I have 1986 D250, since it's a 3/4 ton I am thinking it may have a Dana. It's not a full floater. It has the 318/727 and I'm wondering if someone can tell me what these usually had in them as far as the make, model and gear ratio it may have.

 

If it is not a full floating axle and is stock it is an 8-3/8", 8-3/4", or a 9-1/4". The 8-3/4" has the carrier assembly that comes out of the front of the pumpkin. There is no rear cover. The 8-3/8" has a 10 bolt cover and the 9-1/4" has a 12 bolt cover. For gear ratio there should be a tag on one of the cover bolts. If it is not there let us know and we will explain how to figure that out.

 

It has a rear cover, so it's not the 8 3/4. I will have to go out in the shop and count the bolts, but I do know there is not a tag anywhere, I have already looked. So how do I tell what ratio it has? Thank you for the help.

 

I'll bet you 5 monopoly dollars it is a 9.25.

 

Yep, it's a 9-1/4. Now how can I figure out the ratio? Is the 9-1/4 a good rearend?

 

Jack up one rear wheel with the trans in neutral and the e-brake off. Use chalk to mark the bottom of the tire and the yoke on the rear where the driveshaft attaches. Rotate the tire one revolution until the tire chalk mark comes back to the same position. While you are rotating the tire count the number of times the yoke rotates. 3.5 yoke revolutions means it is a 3.55 ratio as an example. The 9-1/4 rear is a good rear but will not carry the loads of a full floating rear. You have what they consider a light 3/4 ton truck.

 

Ok thanks for the help! What ratio was the most common for this application? Do you think Dodge dealer would be able to look up a vin this old to find out more info?

 

Well, I marked the tire and yoke then turned the tire one revolution slowly, the yoke only turned 1.75 times. I did it twice with the same results, seems a little weird doesn't it?

 

Did you jack up one wheel or both? Is this a positraction rear?

 

I jacked up both wheels, no it's not a posi traction rear. Should I have only jacked up one wheel?