Engine/Transmission (1998.5 - 2002) New truck differential suggestion...

[Gary - K7GLD]

I've got 2300 miles on my new truck - just changed oil for the second time - and decided to also check the differential to be on the safe side...



The level was perhaps 1/4 inch below the filler plug - which itself sits pretty low on the cover - so I went and bought a quart of 90-140 wt Valvoline synthetic GL-5 gear lube. Back home, I parked the truck on a slight downhill, and proceeded to fill the differential right up to the filler hole... It took nearly the whole quart!



There's been some discussion in this group about some early failures of differentials, and suggestions that the factory fill plug and owner's manual suggestions on proper fill level is on the low side - in any event, since I tow a lot with my truck, and will be heading up along the N. Cal. and Oregon coast for a couple of weeks RVing, I'm sure glad I topped mine off... Wish I had checked sooner...

 

[MJawsman]

Be careful though as too much fluid could cause premature seal failure. If I'm not mistaken, 1/4 inch below the plug is considered full.

 

[Gary - K7GLD]

YUP - and THAT has been the major subject of discussion...



Considered "full" by WHO?



Seems MOST of the failures *I've* read about were using the "recommended" fill level... But time will tell...



I'd certainly rather replace a failed seal than the differential itself!

 

[Peter Campbell]

Check with MAG-hytech. To paraphrase- I think he runs the level higher. Into the tubes about 1/4 inch. this keeps the seals wet. If the seals are good they stay good. The bearings ( axle end) are also oil lubricated. This keeps a lube bath on them Stock level depends on the occasional turn to put oil back on them. If the seals get dry, and park wrong then your drum fill with gear lube ( how do I know this you ask ). I have the mag Hytech on the rear diff and am going to put one in the front. And the oil level is higher with no problems. Truck had 3000 miles when I put it on, so no chance to let the seals get damaged.

 

[MJawsman]

I agree with you. I spoke with an engineer at Dana several years ago when Dodge began to use the Dana 80. He made two suggestions. 1) Use 75W-140 synthetic gear lube, and 2) check backlash every 25K or so and adjust as necessary. He mentioned nothing about lube levels, but as Dana has been building axles since the wheel was created, and the fluid level has never changed, I assume (don't say it!) that they know what they're talking about.



Mark

 

[Gary - K7GLD]

Here's a pointer to another similar thread on this subject:



http://216.235.147.117/forums/showthread.php?s=&threadid=53162



This pretty much sums up my viewpoint based on other threads as well - and also reading over in the Ford group - they use the Dana series of differentials as we do - and have apparently come to the same conclusions on lube level...

 

[tarussell]

I changed my fluid in the rear axle at the 500 mile mark and used Valvoline Synthetic's . I put an F-450 finned aluminum Dana 80 cover on and filled the fluid level up enough to keep the axle tubes constantly wet. The only thing I am worried about is causing the gear oil to foam up if it has too much in it. Has anyone else had foaming problems? mine seems to be fine but I watch for leaks and check for excessive foaming.



If you look at the diff covers the area for the fill plug is flat for a few inches. It seems to me that Spicer allows some variation on where the manufacturer wants the fill plug located. If I do have axle seal problems I will replace the hub seals with a double lip Viton heavy duty seals. Hopefully that will take care of the cheap seals that DC is using. Just my $. 02 worth... .....