88toypickup

I recently bought a 1985 axle and am planning on doing a swap sometime in the next year (hopefully). I am on a tight budget and was wondering if anybody could help me out. My question is will a 4cyl differential hold up to an 36" tires and a locker with 5.29 gears and a pretty much stock 22re? I don't want to spend the money on a high pinion and I already have a 4cyl third. I could put 5.29s in the 4cyl I already have and run the 36" Iroks I already have, but I want to do thing right the first time. I would rather save up for a high pinion then have my 4cyl break, but if the 4cyl will hold up, I would rather just keep it. Oh, and the same goes for the rear, 4cyl or v6?

Cargun

4cyl 3rds will be fine as long as you have a fairly smooth driving style. On a stock front axle, the birfields, axle shafts, and probably even the hub studs will let go before the 3rd if setup right.

I ran a 4cyl 3rd with lockright for 1+ years in the back of my 4runner before swapping it into the front of my wheeling rig 3 years ago with 36" Iroks, 4.7:1 t-case, and V6 engine. It's still holding up fine.

If you ever start blining your rig out with a set of aftermarket birfs, axle shafts, hub studs, etc., the stouter 3rd is a good addition to that package.

netwt12

the 4cyl will be fine. you'll blow a stock birf before you blow a diff anyway.

waskillywabbit

iTrader: (-1)

4 cyl will be fine. Buy Longfields.

tc

Same as above.

The difference in strength between the 4cyl and V6/turbo diffs is real, but pretty small.

High pinion will be ~30% stronger in the front and have better clearance than the low pinion "normal" diff. I would say these differences are hugely significant, but are probably not necessary if you're not hard on parts. If you ARE a "breaker", then you might want to look into it.

I can tell you Molly's diff with 5.71's has been stronger than the manual hubs and both stock Birfs!

Blizzard

HP diffs are great when you have single T-Case.



Mine is from a Toyota LJ-70 (You don't have those in the States eh?) but now I've bought a 80 Series LC one with E-Locker

David

1styota4X4

not trying to be dumb...but what is the difference between a high pinion front and a standard front? I thought they were the same

tc

Ummm ... a high pinion has a high pinion.

Instead of the pinion being BELOW the centerline of the ring gear, it's ABOVE the centerline. Obviously, this helps with ground clearance, but only by an inch or two. In FRONT applications, this changes the setup from being on the coast side of the gears to the drive side, which are approx 30% stronger.

3rd gen 4Runners and Tacomas have high pinion fronts, the older trucks had low pinion. The desirable option is the high pinion 8" elocker out of 80 series landcruisers

ryantowry_81

but note these are IFS trucks and are not the same hipinion that can be used in the minitruck strait axle, the one that fits is out of the 80 series landcruiser.

khoopes

OK I am learning something here.. can I ask some questions??

What are Birfs?
What are longfields?
When switching from 4.10 with a 41 tooth ring gear and 10 tooth pinion to 4.56 with 41 tooth ring gear and 9 tooth pinion can I just change the pinion and reuse everything else?
What is the difference in the 4 pinion and 2 pinion toyota diffs and the 4 and 2 pinion diffs with LSD (I assume means limited slip differential) and can the LSD be used in place of a locker? ( am barely familiar with diffs, my concept of them comes in three flavors, open, posi trac from the muscle car era where they are always locked but have clutches, and "locking" Chevy diffs I have used that lock after you spin em at a high enough RPM.) Does any of this apply in setting up my new diffs? I am asking because I am considering the purchase of a so called limited slip differential and regearing it as my rear instead of the open turbo rear I have now.

Thanks!

khoopes

Bump. Am I a thread killer?

netwt12

"can I just change the pinion and reuse everything else?"

no the ring and pinion come as a matched set.

birfield is the name of the outer axle. instead of having a u-joint so the wheels can be turned like a traditional dana axle the toyota axle has a birfield which has a cage with ball bearings that allow the outer shaft to pivot. longfields are a type of aftermarket chromolly axle that have more strength than stock dana 60 axles. they also have a lifetime warranty when combined with their hub gears.

http://www.longfieldsuperaxles.com/

khoopes

Ha, OK, I am getting the picture a little. Since I have an IFS I was a little confused... hope someone can answer my other questions about the toyota diffs and lockers/lsd..

ryantowry_81

As for LSD they really dont do much for serious wheeling because they dont give you a positive lock up. it will work for a little extra traction in mud and snow but useless on rocks and any crawling.

tc

www.longfieldsuperaxles.com

http://auto.howstuffworks.com/differential.htm
4 pinion has 4 spider gears
2 pinion has 2 spider gears

khoopes

OK so now I have a used ring and pinion for both my front and rear diffs in 4.56, but my respected mechanic (dad) says he would never reuse a ring and pinion in a different differential. How about you folks??

muddpigg

iTrader: (1)

Hi pinion uses the same guts as a V-6 dif, the gears are reverse cut. So are stonger when run in the front since the are run on the drive side (high pinion) as opposed to the coast side of a 4cyl 8" dif. Also better ground clearance and better DL angles.

Might want to search facts here and on pirate all this has been reveiwed many times

But since this is YT and we are kinder and gentler than the other sites, I'll do the searchin for you and save you the effort. http://home.4x4wire.com/erik/diffs/ there's much more information out there.

muddpigg

iTrader: (1)

Birfeilds will probably be your weakest link. My buddy runs older style Longfeilds (roughly x3 stronger than stock) on 37" without issue but he relies more on technique and gears. Another buddy ran 35" on stock birfeilds and drove buy skinny pedal always broke birfields like constantly, stent more on stock birfields than I paid for a used set of Longfields.

tc

Absolutely no problem reusing them IMHO, but why not just get the diffs they were in and not have to do the gear setup again?

Windsor

I apologize for digging up a nearly year-old thread, but I have to ask...

Why the *bleep* are they called "2 pinion" and "4 pinion" when the differential always only has one pinion?

Why can't they just say "2 spider gears" or "4 spider gears"?

edit: nevermind. "pinion gears" are simply small gears that talk to a "ring gear". bleh.