Recently the front differential went out on my 2000 Blazer. I received a replacement differential from LKQ today(told them what ratio I needed but there's nothing on the paperwork saying what this differential actually is) but I want to be certain that the gear ratio is correct before installing it.

I have the Vin # from the donor vehicle- 1GCDT19W018173980.
It was a 2001 chevy s10 extended cab LS 4wd, manual transmission.

I do not have the RPO code.

And the stamped number on the side of the differential is 26054448.

My old front differential was aluminum but this replacement is iron. From what I understand, this is the best kind of front differential for these trucks.

I'm just paranoid that I'm going to install this thing and put it in 4wd and blow something up.

Does anyone know of a way of determine the gear ratio without taking apart the front differential and counting teeth?

The Vin decoder on this site says it can be either a 3.42 or a 3.73. I'm desperately hoping this Is a 3.42.

 

You could run the donor VIN# through compnine and that will give you the RPO. It will cost you $5 though...

 

Says rear axle code

GU6 AXLE,REAR,3.42 RATIO 3.42R(GU6)

I assume this means the front should match. Logically anyways..

Am I correct in assuming this?

 

That's my best guess

 

Make some kind of mark on the input and output; turn the input, count revs and count the turns the output does - divide numbers.

 

GU6 is 3:42:1 and assuming the gears haven't been changed, it is the correct differential. I agree with LannyL81, mark the input & output, count the turns, and do the math.

 

The math never lies. Thats the way I've always done it.

 

Math sucks, dentists don't have to count past 32!!

 

Shouldn't be that difficult to count the turns. You only need to be able to count up to 3.42 or 3.73 on the yoke, and 1 on the output. Sticking a half shaft in the left output will make that one easy to watch.

 

I surrender!!