Engine/Transmission (1998.5 - 2002) Differential Fluid Level

[WWalters]

I've read 56 threads on the subject. The consensus seems to be that the stock Dana Models 70 & 80 are underfilled as they come from the factory. My truck has the model 70, which according to the owners manual, should be filled to 3/4" +/- 1/4" from the bottom edge of the fill plug hole. I have a 2001 DC service manual which states the differential level should be to the bottom edge of the fill plug hole. In addition the manual states that the dry fill capacity of the 267RBI is approximately 7. 0 pints.



Owners of the Mag Hy-Tec differential cover have stated in their posts that with the additional fluid added as a result of the Mag Hy-Tec cover, the differential seems to be over filled; but that's not really the case as the extra fluid is beneficial.



In one of the posts, one member said that he parked his truck on a slight incline so that he could add another quart of fluid to get the level to the bottom edge of the fill plug hole.



I'm getting ready to change the fluid level in the differential, so I guess that my question is, should I put in the full 7. 0 pints even if I have to park the truck on an incline to so? Or, should I just make the change with the truck on level ground and put the fluid in until it starts to run out.



Thanks.

 

[Gary - K7GLD]

My personal opinion, is that the fill hole in the stock Dana 80's is TOO LOW, and even when filled right to the point of running out the hole, will not be properly full - especially critical in heavy towing situations where MAXIMUM lubrication may be critical. I plan on soon draining my differential and refilling with synthetic in the 90-140 weight range, and will make every effort to raise the rear end of the truck to crowd in as much lube volume as the fill hole will allow.



I realize a few fellas are concerned about various seals and such, but I'll take my chances with too MUCH lube, rather than too little...

 

[Texas Diesel]

This was in the latest edition of Lube Tips:



> TODAY'S TIP

>

>

> When rolling element bearings are lubricated from

> oil held

> in a sump, attention to the oil sump level indicator

> will

> not only bring savings in terms of extended bearing

> life,

> but also will lead to reduced bearing temperatures

> due to churning

> and metal-to-metal contact resulting from possible

> oil starvation.

> As a general rule, the lowest rolling element should

> be half

> covered with the oil, when the bearing is

> stationary. This may

> seem like a simple rule to observe but it is

> suprising how

> often it is completely overlooked! (Submitted by

> Derek Peasley,

> FAG Bearings. Thanks Derek!)



I run my oil to the highest mark on the MagHytek dip stick.

 

[Dane]

I keep mine at the top of the Mag Hy-Tec dip stick full indicator. No leaks with 25,000 plus miles.



I thought I had a leak on both sides, turns out I over lubed the wheel studs

 

[Pit Bull]

When I did my rearend I backed the truck up to the garage door which put it on a slight incline. Filled with Mobil synthetic 75w90 gear lube till it came out of the hole. Turned it around and then did the front the same way. All I know is it has more in it then it had before and it has better lube then it had before.