I've been searching and I know this has been covered a bunch but I still have some questions.

Gear ratio calculator comes out to 4.63 or something. So I'm planning to get some 4.56's and keep 35's on the truck. This should help mpg for my ride to work and give it a little more umph.

How well do 4.56's do with 35's, I think Beard ran that setup for a while?

If you disagree and think I should go to 4.88's please speak up. I'm here to listen.



Now..spline count??

I know that most lockers available for the 8.8 are for the 31-spline axles and not the 28-spline. So I'll probably be getting a 31-spline before long.

Would the same gears that work for the 28-spline work w/ 31-spline??

I know I have more questions just can't think of anymore at the moment.

Thanks.

 

an 8.8 is an 8.8 whether its a 31 spline or 28 spline axle shaft. its still an 8.8" ring gear.

so yes they will work on both.

Lockers there are several 28 spline ones out there too.

4.56s are nice, its close to stock but not the same. I went overkill on my 37s with 5.13s and I like that much better. Personally if i could do it again 4.88s for 35s.

I did drive a lot of highway with the 4.56s and it was fine, it did fine off road but not what I think it could have been with 4.88s.

I would go a bit higher for sure. 488s I dont think you will regret it.

I ran 4.56s and 35s for 40k miles? worked great really, wasnt slow, wasnt fast, still did the job fine but I think I would have been that much happier with 4.88s. If you do a BUNCH of highway 75mph or faster better get 4.56

 

I myself am going to go with 4.88s. Unless you do a little more highway driving I suggest the 4.88s over the 4.56s. I'm not sure if you have auto or manual tranny, it will affect the decision and someone is going to ask here soon.

If you're asking if a ring an pinion set will work with both the 28 and 31 splines, yes. Doesnt matter, it's still the same gear sets. Make sure to get a notched cross pin when you upgrade your gears too.

 

grind the gears down, notched cross pins are weak

 

I have an automatic and drive about 60 highway miles a day.

I can get a great deal on the 4.56's, but would have to pay full price for a set of 4.88's. Probably a couple hundred dollars difference, that's why I ask.

Thanks for the quick replies.

 

definitely go 4.56s then. You will be happy.

That is why i went 4.56s because I got a great deal on them.

 

Thanks guys.

 

yep....beard hit the nail on the head....


if you do alot of freeway high speed runs, get 4.56s. if not/maybe the occasional freeway run, do 4.88. there's noting like the crawl speed you have in low and 1st with 4.88's.

 

I'm pretty much going to agree with what has already been said.
4.88's would be more ideal. 4.56's would be okay still.
I ran 4.88's and 33's (4.0L auto) for a year. I loved in in Oregon (mostly 55 or 65 mph speed limits), and I drove mostly in town. It was awsome offroad or towing.
Once I got here and drove it on the freeway at 75mph it wasn't the best. But it wasn't the worst thing in the world either, and I only had 33's.
The 4.56 will work better for highway driving if you'll be over 65mph often for long periods.

Oh and I went with 4.88's instead of 4.56's because I got a deal on a front diff with a locker and 4.88's already installed.

 

I would rather go with the 4.88's because I've heard such good things about the difference they make. But I'll be getting a great deal on the 4.56's.

I usually run about 60-65 mph for the majority of my ride to work, about 30 miles each way. We'll see how it goes and hopefully I like it because I'll sas it before regearing it twice. I should probably just save my cash for the sas anyway. lol

 

You will be fine with the 4.56's... do it man.

 

Oh I'm still getting them. I'm picking them up tommorrow.

Still looking for a good shop to install them. I've got a couple in mind and had a few people offer to do it. So hopefully it won't be too long.

 

PM ranger1999 or whatever...he's got those brand new in box 4.56 yukons for sale in the classifieds here....he found a place to do his for like 300-400 total. he's in NC too. dont know where though.

 

That's who I got them from. I just got back from picking them up. Big thanks to Dustin, Ranger_1999, for hooking me up.

Can't wait to get them in the truck. Let me go get some pics.

 

8.8 install kit.


35 install kit.


8.8 r&p


35 r&p


Notched crosspin. Not sure if I want to use this or get a solid one.


Now I just need to get a locker so I can get it done all at one time and BAM!!!

 

Eew. Get a regular cross pin. especially if you're going to lock it. You don't even need a notched pin for 4.56 gears, do you?
If you do, it's better the grind the ring gear down anyway.

 

That seems to be the consensus. I'm gonna see if I can sell or trade the notched in for a solid one, I actually have two of them. Or can I just use the pin out of my 4.10's?? I would think they'd be the same right?

Now that I have the gears I'm actually thinking about seeing if I can sell or trade them somehow for some 4.88's. But that's just me thinking.

Yukon's site says with anything over a 4.45 something needs to be modified to clear.

Thanks for all the info guys.

 

You can use your current pin.

I'm running a notched pin right now...being open(until monday). Ive had two people in forum world tell me to put in a stock pin when i install this aussie. BUT, i've read that the aftermarket pins and notched center pins are stronger than stock pins...so idk yet. I actually like the notched center pin...BUT HATE the fact that i can't pull it out on my 4.88 ring gear. I know exactly why it's notched now and how much better it is to grind the ring teeth to get a regular pin in there.


oh...since you've got two notched crosspins, and it's complete install kits, i know exactly who you got your gears from... lol.

 

I keep looking at the cross pin and trying to picture how it will sit in there with an automatic locker, wondering if it would even work right...
It seems like it would allow the c-clip retainer cup to move around, if I'm picturing everything right in my head.

 

Wait, maybe I'm thinking wrong, lol. The bolt goes through the center pin on the side, so the notch would be facing "up" or "down" if you slip the center pin in from the back of the case. I suppose that would work fine.

Here is one half of the aussie locker assembly. With everything in there though, I still can't picture how a notched pin will allow you to get the pin in between, since there is such a small tolerance.

 

it rotates in the carrier..with the notch facing the axle shaft.....it gives you ample space to install the c-clip while the notch is facing the shaft. rotate 180, install other cclip, then rotate 90 and the unnotched sides of the pin push the shafts outward. BUT...there's no way to install a locker with the pin being unable to be removed from the carrier. i know you know this already. lol.

it'll work with an autolocker i'd say..like a lockright or an aussie...because the notched portion is in 'dead space', and the unnotched sides next to the notched portion are being used against the shafts. look at the pin pic...you can see the hold for the retaining bolt is on the same plane as the notch.

my pic sucks for what i'm trying to explain. lol. but the notch is facing the camera, the way it'd be installed in the carrier.





EDIT: I see you edited too brian. lol. I completely forgot the tightness of the center pin when installed in an aussie. One thing good though that MIGHT help...the bottom of the notched pin has a slot in it...a slot to aid in rotating the pin in the carrier. But by the time the pin is installed...the axle shafts and cclips are already installed..so...i think it can be used. but...we'll see. i got both styles at my disposal come monday. oh...and Matt/Seed...you betta believe i got pics when its all said and done.

 

I still need to do some more research on the whole pin deal. I definitely want to go the strongest route.

Got a great deal too!!


Thanks for the pics and info guys.

 

use the stock pin!!!! it will slide right back in there. if anything you will have to grind some of the teeth on the ring gear like Brian did. You can see the difference in those teeth in his pic.


parts look good. I am so glad I have not had to mess with gears/lockers in almost a year now. It is fun though.

 

I can handle that. Thanks.


Shane, where are your pics?!?!?

 

Alright, so I contacted Chase up at East Coast gears, great customer service, and he is willing to let me trade the 4.56's straight up for some 4.88's.

Now I just need to find me an expo axle with rotors to put them in!!

HELL YEAH!!