I have a 2000 blazer LS 2 door 4.3 4x4...
my daily
I have a 1999 blazer LS 4 door 4.3 4x4
parts truck
I need to find out the gear ratios so I can see if I can swap the front differential...
I'm not sure about the parts truck at the moment but my daily is missing the RPO sticker from the glove box...
any help would be appreciated

 

A VIN decoder that gives all all of the RPO codes would give you the info you need, but for a fee.

Perhaps a GM dealer's part counter could give you the same info.

Finally I guess you could count the number of rotations of the rear wheel it takes to rotate the driveshaft.

 

There may be a tag on the rear axle that shows the ratio. Otherwise, do what Christine said and spin the rear tire while counting driveshaft revolutions. Remember, if you only spin one tire, you need to multiply driveshaft revolutions by two to get your ratio.

Alternatively, you can pop the cover off and read the numbers on the ring gear. That's probably faster and more accurate.

 

I looked in the glovebox of the parts truck and it too has had the rpo sticker removed... Ain't that just great... So whatever method I go with I have to do twice and with my luck as it is... I bet they don't match lol
Would the factory tire size be an indication?
The daily came w 31/10.50/15
Theparts truck 235/75/15
At least by what the door sticker says
Apparently the daily, 2 door has off-road suspension according to google since it came with the 31/10.50

 

The only Blazers that came with the 31/10.5R15 tires were the ZR2s that only came in the 2-dr version. Those are desirable rigs.

The 235/75R15 and 235/70R15 tires were stock on all others.

If I remember correctly, the ZR2s, compared to the regular Blazers, had a wider rear axle to match the wider front suspension. If I am correct, then the parts Blazer axle will be too narrow to fit the daily Blazer, irrespective of gear ratio.

If yoy measure the gear ratios of both axles and they are the same, then you might consider swapping just the gears. But then there is also if either or both have the locking rear end option which also desirable.

Since it sounds like you are wanting to keep both rigs, I'd suggest looking for one of the VIN decoder webpages. Even if it costs you $50 to get both VINs decoded to get the list of RPO codes for both, it could be a good investment.

 

I looked at the sticker on the.door.in hopes it would provide some insight but all it shows is tire and wheel info. . It shows the 31/10.50/15 as the only size option just as the parts truck shows I believe only the 235/75/15...
I don't recall anything on the title showing ZR2 but could be wrong.
Another possible down side is I have new cv axles for the daily and now it seems you say they may not fit?
the daily currently has the cv axles removed and I don't have them to compare...
I assume I can measure the diff housings?
I guess it's also possible that the door may have been exchanged since 2000...
It has 33/12.50/15's on it with i assume t-bar lift and aftermarket lift uppers and shackles in rear...
it does appear that the rear leafs have considerably more arch on the daily 2dr than the parts 4dr truck...
also the plastics cover over the front axle and steering parts from the parts truck don't match up to the bolt holes for the 2dr...
Are these other earmarks to help me correctly identify the specifics of my 2dr?
It has the fender flares as well...

 

Looks like your 2door is likely a ZR2 with those differences. That means it almost certainly has 3.73 gears in it. I thought that there was also a ZR2 stamp on the VIN tag under the hood? Can someone else confirm this? Maybe I'm misremembering.

The front diff can be swapped with a non-ZR2 with no problems as long as the gear ratio matches, HOWEVER if it's a 5 speed ZR2 it MAY have a cast-iron front diff housing. These are generally viewed to be desirable because they're stronger than the aluminium housing used on all other S-series trucks.

The front CVs, control arms, and steering components are all different from the non-ZR2 trucks and are not interchangeable.

Christine is correct that the ZR2 axle is 3 inches wider than the non-ZR2. They can be swapped, but you definitely would not want to put a non-ZR2 axle under a ZR2 truck because it would be quite a bit narrower.

 

The previous owner has tinkered with alot of stuff so and I'm not sure how many tinkering previous owners it's had....
I finally located the under hood tag... it's been painted over lol
I was able to make out some info to to include ZR2!!!
Where thats great its also a concern as all the steering components and ball joints were recently replaced with non zr parts...
I have new cv's for it but now I know they won't fit...
Looks like I may put them on the parts truck and get it up and rolling (it runs and drives, prolly actually in better shape than daily actually)...
thank all who have provided info and responses!
I really appreciate you

 

Does anyone know if the idler arm and pitman arm are interchangeable?
I put both on new but that idler has never seemed stable and have recently bought another one thats a bit more sturdy looking at least but if its not gonna work ima take it back...

 

Looking on parts websites, they do not list different numbers for the idler arm and pitman arms. They should be interchangeable.

They also don't differentiate between ZR2 and non-ZR2 for the ball joints, so those should also be interchangeable.