Sorry if this post is out of place or if the info I'm seeking is "stickied" somewhere, if so please excuse my ignorance and I'll have this thread deleted. I'm swapping a 9 inch from a 69 f100 into my 53 f100, the only problem is the gear ratio is around 2.92:1 from what I remember. Can I simply buy a ring and pinion set with a desirable ratio (3.50:1-3.70:1 range) and do the swap and be done with it? Or are there other parts that I need to buy/install, such as a new differential to accomodate the new ratio? Thanks for your time
Yep. If you could find a complete center section with the gears you want, it would be an hour or so swap and your done.
Ok thanks fellas, the main question is the differential? The ratio doesn't matter? I noticed that on dana's/gm 10 bolts the ratio matters for selecting a differential from looking in summit racing's catalog
On certain Dana models there is a point where after certain ratio the carrier itself has to be swapped out. If I remember correctly there is no break like that on the nine inch and as stated above, since it is a third member axle if you can find one at a junkyard you can just pull the whole third member and swap it over. If you can't find one you can always order a complete third member online already set up.
Ford uses the same carrier for all ratios, The GM's use different carriers (2 series carrier/3 series carrier/4 series carrier) and you have to buy the gears to match your carrier. But you might be able to find a low ratio ring gear & pinion already set up in the drop out at a wrecking yard out of a pickup. That should be an easy swap into your housing. Larry T
Ford used two different axle spline counts in thier 9" rearends. A 28 spline and a 31 spline axle. I believe that your 69 rearend should be a 28 spline unit. I can't remember when ford made the change and there may be some overlap in years. The bottom line is when you find the center section with the gear ratio that you want, make sure that it has the same spline count as the unit your swapping it for. Other than that the swap can completed pretty quickly/easily. Mike
Most 69 Ford truck 9 inch rears are 28 spline. But ford being ford there are a few 31 splines. The change over to 31 spline for the ford Truck 9 inch was mid 1972.
I think your talking carrier case break, like chevy 2:70 to 3:40 gear is one case and 4:10 and up ratio is another, ford 9" is one carrier the ring gear gets thicker as the ratio goes numerically up.
yup, ford 9" uses the same ring gear offset for all of them...but they had different sizes of bearings, splines, yoke length, etc to mess with us.
When I was younger in the Air Force, I used to go to the "Auto hobby shop" on Fridays. Pull-in to pull-out, I could swap my gears in under 4 hrs. I had another carrier and would swap from 3:08 to 3:73 (and pinion) to go cruise the streets for the weekend. Did this several times, but I also broke the rule of re-using the old crush sleeve. My extra carrier, years later, fell through the sheet rock in the roof of my garage, and landed on the hood of my '96 Impala SS.. So I guess it paid me back for the abuse that I had showed it, and trashed my hood..
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