I got around to installing my Mag Hytec rear diff cover this morning. The drain hole provides for about 5 quarts and from what it looks like that's about what the stock level was.
"But" why does it say to install up to 7.5 to 8 quarts ???????
With 5 quarts, it just hits the dip stick about 1/4" up on it. The marks on the stick are way above there........
So whats the deal. Does it need to have more than 5 quarts or what?? And why would they put the drain hole at 5 if it needs to be higher???
Every rear end oil I ever changed in the past, you just pull the center plug and when it run's out thats when you know you got it......
Thanks for any help.

 

OK, I dug around thru a ton of threads and found some info.
Mag Hytec has 3 levels-setting's for their Diff cover.
1. The drain plug hole is the normal stock level that DC recommends.
2. The bottom mark on their dip stick puts the fluid level at the bottom of the axle tubes.
3. The mark farther up the dip stick puts the fluid level at the "axle" bottom level.

So the farther up the stick you fill, the axles are in a bath of oil so to speak.
There seem's to be good and bad info about running the oil level up farther on the axles.

Basicly I'm still a little lost on where the best fluid level is,..... well at least I know at the drain plug is stock.
So thats where it is for now,.. in tell I read more, and see about it being ok to run it higher.

 

Thanks for the post, I just got a mag hytec ordered in and need to put it on this week. Let me know how much oil I should put in when you get it all figured out.

 

the covers add...

3 1/2 to 4 qts in the rear and 3 qts in the front

I have all 3 covers and when i changed them...

7 quarts went in the front
8 quarts in the rear
18 quarts in the tranny. I flushed the system though so, that includes the torque converter

 

I guess I should add I had under 12,000 miles on the truck and used Amsoil 75 / 140.
I plan on towing alot and having a heavy trailer.

tritont, so your not worryed about running the oil up on the axles and into the bearings?? And that also means thats about 100.00 bucks worth of oil going in the diff........ummm no big deal if it never wears out. well worth it.

 

I don't see that I've done anything but, added the what the extra capacity cover enabled me to. IIRC, the fill hold on the stock cover was much higher than the Mags fill line.

You aren't kidding about the cost ! I used Lubrication Engineers and think the cost is well worth it with them.

 

On my F150 and my dak and my Bro's dak, we run the gear oil up to the middle of the dipstick.

I like the idea of keeping the bearings and seals in a constant oil bath. Otherwise they are dry on startup after sitting overnight.

Tony

 

I think putting in 8 quarts puts the level way above what the stock mark was on the OEM cover.
I still have to do some searching to find any info on running a higher level.

 

In the reading I've done here and on other sites it seems our trucks come stock with very low gear oil. Many guys have had to go back to dealer with whinning problems. Just thought I'd throw this in as everyone should check there levels.

As for the 8 qts. The 11.5 takes 4 qts to bring it to the level line. The Mag-hytec cover enables 4 more qts. Their web site even says " minimum 8qts."

At 8qts, the level is right where it should be on the dipstick. Ok, maybe a tad higher but, that's ok.

This is a exerpt from a owners manual......

The fluid level should be 1/4" +- 1/4" below the fill hole on the 9.25" Front Axle. The fluid level should be 3/4" +- 1/4" below the fill hole on all 10.5" and 1/4" +- 1/4" on 11.5" Rear Axles.

I think if you had too much oil then you would see it coming out of the vent before the bearings.

 

There is wording and a scribed mark on the stock cover. I took that mark and measured down to the bottom of the axle housing then transfered that over to the Mag Hytec cover. If you fill to that point, there is a little over 5 quarts in the rear end.
At any rate, there's do doubt the level will be higher with 8 quarts and the Mag Hytec cover than what came stock in my truck.
I poured the old nasty oil back into the bottles and there was very close to 4 quarts came out. And with only a hair under 12K on the truck, that oil was some nasty looking stuff. I'm glad I got it outa there.

 

Put mine on and added 2 GAL of Amsoil 75-90 Synthetic, right on the bottom line. Also hung a nice set of chrome bull nut while I was there. Looks good together.

 

Nice WW trailer

 

I added 7 1/2 qts to the level line on dipstick, went for a drive and rechecked, and added another 1/2 qt.