Rear end replacement? What works?

Demi_II · Feb 6, 2014

Hey guys, if this information is here somewhere I apologize because I cant seem to find it. I have an 87 BII 4x4 and the rear end is shot. I dont trust myself to rebuild it and was wanting to buy one new. The axle code:42
open 7.5"
2640
3.45 ratio

What can I use? Can I use a ranger 7.5? I saw in the library it warned against that. What can I use to replace it and where can I buy one?

This is my only vehicle and I need to get it back on the road as quickly as possible. Thanks so much for the help.

adsm08 · Feb 6, 2014

Well, the catch with the Explorers and the BIIs is that the spring perches are in unique spots. The Explorers are under the axle, instead of over it, the BII perches are farther apart than the others.

If you want bolt-in you kinda need to find one from a BII.

4x4junkie · Feb 6, 2014

What's wrong with your current axle?

You've eliminated the driveshaft as possibly being your problem, correct? (this assuming you're still running the stock dual-CV driveshaft)

Demi_II · Feb 6, 2014

Well first it was just howling under throttle above 35 and my rear antilight brake light would come on. Today however, something inside broke and bound up. It sounded like someone was beating on it with a hammer. LOUD under load and nothing at all off throttle. Got it up in the air and spinning the wheels it would bind up. There also was a LOT of play when turning the driveshaft by hand. Like a 1/4 turn before the wheels would move. Where can I get a new or rebuilt BII rear end?

Ledphoot · Feb 6, 2014

ring and pinion from any ford 7.5 rear will fit , check your you pull it yards for mustang cougar etc "fox bodies" or your local Craigslist. You housing is special to the bronco 2 and there is no "bolt in swap" But the guts are dime a dozen.

Demi_II · Feb 6, 2014

Ledphoot said:
ring and pinion from any ford 7.5 rear will fit , check your you pull it yards for mustang cougar etc "fox bodies" or your local Craigslist. You housing is special to the bronco 2 and there is no "bolt in swap" But the guts are dime a dozen.

Im pretty nervous about doing a rebuild myself. I would love to do it, I did an engine swap myself, is the shimming and all that as daunting as it seems? There is noting wrong that I can see with the case. Are there any how-tos for complete noobs?

baddis · Feb 6, 2014

Ledphoot said:
ring and pinion from any ford 7.5 rear will fit , check your you pull it yards for mustang cougar etc "fox bodies" or your local Craigslist. You housing is special to the bronco 2 and there is no "bolt in swap" But the guts are dime a dozen.

wouldn't it still have to be set up though?

adsm08 · Feb 6, 2014

You can head to the junk yard and pull one, or you can go to a shop and have it fixed.

Those are about your only options the way I see it. Unless you are gonna take a whack at fixing it yourself.

Demi_II · Feb 6, 2014

adsm08 said:
You can head to the junk yard and pull one, or you can go to a shop and have it fixed.

Those are about your only options the way I see it. Unless you are gonna take a whack at fixing it yourself.

How scary is it? I can swap a head gasket....this seems more precise though. I have a shop that does good work for cheap. You know what they say though, if its good and cheap it aint fast.

4x4junkie · Feb 6, 2014

Demi_II said:
Well first it was just howling under throttle above 35 and my rear antilight brake light would come on. Today however, something inside broke and bound up. It sounded like someone was beating on it with a hammer. LOUD under load and nothing at all off throttle. Got it up in the air and spinning the wheels it would bind up. There also was a LOT of play when turning the driveshaft by hand. Like a 1/4 turn before the wheels would move. Where can I get a new or rebuilt BII rear end?

Yeah, that definitely sounds like the axle for sure.

If you want to take a stab at it, i would suggest reading up about setting up ring & pinion gears. Randy's Ring & Pinion has some literature that explains what all is involved pretty well. There's also plenty of other resources on the net as well. You will need a number of special tools though.
http://www.ringpinion.com/Content/HowTo/TechnicalInstructions/Yukon_Installation_Kit_Instructions.pdf

There are also some links here in the Axles FAQ about changing gears that might be useful (sites showing what gear patterns look like and how the various adjustments affect them, etc.).
http://www.therangerstation.com/forums/showthread.php?t=136954

Biggest thing is going to be making sure your axle housing is fully clean and that it's not damaged at all.

Demi_II · Feb 6, 2014

4x4junkie said:
Yeah, that definitely sounds like the axle for sure.

If you want to take a stab at it, i would suggest reading up about setting up ring & pinion gears. Randy's Ring & Pinion has some literature that explains what all is involved pretty well. There's also plenty of other resources on the net as well. You will need a number of special tools though.
http://www.ringpinion.com/Content/HowTo/TechnicalInstructions/Yukon_Installation_Kit_Instructions.pdf

There are also some links here in the Axles FAQ about changing gears that might be useful (sites showing what gear patterns look like and how the various adjustments affect them, etc.).
http://www.therangerstation.com/forums/showthread.php?t=136954

Biggest thing is going to be making sure your axle housing is fully clean and that it's not damaged at all.

Hmmm. Alright. I wanted to swap in an 8.8 at one point. does it make sense to go that route?

Ledphoot · Feb 6, 2014

an 8.8 requires welding and fab work. I've had good luck pulling the guts out of a rear and putting it into the old housing just keeping all the shims where they were. Big issue pulling one down is the pinion nut requires some serious torque. Where are you located, maybe we can help you find a complete rear.

Demi_II · Feb 7, 2014

Im near Valdosta GA. Im going to price some gears and see what I cant find.

Demi_II · Feb 7, 2014

So i recently lifted it and swapped to 31 " tires. I think i want to change the gears too. What exactly to i need to buy?

Demi_II · Feb 8, 2014

Okay Ive done a bit of reading Im just not sure what all I need. I think I will let the shop do the work because I cant afford to break anything. Im looking to overhaul the rear end and put 4.56 in front and rear. I cant seem to find a listing of exactly the parts I need to get and drop off at the shop. Any help would be very much appreciated.

Rear end replacement? What works?

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