid axle oriented.. All that loose crap that just falls apart under you... Still have red dirt in my rig....

Attached picture of my buddy going up Dwoody. I did it to, but he screwed up with my phone and I got no video or pictures ;-( Talk about a trail that has gotten harder.... Shit is scary now. We even got another friend of ours up in an FJ80 on 37s. I'm still shocked he made it.

Attached Images

 

what are your rpms at 80 mph in 4th and 5th gear?

Yep, Barnwell is the home park, but I hit Bridgeport just as often and spend a few weeks each year is SW Colorado.

I've done most of the trails out there, either in my rig or as a passenger. Majority of those trails can be done by a lifted 4Runner on 33's and a rear locker as long as you don't mind body damage. Lots of off-camber. I've done D'Woody a few times as a passenger in a buggy and have seen a lot of built, early pickups do it, but all on straight axles and at least 37's. My son is about 75% complete on an '89 SAS'd 1st gen. It's sitting on 35's now, but will end up on 37's by the time it's running.

Follow the link I provided in one of the above posts.

I have down that. I was asking for real world rpms, not calculated ones.