probably the question is silly, but I wanted to know if all ujoints of the front and rear shafts including those of the double cardan are the same.

 

I believe they are. I did mine a couple years back...but I don't recall having to keep them separate for any reason to keep them from getting mixed up.

 

All five are the same 1310 size except, in some models with the Dana 35
and a manual transmission, the u-joint at the rear pinion could be a 1330 size.
Just remove the rear driveshaft and measure the rear u-joint if you are not sure.

Look here for the dimensions:
https://www.northerndrivetrain.com/p...I-5-1310X.html
https://www.northerndrivetrain.com/p...I-5-1330X.html

 

If you have a Dana 44 rear, there will be at least one 130 U joint, otherwise all are 1310

 

I've dana 35 in rear znd dana 30 in front

 

1310 all around then

 

the front axle shaft joints are either 5x260 or 5x297, depending whether you have abs or not (since yours is a 1990). if not, then 260.
if you do, then you want the 297 joints.
the drive shaft joints are all 1310, and i have a d44 in the rear.
but i did use a different joint in the double carden once when i rebuilt that, along with a new center ball.