I am installing a 3vz in my originally equipped 4cyl truck. Should I use the rear 3rd member from the donor 4runner? I know they fit, or will the 4cyl diff be alright? Also, any links to a page I saw awhile back on truck vin codes and the corresponding ratios?

 

Count the ring teeth and divide by the pinion teeth. That will give you your ratio. If they are both the same, or you are wanting the gears in the 3vz truck (perhaps they are different) then use it. They will bolt in, but the driveshaft flange might be different..

 

4-cyl diff will probably be fine, the V6 diff is a little stronger. Several ways to determine gear ratios below (including a link to the VIN plate decoder):
http://www.4crawler.com/4x4/4R_TechI...oDetermination

 

Not sure why you went to a 3.0 as the power to weight ratio with the 22re is better and the 3.0 is a weak motor but to the question about rear ends... What do you have right now as far as truck or 4runner year wise? The V6 third is a bit stronger but your doubtfully going to break the 4cyl. 3rd with the 3.0 so I personally see no reason really to hassle with installing the V6 one. If anything I would keep the 4runner V6 3rd as a spare if you wheel or think you could possibly break the stock one you already have in there. Just IMO

 

I would get the ones from the v6 truck. They are more likely to be either 4.56's or maybe even 4.88's from the factory. Your 4cyl truck is probably only 4.10. I would definitely do this you you have larger than stock tires.

 

I found a site and looked up the gears, since the donor 4runner is a 2wd, the rear diff is a 3.90 2 pinion type with no limited slip...so I am hanging on to the one I have in my truck.