going from 3.73 to 4.56

[GooseR]

ok, i have a 98 Xplorer 2wd 4.0L , I currently have 3.73 gears, and when i get my lift i want to put in 4.56's. I dont exactly know what i need but have been looking and found something that i think is 4.56 gears. http://broncograveyard.com/products/cat/20/161/32313V .. like i said im not sure what i need, im not sure if i have the 8.8 or whatever.. so if i could get some help.. thanks

Edit: or if you could let me know what(if any) vehicles come stock with 4.56 gears, that i could just get the rear axle from that.. that would be helpful too.. thanks

 

[unclemeat]

A 4.56 axle ratio is great for 33-inch tires. I also believe that with 2WD you can go with a 4.33 ratio. It is a good idea to check or replace axle seals and bearings, pinion seal and bearings. You may also want to install a limited slip or selectable locker gear carrier, or if you have the stock one, replace the clutches.

The lowest gear ratio in a stock 8.8 is 4.10.

 

[GooseR]

A 4.56 axle ratio is great for 33-inch tires. I also believe that with 2WD you can go with a 4.33 ratio. It is a good idea to check or replace axle seals and bearings, pinion seal and bearings. You may also want to install a limited slip or selectable locker gear carrier, or if you have the stock one, replace the clutches.

The lowest gear ratio in a stock 8.8 is 4.10.

so the easiest thing to do is to go to the junkyard and get a stock 8.8 with 4.10 gears....lol

 

[410Fortune]

not really, swapping the entire rear end for one with 4.10's is also alot of work!
You will have to bleed brakes, work with the parking brake cables, unbolt both leaf springs and shocks, and the driveshaft, then do all this again to get the new axle in there.
Also you will pay alot more for a complete 8.8 with 4.10 inside then you would just to have the right gears installed in your truck.

If you are going to run 33" tires get 4.56. 4.33 would also be a good ratio, especially if the truck is a 5 speed.

Use Ford gears, the ring and pinion will cost you about $180, then the master install kit is another $30-50. INstallation should be about $150-200 depending.
If you have limited slip now is a good time to have it rebuilt.

complete 8.8 axles with disc brakes and 4.10 gears from junk yards are typically $500+

 

[GooseR]

not really, swapping the entire rear end for one with 4.10's is also alot of work!
You will have to bleed brakes, work with the parking brake cables, unbolt both leaf springs and shocks, and the driveshaft, then do all this again to get the new axle in there.
Also you will pay alot more for a complete 8.8 with 4.10 inside then you would just to have the right gears installed in your truck.

If you are going to run 33" tires get 4.56. 4.33 would also be a good ratio, especially if the truck is a 5 speed.

Use Ford gears, the ring and pinion will cost you about $180, then the master install kit is another $30-50. INstallation should be about $150-200 depending.
If you have limited slip now is a good time to have it rebuilt.

complete 8.8 axles with disc brakes and 4.10 gears from junk yards are typically $500+

oh, because they charge 150 for axles at a local junk yard.. they have an explorer but not sure if its 4.10 or 3.73.. i might go check it out because 150 sounds much better than 400 bucks.lol. not to be cheap, but its a big difference.... but, bleeding the brakes, and brake cables sound easy. the leaf spring stuff is fine, because im doing an SOA soon, and i might get it before i put it on. and the driveshafts semi-easy to moderate.. this is working with my dad whos been a mechanic for several years back in the day, lol. but should i just get the axle? will a for F150 work with mine?

 

[99redXsport]

i have a 99 sport 2wd. what size gears come stock on my vehicle. and if i run 32 with a 3" lift would i have to change my gears to bigger ones or can i stay with what i have. i wont be doing alot of off roading just every know and then.

 

[Mascman]

My 33"s and 4.56s weren't really a good combo on the highway...4.10s would be fine.

Even with my 35s on, it still isn't that great for the highway...it still tachs out too much. I'd stick with 4.10s for decent all-around driving.

 

[410Fortune]

99redsport: They came stock with all sorts of ratios, 3.27, 3.55, 3.73, and 4.10
Most common on a 4 door 4x4 Explorer is 3.73

With 32's you will want 4.10's or 4.56 depending on the trucks use.

GoosR:
$150 for a disc braked Explorer 8.8? I see you have a 98, it is AWD?
You see the Explorer after 95 has discs, most of them have limited slip year axles.
The V8's and others also have traction bars built onto the axle.

So if you want a bolt in replacement you have some research to do.
Again it is EASIER to get the ring and pinion and have it installed.

OR

You can find the right rear for your truck, no a Mustang, Ranger, or F-150 8.8 will not bolt in. The Explorer also has 31 spline axleshafts, anything else would be a down grade.
If you are going to swap the entire axle out then you will want to convert the new unit to spring over, you will want to replace the parking brake assembly, and at the very least the brake pads, if not full calipers, rotors, etc.

I find it very hard to believe a Explorer 8.8 with disc brakes and 4.10 gear ratio, limited slip will be $150 at a junk yard. That doesnt mean it doesnt happen, I have seen one from a 2001 sport with only a few hundered miles on it total be snatched up for $150 so anything is possible. However FYI this rear axle is a very popular upgrade for Jeep YJ's so the junk yard price has gone up with the demand.

Now I have been around for a while and I do all my own work, I have a 97 4 door 5.0L awd 8.8 31 spline disc braked 3.73 limited slip under my 88 BII. This required cutting off all the explorer style mounts, traction bars, etc. I then coverted the axle to spring over to match the BII leaf spacing and adjusted the pinion angle. I also had to fabricate a BII style sway bar using part from the Explorer, the BII and a Ranger. I also had to weld on BII style shock mounts.
I have since replaced the parking brake assembly, the ring and pinion, had the limited slip rebuilt for more grip, eliminated the stator ring for the ABS brakes, replaced the rotors, calipers, and pads, amongst other things.

Going to 4.10 will be a nice upgrade for you but if you plan to run 33" tires, chances are you will go bigger soon after so the 4.56 or 4.33 (2wd only) would be a better choice. These ratios were not available form the factory.

Ring and pinion gears along with install kits are cheap and labor is reasonable. Again I believe this is a much easier route then swapping out the entire rear axle. It is also cheaper in most cases.

 

[410Fortune]

Choosing between 4.10 and 4.56 can be difficult.
Alot of it is truck use, transmission type, engine type, and tire size.

I currently run 4.10 ratio with a hopped up 4.0L and a custom A4LD automatic. It scoots along just fine and is right where it should be on the highway, but I could get away with 4.56 and it would make it that much easier to go 35" tires.

A 5 speed tranny can get away with 4.10s where and auto might need 4.56...it just depends.
I stuck with 4.10's because I do alot of long distance driving to the trails and across country and I swore I would never need larger than 33's, well lately my 33's look pretty small compared to these other big dawgs!
I think 33's and 4.33 would be PERFECT, but they dont make 4.33 for the front diff, 2wd guys can also get 4.88

 

[GooseR]

Choosing between 4.10 and 4.56 can be difficult.
Alot of it is truck use, transmission type, engine type, and tire size.

I currently run 4.10 ratio with a hopped up 4.0L and a custom A4LD automatic. It scoots along just fine and is right where it should be on the highway, but I could get away with 4.56 and it would make it that much easier to go 35" tires.

A 5 speed tranny can get away with 4.10s where and auto might need 4.56...it just depends.
I stuck with 4.10's because I do alot of long distance driving to the trails and across country and I swore I would never need larger than 33's, well lately my 33's look pretty small compared to these other big dawgs!
I think 33's and 4.33 would be PERFECT, but they dont make 4.33 for the front diff, 2wd guys can also get 4.88

See, the Junkyard that i go to isnt like the normal walk in you find it they pull up a number in their head. this place you pay a dollar to get in, they say they dont inventory their cars(BS, just so you pay the dollar). But they have a set price for EVerything. Engines are 100 bucks.. muffler is 6 bucks... bumpers are 20 bucks. etc etc.... I guess its good, lol.. I dont remember what year explorer they had there but i know they had one with pretty much everything except the seats.. maybe ill go tomorrow on my lunch break and check to see if it has 4.10.
Couldnt i use parts off my current axle to better the other one(brake lines etc)??
If i get the 4.33, how much would that be for just the gears? (yes, i have 2wd)
Then, how much for everything else except installation, you said something about a master install kit. and does it actually come with everything you need to install it... b.c my dad used to be a mechanic and my nextdoor neighbor is currently a mechanic?
And what is a BII?

sorry for all the questions, i just like to hear what other people have to say b.c they have had their X most likely a hell of a lot longer than me...lol

 

[GooseR]

so could i get http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33731&item=2473136446&rd=1 or
http://store.summitracing.com/partdetail.asp?part=RMG-6903761 (if i go with 4.33 gears)

and

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33731&item=2473132362&rd=1

and install it ok w/o problems?