I have a '90 4Runner, with 31" tires, a sun roof, a trailer hitch, auto tranny, with the spare tire winch runner to the center of the bumper.

According to this thread that means I should have a 4.88 gear ratio.

I got the codes from my car though to double check, but I'm having trouble interpreting this spreadsheet

Anybody else want to give it a shot?

The codes are C/TR 6J7/HH11 and A/TM G294/A340H

 

Also, my title bolding didn't work. Oh well.

 

You try using the Gear spreadsheet with your Vin #? Part of the deciphering uses your Vin #

 

G294 is:

G=8.0"
29=4.10
4=4 Pinion (V6)

 

Ah thanks. That makes sense...Shoot...I was hoping it was 4.55 because I'd like to put 33's on it, but I don't want it to have even worse power than it does now. I guess all that stuff about the "sport" package was wrong.

Maybe it was a 5 instead of a 9 and I just read it wrong haha...

 

if your going to run big tires 33+ and are going through the trouble of changing ring and pinion sets why not run 5.29s (37x7)?

 

Well anything over 35s with ifs is begging for trouble. Maybe with an H1's ifs setup, but not a yota.

5.29s are great with 37s (what I'm gonna be running on mine after I finish my lift this weekend), but you should definitely do a sas if you wanna run big meats.

 

See I don't know if I actually want to do a gear change though. It apparently would only cost about $200 for the ring & pinion sets but I kind of doubt my ability to do it, since all I've heard about that it how crazy technical it is.

I have been looking at total differentials though...Plus, I'm not gonna be totally convinced mine didn't come with 4.55 (since it has 31 inch tires) until I get a chance to spin a tire and watch the drive shaft.

 

I'm really just looking at 33's..4.88 would be best for that right? Or 5.29?

 

Jack up your rear tires so you can spin them with the tranny in neutral. Count the revolutions of the drive shaft per one rev of the tire. That trick works pretty well. I'm surprised nobody has recommended it to you yet.

You posted before I finished this one. If your truck came factory with the auto tranny and 31s, you've already got 4.88s. You might consider 5.29s to run 33s.

 

$140-190 for gears (per), gear setup kit $100 (per), and labor will generally run you about $150 (per) if you don't do it yourself. Plus you'll want lockers, and that'll be an extra $180-500+ (per).

 

Doesn't lockers open up a whole 'nother can of worms with shattered CV joints from the stress though?

You know, if I do have 4.88's I bet I could sell them to someone on here too...Provided they're in good shape

 

Actually, some say having a front locker will save you from snapping cv joints. With an open diff you are liable to get a lifted tire spinning pretty good, then when it comes back down the sudden stopping will break a cv.

 

Huh...That makes sense...What about lockers on both diffs?

 

A more accurate way is to jack up one wheel, spin it around 20 times, and divide the number of driveshaft revolutions by 10. This will give you an average, because sometimes it can be hard to determine whether the driveshaft turned 4.3 vs 4.5 vs 4.8 times, and it will throw your estimations off if you turn the wheel a few inches past center. This way allows more margin for error, and will still give you an accurate count.

So you spin the wheel 20 times, you get 41 turns, you have 4.10/11 gears. It turns 45.5 times, you have 4.55/56 gears.

Or you can pull the diff out and count the pinion gear and ring gear teeth.

 

I went with junkyard 4.88's several years ago when I had IFS. I'm still running 4.88 after the SAS. Here's a breakdown of what I paid - best of all it's all bolt on and you can do it yourself.

$100 - 4.88 ADD front diff (Converted to non-add with current diff)
$125 - 4.88 V6 Rear
$120 - Shipping for both diffs (Could be worse i guess)
$16 - 2 Front Seals / 2 rear axle seals
$50 - 5 quarts of Mobil 1 Synthetic Gear oil
$4 - RTV gasket maker
$415 - TOTAL COST TO RE-GEAR.

 

Well I run 5.29s with 33s and i enjoy the pickup i get also if you wanna know your diff ratio the hard way pull the third member and look at the stamp on the ring gear (if you were gonna take them out anyway) and yeah ring and pinion work takes special tools bearing pressing blah blah blah.You can take both your members out of your truck and take them down to your gear shop thats about the cheapest way short of actually doing it all yourself.

 

I have access to an auto shop that charges something like $5 a day to use all their tools...Think they'd have all the stuff to get it done?