Just wondering what gear ratios came stock in 79 broncos.
My 9" has some sort of a limited slip type locker in it, guessing from the factory?
And it's got a dana 44 up front.

 

The trac-loc LS was a factory unit. The most common ratio was 3.50:1 with an optional 4.11:1 for certain. There may have been "shorter" ratios available in the F-series at the time.

 

Is there any way to figure out what ratio without taking the rear chunk out? I've never removed one from a 9" before.. I imagine it's not extremely difficult.

 

With any luck it may still have the aluminum tag on one of the rear end bolts. That will have all the rear ratio info.

 

Look at the tag on the driver's door it should have an axle code on it, post up and let us know what you find. My 79 Bronco had 3.50s open diffs ft and rear, now it has 4.88s with a Power Lock in the front and a full spool in the rear.

 

My gallery has a picture of what the tag should look like. Should be bolted to the cover, lower passenger side.

 

First number on the lower row is a 3 as in 3.55, that's the axle ratio, it's been worn down so that the 3 doesn't show up.

The 8M16 is the build date, the number on the top row is the version number.

The 8.8 is the size.

yes I did put it back on the axle, now the axle was replaced by the PO because he broke the orginal one. Replacement is off of a 89 Truck

 

No axles tags. And the tag that was riveted into the door had these codes that didn't really seem like axle codes. The first row- U15HLED7016. The second row is the VIN- 104H0150AT1GH2. I don't know if that's helpful. And the last row(bottom row) has 06100, 1979 28 on it. Don't know it this is helpful but thanks anyways.

 

to get a close idea you can jack up the rear mark the pinion yoke and turn the tire one revolution and count how many times the pinion turns.

 

I can try that tomorrow, how would I know though? Say the tire turns one time and the yolk turns three(just an example), what ratio would that be?

 

Driveline turns once, wheel turns once 1.00 ratio

Driveline turns twice wheel turns once 2.00 ratio

Driveline turns thrice wheel turns once 3.00 ratio.

It's similar from there on. and in between.

 

So if it turns three and a half times it'd be 3.55 ratio? Sounds simple enough. I'll probably end up the takin the chunk out anyways. It could use a new gasket.

 

Your axle code is H2, according to my chart that comes out as a 3.50 ratio with limited slip.

 

It is fairly straight forward. Both axles have to come out a bit then take the third member out. It is somewhat heavy. Just have some rags or small pails ready (gear oil) and some RTV siicone and more gear oil.

 

I figured out from my new bronco graveyard catalog that my running gear has 3.50 gears in it, which I think is alright for the 35's I plan to put on it.