Sidewayz6.0

I have a 4.30 in my stock 8.8 rear end. I don't see why you couldn't go bigger than that.

minnow81469

Lol i put 4.10s in my 95 and pulls like crazy anything can be done depending on your year you dont have to put a different posi in. auburn lockers are alright but i put in an eaton posi in and could tell a huge difference you need speedo gears in your tranny to they are cheap otherwise you cant tell how fast your going it will read like 20mph over what your actually going

wildcobrar

I have 4.30 gears in my 1990 Mustang. They install in the same manner as 2.73, 3.08, 3.27, 3.55, 3.73, 4.10. I believe the 4.56 gears need a special differential pin because the Crown or ring gear is thincker and the pin will not slide by the Crown/Ring gear. The pin I mention has a FLAT machiined into one end to allow it to clear the Crown/Ring gear during assembly.

On another note, if you run C clip eliminators you have just bipassed the differential pin (as this pin is no longer needed to assist in keeping the axles in place) issue on numerically higher gearing installs,

Joe

cch

Just an idea. But since the rear is already tore apart and you're changing the clutches and what not, maybe it would be a good time to replace everything else such as springs, bearings and races; make it all "bullet proof". I changed from 3:55's to 4:10's last year, I was amazed at the difference let-alone going from 3:08's. You'll have fun. Anyhow good luck bud.

minnow81469

I agree with cch do it all while its torn apart then you dont have to worry about it later on and it shouldnt be to bad on the old pocket book

Modular_Madness96

I have 4.10's in my 89 in the 8.8 with a new factory T-Lok unit from work and they went right in with no issues.If you dont want to spend the extra on the fancier clutches do what i did and just add an extra clutch to each side instead of 3 i have 4 makes it a lot harder to break loose.

BTW i have a PA C4 and yes you can tell a huge difference it was like night and day even going from the 3.73's i had before.

Hamutoff

To ALL: I was wondering what the concencess is; my statement was that that all gears up to 4.30 do not require modification, whether pin change, c-clips, machining, etc...
Is this correct? I got into the question years ago when bud and I building el-chepo 89 nitorus lx and I was guided to the point that 4.30's were the numerically highest that would "drop in as stock"

FLcracker9

You are correct. I installed 4.88s in my Son's F150, which required using a notched cross pin. Unfortunately, the notched pin is weaker than the standard pin (obviously due to the notch), and under heavy use, the pin can break (I'm speaking from experience). This happened to the truck 3 weeks ago. The pin broke and when the Trac-Lock spun around, the pin hit the housing and split the case in half, and shot the pin out of the diff cover. I was able to buy a used Trac-Lock from a local 4X4 shop in my area, and the owner advised me to never use the notched cross pin, but use a standard pin by beveling 1 or 2 teeth on the toe of the ring gear where the hole for the pin is (with a die grinder). Grind enough of a bevel to allow the standard pin to clear. He's done hundreds this way over the last 17 years with no adverse affects on ring gear wear/strength. I did exactly that, and so far no problems (it's a daily driver for my Son). Just something to think about if for some reason you were contemplating going 4.56 or lower.

fastfox86

There is also a different procedure out there for re-packing the clutches so that they will grab a little harder that a lot of people use when re-building their stocker rearend. I'm not exactly sure where to find it though. Anyone else know where the procedure can be found?

FLcracker9

This is one I've posted before

http://www.youtube.com/watch?v=0GsLDg3C6Hc

I've used this on my last 3 builds, and it works great.