hey sorry this is probably answered in this forum somewhere but I can seems to find it

I have a 1990 s10 blazer 4.3 4x4 5 speed with 3.73 gears. my rear diff has a lot of rotational play, and fron diff has bad bearings. I found a guy on craigslist selling front and rear diff from a 89 auto 4x4 4.3. he is unwilling to check the gear ratio because the car is parked far away from where he lives. I dont mind changing my gear ratio but I commute 140 miles a day and plan to do the rc 2.5 lift with 31 inch tires

I am just wondering what are the possible gear ratios for this 89 auto 4x4 and what would be the best ratio as far as keeping decent power and mpg

also he is asking 400 bucks the parts have 90,000 miles do you guys think this is a deal or should I jsut get some at pick and pull for half the price

thanks everyone

 

I believe that the most likely gears are 3.42 (GU6) or 3.73 (GT4). Suposedly there are some with 3.08 (GU4) and 4.10 (GT5). AFAIK the GT5 was only on the 2wd 4 banger.

 

I'm not to familiar with the pricing and if you're getting a deal or not, but if you plan on 31" tires, then 3.73 gears would be the best for mpg's, anything lower would result in poor mpg's and less power, anything higher would give you better towing power and such but you would lose some mpg's.