Diff ratios
 

Is there any way to tell ratios without tear down ?
I have an 89 4 runner with 5 speed and v6
And a 91 with v6 and automatic.
The diff is leaking and needs rebuilt.
But if they were the same ratio i would just swap

There is supposed to be a paint dab on the pinion flange and the color tells the gear ratio. You may have to remove the driveshaft to view it, i don't know for sure. Others can chime in.

This should work, at least if I remember correctly it is how I verified the ratio on my manual '85 PU.
https://shiftsst.com/blog/post/how-t...xle-ratio.html
Editing because it seems the web provides different ideas on how many times to turn the tire. I'd say count driveshaft revolutions for one turn of the tire, but I'm no expert. One number will make sense and be in the right range, the other one won't.
https://itstillruns.com/calculate-re...o-7588196.html

Interesting

https://cimg4.ibsrv.net/gimg/www.yot...5c432ea92.jpeg
https://cimg9.ibsrv.net/gimg/www.yot...41f8d154c.jpeg
Codes are in the door jam. This obviously only applies if the vehicle has been left stock and the tag in the door jam is still present.

Awsome info , but mine is a 91

Edit , i gotta read more closely lol

Gonna check later , see if the stickers are there

the pinions paint code is also accurate.

The above is correct.

I'll go out on a limb and say your manual has 4.11 and the auto has 4.56
If you have a factory trailer hitch (towing package) and the 31" option, you might have 4.88s

https://cimg6.ibsrv.net/gimg/www.yot...931a9663ea.jpg
Driver (automatic) matches this one with the 5 speed :-) Looks like i scored very well for 300$ :-)

The 4.56 (code G254) was stock with the V6 5-speed with 31 inch tires. The door sticker may not indicate 31" tires - they were a dealer add-on to get around some import taxes. The vehicles shipped with smaller tires and then the dealer put on the 31's. Gearing was set up at the factory for the 31's. (A lot of these vehicles had dealer installed air conditioning for the same import tax reason.)

The driver with automatic came to me with 32s on it.
It was guttless and the tires were shot anyhow.
I swapped smaller 235/75/15s on to it ;-)
Not guttless anymore lol
But hard on fuel