72 differential oil/fill line?

[Siedl]

Originally Posted by dmjlambert

Hold on to your rusty one, an aftermarket one will not be as good. I took mine off when I drained it to refill with new oil. While it was off I cleaned it up and painted the outside, and stuck the bolts through a piece of cardboard and painted the bolt heads. The inside was very nice with no rust due to being constantly exposed to oil. I used a POR-15 starter kit from Amazon.com, it was quite inexpensive and the whole job just took a couple teaspoons of paint. A little goes a long way with POR15. Do not get POR15 on anything you don't want painted permanently, such as your hands. It will not come off. Make sure the lid and top lip of the paint can are perfectly clean when you re-close the can, or the lid will not come off again the next time you have a little rust-proofing project. Dip into the can with a plastic spoon and transfer the paint to a disposable container such as a pie tin, so you don't contaminate the paint. This gives you an excuse to start the job by eating pie.

You had me at “pie”. Yum
Posted via Mobile Device

[Siedl]

Originally Posted by Stocker

You have a fill hole though, right? Remove the cover to drain the diff.

I’m assuming the one threaded end sticking out with a nut on it is the fill hole...it’s definitely not a bolt that keeps the cover on so my brilliant deductive reasoning, since it’s on the top, tells me it’s a fill hole. I just need the 3/8 square to get it off...it’s around here somewhere lol.
Posted via Mobile Device

[cornerstone]

Originally Posted by dmjlambert

I used a POR-15 starter kit from Amazon.com, it was quite inexpensive and the whole job just took a couple teaspoons of paint. A little goes a long way with POR15. Do not get POR15 on anything you don't want painted permanently, such as your hands. It will not come off. Make sure the lid and top lip of the paint can are perfectly clean when you re-close the can, or the lid will not come off again the next time you have a little rust-proofing project. Dip into the can with a plastic spoon and transfer the paint to a disposable container such as a pie tin, so you don't contaminate the paint. This gives you an excuse to start the job by eating pie.

This is excellent advice about the POR-15 product. I've never needed an excuse to eat pecan pie, but it's good to have a back up plan in case my wife starts to complain about my gut.

[72c20customcamper]

Originally Posted by Siedl

I’m assuming the one threaded end sticking out with a nut on it is the fill hole...it’s definitely not a bolt that keeps the cover on so my brilliant deductive reasoning, since it’s on the top, tells me it’s a fill hole. I just need the 3/8 square to get it off...it’s around here somewhere lol.
Posted via Mobile Device

I use a 3/8 ratchet or extension no special tool needed

[Siedl]

��

[Siedl]

<insert thumbs up emoji here> Lol

[toolboxchev]

Originally Posted by fastwillie 696969

remove the drain plug first before poppin the cover off ,basic open diff. 2qts 75-90 w gear oil Quaker state or Lucas lubrication ,take a ball peen hammer and slight tap the bolt holes flat and clean off surface to prep for silicone gasket sealer ,install the cover with the rtv ,tighten the bolts 20 ftlbs ,add oil to the drain hole on the side of the rear just when it drips out put the plug in
if its posi used the synthetic oil

Be sure to let your Black RTV to cure and dry overnight before filling with gear lube.

Just a safe way to ensure it does not leak. I always use a gasket and and smear a light coat of RTV on both sides of it.

[Siedl]

So the ujoints is making a horrible clacking noise. I’ve been reading up some on this forum and some are “serviceable”. If it’s making the clacking noise can I recover from it by adding grease? Or is it too late when you hear the noise?

[Siedl]

Originally Posted by Steeveedee

Make sure that you can get the fill plug out before you drain the gear oil! If it is stripped, your truck will be immobilized until you can get it out.

A clacking noise will probably be a u-joint.

So the ujoints is making a horrible clacking noise. I’ve been reading up some on this forum and some are “serviceable”. If it’s making the clacking noise can I recover from it by adding grease? Or is it too late when you hear the noise?

[72c20customcamper]

There are a couple sealants made for gear oil . I use the Permatex right stuff it's more expensive but it's better than plain RTV . Permatex also makes one just for gear oil use

[Steeveedee]

Originally Posted by Siedl

So the ujoints is making a horrible clacking noise. I’ve been reading up some on this forum and some are “serviceable”. If it’s making the clacking noise can I recover from it by adding grease? Or is it too late when you hear the noise?

If it is a u-joint making the noise, replacement is the only solution. Serviceable means that they can be lubed with a grease gun. Too late for that, sad to say, but they are certainly cheap enough. If you have a two-piece drive shaft, replace all the u-joints and the center carrier bearing assembly all at once, to avoid crawling under your truck over and over.

[Ironangel]

Originally Posted by Siedl

So the ujoints is making a horrible clacking noise. I’ve been reading up some on this forum and some are “serviceable”. If it’s making the clacking noise can I recover from it by adding grease? Or is it too late when you hear the noise?

I have read through this thread and nearly got dazed and confused myself..."Siedl" there is a fill plug located on the front right side of the differential housing. (Passenger side)about half way up. You fill the differential there with 80w-90 MP Gear Lube until the lube reaches the fill hole, install and tighten the plug. All you guys claiming that you don't need a gasket are shade tree wannabes living on borrowed time! The Felpro RDS-13391 is the gasket for the Truck-12 bolt differential. Use it with a thin film of your favorite oil resistant silicon applied to both sides and your golden. Take a look at the bolt flange of the cover and flatten out any dimples or high spots with a small ball peen hammer. 5/16 bolt only gets 12 ft lbs of torque,