I am planning on going to 5.29 in the future in order to run 35's. It has been suggested that i keep an eye out for some 3rd's off a 6cyl, so i can run the heavier duty gears.

My question is, are front and rear 3rd's interchangeable? Since I have the solid front axle, I'm not sure what my chances of finding a 6cyl front 3rd are...unless i could use a rear on it...then i could just find 2 6cyl rear 3rd's...is this making sense?

any advice would be appreciated

thanks
chuck

 

I know that 6 cyl are only on IFS suspention so you won't find a 6cyl front to fit.
I also don't think that going with a 6cyl thirds are worth the extra effort. I will be going to 5.29's also and the only reason i would go with a 6cyl third would be to put a IFS rear axle sense they are wider. Other than that don't worry about it the 4's are strong enough, and if you want them stronger than get them freezed.
B

 

freezed?

 

The 6cyl should fit in the solid front but if I remember correctly you have to hammer out the bulge a little more since the 6cyl gearset is deeper than the 4's.

James

 

Wow... interesting responses.

6-cyl diffs were available in 86-87 Turbo trucks and 88+ V6 trucks, BUT it's important to verify that it's really a 6-cyl diff and not trust the door tag.

The diff fits front axles and rear axles w/o a problem. Only recommendation is to clearance the ring gear cut out on the mounting flange - about 3/16" or so - to make it easier to get the diff in and out. Been there, done that.

4-cyl diffs are pretty stout, but of course, anything can break. If there are concerns about breaking the gears, have them cryogenically frozen by Bobby Long.

 

rock...could you explain this a little further to a newbie? thanks!

 

so, should i just save some cash and buy the new 4cyl yukons from bobby long that are already treated with heat and freezing?

 

are you worried about the gears or the carrier breaking? The 4cyl and V6 gears are identical in strength its the carrier thats different. Properly set up gears won't be your weak link. If you're going to be locked with a detroit or ARB in the future just get the 4 cyl because you'll be replacing the carrier with one thats stronger then both the stock 4 or v6 ones.

 

makes sense. think i've convinced myself to get yukons from Long.

 

The housing is stronger on the V6. It has more strengthening "fins" on the outside, as well as being thicker. Like was said before, they are interchangeable between front or rear. Just make sure you don't buy a 3rd with the stock 4.88s unless you don't plan on changing ratios. There is a lot more work involved with changing the gears on a stock 4.88 3rd than on others due to a design difference in the carrier.

 

ok...2 things....
1) i have read that bobby longs gears are good, but that his treatment actually softens the gears (?) and though stronger, they wear out faster (huh?), so dont put them in the rear of a DD, but they are fine up front
2) which v6 thirds have the 4.88 so i would know what to avoid...or better still, what is the best vehicle to look for at a junkyard to find what i need?

 

i bought a set of 4.88 3rds for my '79 truck, both are factory. i don't beat on stuff too much, so i don't have to worry about them breaking. one only has 38,000 miles on it, too.

to fit one in the front, i had to grind the notches in the front axle a little more. the flange is double thickness, the lower layer didn't have as big of a notch as the top layer. a couple minutes with an angle grinder fixed that. other than that, no problems. the gearset isn't physically larger so there is no other clearancing necessary.

 

The 4.88s came in the V6 automatics that came with 31s from the factory. They're just as strong as the other gears, they're just harder to change the gear ratios in. I had to do minor grinding on the axle housing to fit my V6 3rd as well, but that wasn't hard at all.

 

so i am gonna be getting all this stuff from a guy for what seems like a fair price to me...

V6 3rd member from 1994 4Runner 4.56 gears (just for the housing)
Brand New Detroit E-Z locker for V6 Toy 8" diff still in box
Solid pinion spacer/collar for V6/turbo 8" diff brand new, includes 10 shims

i'm not sure about what a pinion spacer is or why/if i need it
but i'm gettin the whole shebang for 225

any thoughts or comments?

 

actually, the 4.88 toyota gearsets are the only thing that'll go into these. the pinion offset is different so it uses a thinner ring gear. carrier is the same as a standard V6 though, so you can lock them.

 

yeah, after reading up on those, i found out you can only put 4.88's in, so i am trying to avoid those housings.

any opinions on post #14?

 

that's a steal at $225. i paid $190 for my ez-locker.

you don't need to do any shimming or pinion bearing work if you install that, though. all that needs to be done is re-set the backlash.

 

cool, thanks kyle!

 

As I said, it takes some work. You have to grind the carrier in order to fit any other ratio. It's not fun, but many people do it. That's why I suggested not getting a stock 4.88 3rd if wanting to regear.

 

That is a very good price for what you're getting. The solid spacer is stronger and works better than the crush sleave when using a locker, but is much more work to set up initially. I'm pretty sure we used the crush sleave in mine when setting it up 8 years ago. If my memory serves, you will need to remove the ring gear to install that locker in a V6 3rd, but you won't need to mess with the pinion at all if staying with the same ratio. I really like having a full locker in the rear on my Runner, but it is no longer a daily driver. I wouldn't trade my ARB locker in the front for anything else though.