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Put 99 explorer 5.0 With 86 AOD. Running 17" rims and stock 66 gears. Next step; rebuild diff. Don't wanna reduce wheel size, so looks like gear change. Not sure of stock ratio. I think 3:50. Looking for better gear size. Considering 3:73...
What is the engine rpm at hwy speed? With 30" tires my old 5.0/3.55 geared F150 ran at about 1900rpm at 70mph.
I'd expect to find something more like low 3.xx to 2.xx gears in a rig of this age.
My guess is that you already have a fairly low gear set. 3.50-3.70 is my guess. What engine was in it stock. You can look at the warranty placard. It will tell you what rear gear came stock.
Rim size doesn't matter. You need tire size (height). You can measure the height, or use a calculator like this: https://www.calculator.net/tire-size-calculator.html
Then plug the tire height number and the AOD ratios into this calculator: https://spicerparts.com/calculators/...rpm-calculator
I would plug in the OD ratio and consider how fast you want to go on the freeway at what rpm, and plug in available gear ratios and then choose one.
Then redo it using the gear ratio you chose, and the 1st gear AOD ratio, and decide if that feels like the right rpm shift point out of first gear.
Find your balance between these based on what available gear ratios get close.
Seems like I regularly hear people shooting for a high gear ratio to get low RPMs on the freeway. In general, I think that makes the car drive like a dog, and I'd rather shoot on the lower side for a snappier response.
With my granny gear, I'm essentially driving a three speed and so doing over 3000 rpms on California freeways
My truck is running a 5.0/AOD with 10.50 x 31 tires. The AOD has a 0.67 OD, I don’t really do much highway driving and often ended up in drive to keep the trans from going back and forth out of OD withe the 3.5 gears. I swapped in 4.11s and so far I’m happy with it. Planning on a 351 swap next, the 96 roller block is in the garage. If you do a lot of highway driving 3.73s would probably be better but seems hardly worth changing from 3.50 to 3.73. I think most of the V8 explorers ran 3.73 gears but not sure anymore.
