Bronco II Limited Slip

What would it take to get limited slip in my 7.5 rear end? Would I need to replace the entire rear axle? Or would it be possible to replace just the differential in my existing axle? Also, how would I make sure that my front and rear gear ratios match?
Thanks for the help.

I also wonder how much practical difference a limited slip differential would make and should it be done both front and rear.

I don't know if my prior BIIs had limited slip or not. My original 88 I am guessing it didn't as it was a pretty much base model though it was an XLT. My 89 could have but it didn't really handle any differently in the snow. I know the 87 I have now doesn't have limited slip (unless prior owner added) and it is an XL.

The only thing on the 87 that seems to set this one a bit different from the others is a slight tendency to fishtail when I have 4WD engaged and I hit the gas hard in the snow spinning all four wheels. My prior ones I thought tended to be more stable and drive sideways more than fishtail, but then again I may just be putting too much steering input.

I had suspected at one point that 4WD wasn't engaging, but I've done a bunch of work and have verified all four wheels do spin when I do that.

If you have the original rear end, the door sticker code will tell you what you have.
42=3.45
44=3.73
D4=3.73 traction lock
D7=4.10 traction lock
The only way to know for sure is to open it up and count the teeth on the ring and pinion.

So I'm gonna ask:

What does a standard "42" rear end have? Open or limited slip?

3.45 is what mine is...

tidmarshsmiths5 said:

So I'm gonna ask:

What does a standard "42" rear end have? Open or limited slip?

3.45 is what mine is...

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Open

I'm not sure if there's anything out there anymore for the 7.5" axle everyone seems to think swapping axles was such a great idea, that it left no aftermarket support for the OEM equipment on many of these RBV's. If you do in fact find a limited slip rear differential you can just replace the differential, however you have to be 100% sure that it has the same gear ratio by checking out the differential tag or the door tag to make sure. So if your RBV has a 3.73 gear ratio the replacement differential needs to be the same as well or you'll have some serious 4WD binding issues, speedometer will be off, etc. I'm sure at some point someone made a limited slip differential for the 7.5" axle, but I doubt there are any out there anymore due to the lack of demand for that axle.

The easy way is get the factory rear end off any ranger/B2/RBV.
Frankly I find the track lok aggressive enough in my B2 and have not found the need to tamper with the clutch pack.
And yes if you plan on using 4wd, make sure your current front diff has the same ratios as the new rear.

I live in northern Oregon along the coast mountains. Much rain and mud. I do use the 4x4 when I'm back in the hills hunting or camping.
I have some pretty sweet 30" mud tires on it now, so it gets traction. But, who doesn't want more traction?
I'll keep an eye out for a limited slip when I scour the junk yards. Mostly, I just want to be able to go anywhere.
Thanks!

TillamookB2 said:

I live in northern Oregon along the coast mountains. Much rain and mud. I do use the 4x4 when I'm back in the hills hunting or camping.
I have some pretty sweet 30" mud tires on it now, so it gets traction. But, who doesn't want more traction?
I'll keep an eye out for a limited slip when I scour the junk yards. Mostly, I just want to be able to go anywhere.
Thanks!

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Well even with a limited slip or even a locker for that matter, you still can't just go anywhere LOL. However, even a limited slip will keep you moving where a conventional open diff may leave you stuck if you aren't careful. Throw some chains on all 4 wheels in 4x4 and you'll have a completely different rig without needing a limited slip differential LOL.

These older RBV's are getting hard to grab parts for, I just wish I could have drug home the 1987 Bronco 2 I found last trip to the Pick A Part. Other than I'm guessing a serious engine or transmission failure the rest of the rig was in mint condition interior and exterior.

Since my rear axle is on its way out anyway, I recently installed a Lincoln Locker . This works pretty well, since all of the roads in Iowa seem to be straight. It chirps and scrubs the rear wheels when turning as expected, but the traction difference is huge compared to when it was open. When I do my 8.8 install I'm not going to weld it, but this experience has me strongly considering a full spool. My BII lives on gravel roads and straight highways, and rarely gets to town so this works for me. In fact I kind of like the chirping when turning around parking lots and stuff because I am a giant child.

wildbill23c said:

I'm not sure if there's anything out there anymore for the 7.5" axle everyone seems to think swapping axles was such a great idea, that it left no aftermarket support for the OEM equipment on many of these RBV's.

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The parts are out there, you just have to know where and how to look.

The key is to not look for Ranger parts, you need to look for Mustang parts. While the axle assembly as a whole is different the guts are shared between Mustang and Ranger.

adsm08 said:

The parts are out there, you just have to know where and how to look.

The key is to not look for Ranger parts, you need to look for Mustang parts. While the axle assembly as a whole is different the guts are shared between Mustang and Ranger.

Click to expand...

Excellent info as always. But if you look at Mustang parts don't you also need the 302 .

wildbill23c said:

Well even with a limited slip or even a locker for that matter, you still can't just go anywhere LOL. However, even a limited slip will keep you moving where a conventional open diff may leave you stuck if you aren't careful. Throw some chains on all 4 wheels in 4x4 and you'll have a completely different rig without needing a limited slip differential LOL.

These older RBV's are getting hard to grab parts for, I just wish I could have drug home the 1987 Bronco 2 I found last trip to the Pick A Part. Other than I'm guessing a serious engine or transmission failure the rest of the rig was in mint condition interior and exterior.

Click to expand...

Well, I know I can't go literally anywhere. I'm just talking about reducing the frequency of one wheel spinning and the other doing nothing. I had chains on all four when we had a wicked snow storm a few years ago and the Bronco was nearly unstoppable. My only issue with it is that I go on and off the pavement and I don't want to get out and chain up all the time. It would be alright to chain up occasionally. I'm after the convenience. Hooray for what works, but it would be stupid to not improve on something that needs to be done so often.

TillamookB2 said:

Well, I know I can't go literally anywhere. I'm just talking about reducing the frequency of one wheel spinning and the other doing nothing. I had chains on all four when we had a wicked snow storm a few years ago and the Bronco was nearly unstoppable. My only issue with it is that I go on and off the pavement and I don't want to get out and chain up all the time. It would be alright to chain up occasionally. I'm after the convenience. Hooray for what works, but it would be stupid to not improve on something that needs to be done so often.

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I figured you were speaking in general just thought I'd point it out LOL. I completely agree with your thought process. My 84 Ranger 4x2 was awesome in snow/ice, and I threw a set of chains on one fall to go up hunting as the road was extremely muddy. I had some pretty interesting looks from all the hunters up there in their lifted 4x4's. I was asked several times by several people how did you get that truck up here. I just said I followed you guys up the same trail you were having problems getting up in 4WD. I noticed the next year many of them were just running tire chains. However, yes, transitioning from trail to road repeatedly gets very old chaining up and pulling them off all the time. Chaining up is only really useful if you plan on having them on for a long period of time, otherwise they can become a burden.

I don't have chains for my B2, but I don't venture very far from the house anymore, and if I look outside and find a need to chain up my 4WD I'm staying home .

The snowstorm we had was the kind where it snows, melts a bit, freezes, and repeats several times. It was 10 inches or so of nearly solid ice. The ruts in the main roads were deep enough that many smaller cars simply high centered. I had the tire chains on all four wheels for about a week and a half. They were cable-type chains. Not the best, but they served their purpose well. After taking them off, there were indentations in the tire walls where the chains were. They never flattened out and were visible until I trashed them and bought Nexen Radial Mud Terrain tires last year. A couple weeks after buying the tires, my 2.9 died. Now, I'm working on a 4.0 swap. Got the 2.9 out and the 4.0 is on the engine stand for cleaning and gaskets. It should be cool.