Looking for advice on these differential bearing caps

These cracks don't look right to me. Do I need new caps?



Here is the other side. This can't be normal. Only 53K miles (as far as I know) on this differential.

Thanks for any advice or input from those that know and have experience working on differentials.

[tccrab]

If they're just casting marks I wouldn't be too concerned.
If they're cracks I'd think seriously about replacing them.

Has this diff ever been out of the car before?

TomC
'Crabs

[carter200]

Craig,
Have the machine shop magnaflux the caps to be sure the "cracks" aren't an issue.

Originally Posted by tccrab

If they're just casting marks I wouldn't be too concerned.
If they're cracks I'd think seriously about replacing them.

Has this diff ever been out of the car before?

TomC
'Crabs

Thanks Tom, these concern me and don't look like casting marks but hoping some of the folks that just did there might be able to chime in. As far as I could tell, it seemed like the first time out of the car based on all the bolts and condition of the other items like the half shaft ujoints, etc. They were almost one with the yokes.

Originally Posted by carter200

Craig,
Have the machine shop magnaflux the caps to be sure the "cracks" aren't an issue.

Carter,

Thanks, good idea and I do have to go there to take all my bottom half stuff next week when I get the shipment. They look pretty wicked and I'll look into new ones just in case.

[Jagdpanzer]

Given that the caps are obviously of none ferromagnetic material I'm afraid you will find magnafluxing ineffective. Dye penetrant inspection would be the more appropriate method. I've been through a few C4 Dana 44s and have to agree with Crabs, what you are looking at are marks left over from the casting process. A little rubbing with 400 grit should make them go away. If not then you really do have a crack.

[flyin ryan]

Originally Posted by Jagdpanzer

Given that the caps are obviously of none ferromagnetic material I'm afraid you will find magnafluxing ineffective. Dye penetrant inspection would be the more appropriate method.

Exactly right...What you need to do is often refered to as 'Zyglo'.

[GOLDCYLON]

Wow those look like cracks to me. Thanks Ryan and JP I had no idea how you would inspect these beyond magna fluxing. I would ask JVD hes seen a few rear teardowns before

Thanks for the advice and I'll try it out. How hard is it to find the dye? I'll check around. Worst case scenario I found these, but a little pricey:

http://cgi.ebay.com/ebaymotors/1985-...item5ad4895c8b

Originally Posted by Jagdpanzer

Given that the caps are obviously of none ferromagnetic material I'm afraid you will find magnafluxing ineffective. Dye penetrant inspection would be the more appropriate method. I've been through a few C4 Dana 44s and have to agree with Crabs, what you are looking at are marks left over from the casting process. A little rubbing with 400 grit should make them go away. If not then you really do have a crack.

So the caps looked like this on all the ones that you worked on? These really look like cracks and I'll go in the garage now to check it and hit it with some 400 grit as suggested.