There is a LINE on your factory cover for the proper fill level. If you fill until it comes out the hole, that is too much fluid. the AMM axle is very sensitive to over and under filling from what I hear. Fill it to the FACTORY fill line that is printed on the differential cover itself!

 

This may be an extremely dumb question because I have not done this job on my truck yet, but if the line is on the inside of the cover how would you see the line once the cover is back on for refilling? The fill hole is in the cover itself and very small correct?

 

The line is of course on the OUTSIDE of the cover.. I believe it even says FILL LINE...LOLOLOLOL After the cover is reinstalled, fill with 4 qts and put your pinky finger in the fill hole and see if it is at the level printed on the outside.. I will go take a picture of the cover.. post again in a minute..

 

OK, here is the picture I just took of the cover off of my 07... It is about 1/4" below the fill hole. I also included what I replaced my factory cover with.... the day it rolled off the lot.....

 

It's hard to read on this picture but it says "Fill Line" to the left and center of the fill hole...

 

It looks like it is below the bottom edge of the hole and I believe that reflects the level the service manual specifies.

 

It's not easy to see from the picture, but if you look at it up close it is down there a little ways..

 

Rear diff is 3.825 qt from the Dodge service book.
Last 3 times I filled it it was about that just to the fill hole.

Front diff is 2.375 qts.

 

Thanks for clearing that up for me. The cover on my truck isn't as clean as yours which is why I probably never spotted it. Is that plug on the side of your new PML cover the full indicator? When I change my diff fluid I will probably get a nice aftermarket one as well. Thanks again for clearing that up for me, and the pics.

 

Thats something that they just started doing in the last few years, did not see it on the 03-05's that I remember but dads 06 has it.

 

That may explain why I can't see it on my '04

 

Just open your eyes...... But it helps if its there in the first place......
If you just use the fill plug then you will be fine or just shoot for 3.8 to 4 qts....

 

Nope, they started putting the fill line on the 2003's and up. My 2004 sure had one on it too!! It was actually a 2004.5 600 but it had it on there. I have three covers in my garage. 2004.5, 2006, 2007. ALl are Identical!

The side hole on the PML cover is for the fill line yes, and it is at the same level as the factory line. The top plug is the fill hole. The PML adds one quart capacity so I add 5 quarts total! PML cover is far cheaper than the Mag Hytec.

 

Thanks for all the info guys. I definetly like the PML covers, I've already been pricing them out today.

 

My early 03 doesn't have the fill line, and the dealer told me not to fill to the bottom of the plug as they were apparently revising the proper fluid level to avoid blowing seals.

Shortly after that they started coming with a fill line stamped below the bottom of the hole.

There was a big long thread about it back then...