I'm trying to figure out what kind of rear diff is in my 1997 5sp 4x4 4Runner (VIN JT3HN86R2V0115381, Frame VZN185L-GKMGKA) and what ratio it is. The axle code on my data label is A02A. The consensus of axle codes I've looked at says it's a 2-pinion, 3.58:1, open diff. I did a spin test and came up with 3.9:1. Top attached picture my diff, next picture is LC Engineering's pictures of various Toyota 4Runner/T100 diffs. My diff seems different than all of those. The ratio on mine HAS to be 3.9:1, but what else can anyone tell me about it? Thanks.

 

PS: this is the best article I've found so far on 3G T4R diffs: https://lcengineering.com/differential-information/

 

A02a is 3.9, you can call or email ECGS and they will help and supply the 3rd member for that code, once you take it out the ratio is stamped on the ring gear. Now if the data label says your truck came with 15rims and smaller tires that might explain it and it probably has 3.91 ratio, again ECGS will know what you need. 15'" rim trucks also came with smaller brakes and smaller wheel cylinders.

 

Good advice about ECGS, I'll check it out.
Attached is the pdf I used for finding my Opening Post axle code. I goofed and skipped a line when I was reading that pdf and wrote 3.583 instead of 3.727 for A02A in my Opening Post. You also had 3.727 in your initial post reply, which seems correct per my pdf. Then you edited it to 3.9 for A02A. I've seen quite a few threads that say the door jamb A/TM (Axle/Transmission) codes are highly unreliable. What was your source for calling A02A a 3.9 ratio? I'm not badgering, I'm hoping there is a reliable 3G T4R V6 Axle Code Chart out there somewhere. I've heard Sonoran Steel used to have a good one (along with other good stuff), but that information isn't accessible on their website any more--at least when I try. I'd also like to know if I indeed only have 2 pinions and a 7.5" ring gear per my pdf--which makes it a pretty weak-a$$ diff if true...

 

If you read the taco charts part of your code indicates 3.737, but for the 4wd 4R it is suppose to be 3.91 for a02a, and they are easy to mix up and why everyone says to do the spin test to confirm or look at the stamp on the ring gear if it still factory original. I thought all 4R's have a 8" rear and 7.5" front diff, and both are 2 pinion open diff, but again email ECGS your info and get a quote.

 

Thanks for your help.