Swapping out at 3.9 and putting in a 3.73? I suppose it's possible but would be highly unlikely. Not sure what the benefit would be if someone did that, unless it was done accidentally.

Meh. I have had multiple trucks with the stock "small" brakes and 35" tires, it's not the huge difference that people make it out to be. Difference in pad engagement is something like an extra quarter inch. Never had a problem stopping my 4runner weighing in at 4200 lbs and a 90 lb wheel and tire on each corner.

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I just picked up an '02 V6 4WD SR5 for $1,500. Rear diff is howling. Looking at options and I'm already getting confused and conflicting information on gear ratios. The stock tire size is a 225/75-15, on the door sticker. The axle code is A02A. After Googling and reading a crap ton of posts, it's steering me to think the ratio is 3.90. But then I asked for a quote from Just Differentials/Nitro and they responded that I have 3.73 gears. And then a few posts up I see another person with the same year/engine/drive/trim is reporting a 3.73. Looks like I need to do the tire spin and driveshaft count thing to be sure.

The door sticker on almost all 3rd gen 4Runners says the tire size is 225/75-15. There is a good chance your truck is actually a 16" wheel truck despite the door sticker. I say that because my 4Runner actually was a 2WD 15" wheel truck and has an A01A axle code, verified to be 3.73's.

I expect you have a 16" wheel truck and 3.90 gears - do the spin test to verify.

-Charlie

They're definitely 15" wheels because I just looked at the tires and replaced the spare on it that was 18 years old. The original Firestone spare was a 225/75-15. the PO put some Michelin LTX M/S 235/75-15 on it. Only a 2% size difference so I'm not too worried about changing the gear ratio.

I live at 7,000 ft elevation in the mountains east of Albuquerque, NM and needed something with 4WD for my son to get to/from school at University of NM, on the other side of the mountain, in town. So it's just for paved road use. I've got a '99 Land Cruiser for the off-road stuff. I don't plan to change the tires or the gearing. Just need to replace/repair the rear diff so it will stop howling and wanted to attempt to figure out the ratio without having to pull it out and count teeth.

Tires and door sticker.

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That should coincide with a 3.91 ratio.

Sorry to break in but on a similar subject, did any of these trucks have a positrack rear end? Now that I have disabled my abs that would be a mod I would consider for my 2wd.

I don't think any 4runner came with LSD. Only option was a center locking Atrac or rear locker. Some Rav4 models have auto lsd.

This may help you in your quest for a limited slip differential.

are their limited slips available for a 3rd gen 4x4

You may have to go the route of Detroit Truetrac differential if you want to have limited slip. :-(