Wonder if you guys can help me out? I have a 65 442 which I'm presently changing the diff. lube. do you guy's put the lube in with the axcel hanging or it being level? The lube filler hole is in front of the axel tubes and below.With the diff. being level alI I could get in (lube) is a little less than a quart and a half befor dripping out. If the axcel was hanging much more could go in. what do you guy's think? Guy

 

I prefer it being level and fill it so that when I put my index finger through the hole and bent at the first digit, I can feel the gear lube. Running out of the hole is over filled.

 

It's also a self correcting problem. The fill hole is put at the height it is for a reason.

 

If you have an Anti-Spin (Posi) differential, don't forget to put in the limited slip friction modifier additive before filling to the hole, unless the gear oil you're using already has the friction modifier in it.

 

It’s a ‘65 so there’s a possibility a posi could be a cone style, which doesn’t need the limited slip additive.

 

Thank you Gentlemen. I kinda knew about the lube level at the fill plug but wasn't sure about the axle position. my car on my lift in my garage has a slight angle due to the pitch of the floor. It will be ever so slightly over filled but should do no harm. A little less than a quart and a half sure didn't seem like a lot hence the ask! I used Penn Grade 80-90 G5 lube which is for anti slip Diff. Thank you again for your help. Guy

 

Fill the rear till the FLUID RUNS OUT OF THE FILL HOLE... That is proper. anything less you always risk shorting the rear of lubrication.
When the rear is running that fluid climbs the gear and get thrown to the pinion upper hole to oil the pinion bearings. oil get thinner the hotter it gets so that fluid will fall off quicker and lube less. ALWAYS put the fluid to the FILL level... dribbling out.
With 1970 and newer rears this level is EVEN MORE CRITICAL!!! as the axle bearings need the oil to lubricate and the only way they get oil is in heavier turns....Just look at where the bottom of the fill plug is compared to the axle tube. it is at the bottom... so when you fill the rear your not even getting fluid into the axle tube sitting flat.
Good luck.
Double think your finger checking method. .... Just trying to help you all understand how this works. OIL LEVEL is critical for the rear as all it has to protect itself from heat and lubrication.
Jim
JD Race