What year front diff's will fit a '97?

[HeresPaco]

Hey Guys

I need to replace the front differential in my 97 Astro.

Anyone know what all other year front diffs will bolt in and work ok?
(I'm not concerned with the ratio, I have a gear set to use in any of them.)

Thanks!

[1996astro]

I believe 97 was the year GM switched from the bolt on CV half-shafts, to the spline snap in units. Depending what you have, I think the differential case is the same from 97-05. Or, if you have bolt on from 96 and older.

I am currently working on the NP231C transfer case swap, and front axle disconnect using a right axle tube from a 99 S10 blazer. See what happens. The Astro/Safari gets into you and you can't stop.

There is a great wealth of knowledge on this board. Everyone is here to help. Somebody on here will verify my info.

[LiftedAWDAstro]

Yup 1997 and newer should work. I know 97 to 2002 are the same. Why do you need to replace it? Broken case?

I have the one from my 1998 that has a set of broken 4.11's and a rebuild kit minus the crush sleeve that I would be willing to sell. You are close so we could meet half way.

[HeresPaco]

Cool, This is the kind of info I need. Thanks !!

Dean, I pm'd you a message..

[LiftedAWDAstro]

From the PM you sent it does sound like the front diff is trashed. To really diagnose it will require some troubleshooting.

Jack the front end up and spin the front tires over and see if you can feel the binding. With one front tire going one direction, the other will go backwards. This is normal. Now put 1 front tire back on the ground and try to spin the other one. It should not spin. If it does, look at the front drive shaft. It should not be spinning. If the front tire does spin, I would say the front diff is trashed. You can drain the old oil out to see if there are any metal filings or worse yet...pieces! There is a drain plug near the bottom. Collect the oil into a shallow flat pan and not into an oil container. You want to be able to inspect the oil. There will be less than 2 quarts inside.

If you don't see anything there, lets look at the rear diff. You will need to pull the cover. Again use the same pan and inspect for filings and pieces.

Let us know what you find.