1990 axle 2wd vs a 1989 4wd rear axle ????

[treeguy]

The 2 trucks in question are both extended cabs & 5-speeds & 2.9L. The '90 is 2WD & the '89 is 4WD. The rear tag on the '89 says its 3.73 gearing, what is the likelihood of the 2WD '90 rear being the same (the rear tag is gone) ??? I am swapping the 4WD ('89)stuff into & underneath the 2WD ('90) and am wanting to save 2WD rear-end if at all possible. Any input would be appreciated. If I have to I can pull the rear cover & count teeth, but I am not sure which ones I need to pay attention too . . . any pics out there that would be helpful. Thanks in advance !

 

[merace19]

count the big gear teeth and then the small pinion teeth. Pinion is what drives the ring gear. then divide. My ring gear had the ratio stamped on it.

 

[treeguy]

I will pull it off today & see what number is there . . .thanks.