Is this common? I thought all Bronco's had a LS. Here's the tag from my rear diff. I was surprised to not see L between 3 55. So now I'm thinking of converting it to Limited Slip. Maybe not as easy as adding the appropriate clutch packs but will research.

 

Can you see the code on the door frame VIN decal?

 

No, not all Broncos had a LS. In fact, I'd say most of them did NOT have one. Adding one involves swapping out the whole carrier and setting up the gears (backlash, preload, etc). Consider changing the gear ratio while you're at it. 3.55s are terrible in these Broncos IMO.

 

Limited Slip was actually quite rare.

 

LS (Limited Slip) was an extra cost option.

1959 thru today:

If the AXLE code stamped on the Rating/Warranty Plate (1959/79) or printed on the Certification Label (1980 thru today):

Begins with a letter: Limited Slip.

Begins with a number: No Limited Slip.

And be aware that the 3rd digit of the AXLE code refers to the front axle, but some 1959/79's may not have a 3rd digit, most 1980 and later don't have it.

The most common 3rd digit for 1973/79's is J = Power Steering.

 

I thought the letter came between the two numbers. Like "3L55" vs "3 55".

I've never seen them begin with a letter.

 

Read my post again, because...

I was referring to the AXLE code stamped on the Rating/Warranty Plate or printed on the Certification Label.

1978/79 Bronco example H2A: H2 = Ford 9" rear axle / 3.50-1 / Limited Slip / 3,750 lbs. capacity // A = Adjustable Steering Column with P/S

 

Oh oh, I gotcha.

 

Post #7: I edited in an example of a 1978/79 Bronco AXLE code.

3.55-1 found in 8.8's, not available in 9."

8.8" introduced in 1983 F100/150, Bronco & E100/150 (Econoline), but the 9" was still available thru 1986 F150/Bronco, thru 1987 E150.

 

Thank you all! Now I know. I was thinking of changing to 3.73 or even 4.10. Though I'm leaning toward 3.73. I've put on tires 1.6" larger in diameter and have learned that the 3.55 ratio is just not cutting it.

 

1.6" taller.
I'm guessing you went from something like a 235 75R15s to 265 75R15s? (~29" to ~30.6")?

A couple things to think about.

Gear upgrades can be expensive.
You probably won't notice too much by going from a 3.55 to a 3.73. It's a pretty small change. (About 5%).
Your tire size increased by about 5%, but they're also now a bit heavier. I went from 31" tires to 32" tires and I think it was around 7 lbs a tire, and rotational mass is what gets you.
4.10s may be more the way to go.

Another thought is your money may be better spent in some engine power upgrades.

 

I have the stock 31" tires and I'm regearing to 4.10s.

 

I was doing the math over the weekend and thinking about which direction to go. Since its not my main vehicle and I want better off road performance I am going to 4.10s. I think this is the better move. I've heard people still get pretty good MPGs on the highway with OD and off road performance was great.

I bought the Bronco with 265 75R16s. I know the stock is 235 75R15s but stayed with the 265 75R16s because of the tires I wanted. Goodyear Wrangler Duratracs with the extra load rating for thicker sidewalls.

 

Definitely go 4.10 with the 5.0.