new gears for the 87 thinking 4.56s should i add a locker?

[weider1717]

my truck has an open diff and currently has 35's thinking about going with 4.56's should that be a good choice for the 35's? should i add a locker or would it cause the rear to blow easier with the 35s? the rear is the original 10 bolt.

[crashz]

The big deciding factory on the life of your 10 bolt is your right foot. The 10 bolt in my 2004 lasted 180K miles with essentailly 32" tires. Towed, plowed snow and all kinds of stuff. That also had the G80 locker that could be a bit harsh when engaging. No issues at all.

I had 35's on my 83 with 4.10 gears and found that a good combo for everyday driving and moderate towing. If you have OD, 4.56 is fine, but it might scream a bit on the highway without OD.

[meatwagon83]

A locker is always a good idea!

[Rubble]

I have 2 trucks on 35s,one with 6.2/833 & 3.73s.The other 350/465 & 4.10s.Unless you have overdrive,the 4.56s will be pretty high revs on highway.The 86 with 4.10s runs about 2500 @ 100km/h...62mph. My crew has 4.56s on 33s,it's pretty well 3grand for same speed. 454/400/205

[1968vetL-71]

You'd be farther ahead just finding a 14 bolt from a cucv or so and just selling yours. Prob won't have much into the swap then. A cucv rear will have a Detroit locker already in it most likely. That's what I did. Nothing better than a straight up swap!

[Jake Wade]

Originally Posted by crashz

I had 35's on my 83 with 4.10 gears and found that a good combo for everyday driving and moderate towing. If you have OD, 4.56 is fine, but it might scream a bit on the highway without OD.

Good advice right here.

[dieseldawg142]

^^yeah, if you don't have overdrive, forget the 4:56's, i have the same set-up as Rubble in my crew, & it turns 3 grand at 55. even with 38" tires slowin them down a bit.
3:73's or 4:10's, depending on how you use & drive it would prob. make you happier.
and as far as i'm concerned, all 4x4's should have a detroit. couldn't imagine it without one.
but by the time you do all that ($) you could do like 1968vetL-71 said & swap in a locked 14b probably cheaper.

[weider1717]

anymore thoughts i'm leaning towards 4.56's even with the 32x11.50's I was running the 3.42's didn't seem like enough gear so I surely don't want to pay for a regear with regrets. It's an 87 so it has an OD transmission.

also if I have them install a locker would that be a bad idea in a 10 bolt running 35's? would it shorten the lift of it? I know an open rear normally is a lot less problematic and this is more of a show truck rather than a rig thats acutally used for offroad.

[dieseldawg142]

if it's more on road than off, maybe consider a LSD instead of a locker.
more forgiving & you'll never know it's there.
with OD, 4:10's or 4:56's will be fine, deciding factor will be how your driving it, & what your using it for.
personal thoughts, that's a lot of money to put in a 10 bolt. for mostly street, i would just re-gear & call it done.

[68Timber]

Use one of the gear ratio/tire diameter/mph/rpm calculators and figure out how much gear you can live with. Wallace Racing has some good calculators online.

[crashz]

I agree with diesel dawg, a limited slip will be easier on the axle and truck. For street use, it will be fine unless you plan on roasting the 35" tires. Which would grenade a ten bolt anyway.

The factory Gov-Locks use a 100 rpm wheel speed difference to activate. I always found that to be a little harsh and jarring, especially when one tire was on firm ground and the other with no traction at all. A couple times I thought I'd have to sweep up the peices of my rear diff after backing out of a snow bank. In my opinion a selectable locker or strong limited slip would be much better. The Eaton E-locker does both (LS when not activated, locked when active) and will be my choice some day.