My 3.4 swapped 95 4runner with long fields is slowly creeping up there in weight, at about 5000 lbs with my gear and spare tire. I'm running 5.29s, arbs and high pinion front.

While I don't wheel extremely hard, and have not found the limits of my 529s I do know with the weight of the rig and the 37" toyo mt's that it is quite possible to see a ring gear go pop as 5.29s aren't amazing for strength.

With the 9.5" ring gear is it worth the time to swap over from the mini truck stuff? I have the axles in an 89 FJ a buddy has for parts.

I'd be centring the rear axle and using 95 4runner shafts (to do away with the c-clips as well). The parts I like about the swap are

1) I can reuse my longs with just buying a longer inner shaft
2) I can reuse my high steer arms and trunion eliminator
3) Gaining 1.5" a side and losing the wheel spacers

Parts I dont like:

1) Pinion is the same diameter and seems to be the weak point of that axle.
2) Having to buy new lockers and gears (I'd probably go with 4.88s)

 

That sounds like a nice upgrade.....go for it.

9.5" diffs are stronger than 8".....even the 27 spline flanges that slip on the pinions don't shear on the big 9.5" 3rds.....none recorded on the internet. So pinion strength is not a concern. What is always a concern is the gear set-up ..... even though it is a massive 9.5" ring gear.
What's your plan to center the rear FJ62 housing?

I put a 1985 FJ60 front end under my 01 Tacoma and made the right decision https://www.yotatech.com/forums/f152...tacoma-283930/

Might still put the bigger rear end in but not sure.

 

Hi Zuk! Thanks for the reply.

From what I'm finding on my research, the pinion seems to be the fail point, as they use the same diameter pinion as the mini, just with larger heads moving the weak link from the teeth.

https://forum.ih8mud.com/threads/bro...-shaft.405114/

Ive always wanted to ask you Zuk, do you feel the amount of pinion teeth/ring gear teeth on 5.29 gear sets compromises the "meshing" or contact (because less teeth equals more stress on a single tooth)? Reason I ask is I keep hearing how sets like 4.88s or 4.56s are stronger because of the fact they have more teeth in contact at a time. Im debating going to 4.88s for this reason, although I prefer 5.29s.

My plan for centring the rear is to use some mini truck tubes, cut the LC axle tubes off and slide the mini tubes into the larger inside diameter LC centre chunk. Bolt on my 2nd gen 4runner shafts to the mini tubes and slide in until I can see the splines in the spider gears (remember LC axles have a removable cover like a dana 44), and burn it. While doing my best to keep everything square. I'll find a link to a write up.

https://www.yotatech.com/forums/f88/...-build-276833/

Im mainly wondering if its worth my time to spend the money to do it or if I should just save for some dana 60s. Does anyone know if there is much difference in ground clearance on a LC fj 62 axle/diff compared to a dana 60?

 

well, guess I should have put more conditions on the pinion spline breakage. I also have heard and saw pics of a 8" 410 rear end that snapped the splines off....It was on a rockcrawling forum and the thought process of some at the time was that 410 gears are stronger so why not just run the 410's and slapped a double case in there with 4.7 reduction in the rear case?....Well, they quickly found out that the stresses were now unbalanced and the break point simply shifted up the drivetrain from the ring gear tooth to the pinion shaft.

That link you posted, the guy was running a 383 ci chevy with a manual tranny into "low performance" 373 gears and that adds up to instant shearing....in spite of the modest 32 inch tires. Low performance simply means no real torque multiplication.

The higher the numeric gearing the easier life is on the splines....all about balance....and with 37" tires the balance equation says 529 gears. The splines will never break with that combo. Auto trannies allow ALL driveline stuff to live much longer.

As far as the debate.....contact ratio is about the same whether it's a 410 or 529 or even a hi-performance 571. What's more important is to use a top shelf brand(Nitro or G2) and set the depth "slight deep" and dial in some carrier bearing preload on the carrier bearings in particular.....pinion bearings less critical. Contact ratios are not published. A hypoid gear always has 2 teeth in contact during the cycle. The 3rd tooth that is making contact for most of the cycle is influenced by numerous parameters.

Yes, I'd stay with the genuine Yota axle housing. If you do what you say on the centering and keep everything in spec then you will have an awesome CENTERED 9.5" which few can claim. 30 spline axles are somewhat limiting but they make chromoly.....

 

Thanks for the info Zuk, I feel like id much rather deal with a broken axle shaft then a ring and pinion failure. While I know a shaft going can take out lockers and more, I'd rather play the odds instead of just taking out the R&P.

Have you worked on Dana 60s? Any input into how much ground clearance you save (or don't) with a cruiser axle compared to a 60? If there is no clearance gain with the cruiser axle it might be wise just to head to the dana 60.

 

Auto tranny? If so, you won't break 30 splines.....the joys of having a slush box

Limited experience with Dana60 but I know they have a lot of beef....35 splines and all that.....they do have a lot of meat hanging down under the ring gear but that can be fixed with a nip and tuck. Ratios match with 488 but not quite with 529.

 

with mini-truck front axle housings, it's not a question of if the housing is bent, it's just a matter of when.

so i'd be looking at that as a reason to do the swap, before worrying about the 5.29's.

maybe call up brian at fror, he's been turning out a lot of heavy-duty front end stuff, including even brand new knuckle balls: http://frontrangeoffroadfab.com/diam...knuckle-balls/