My truck's rear end looks like gray sludge. How do I drain the differential on this truck? Do I need to take off the cover or can I drain out of a certain cover bolt hole? Thanks

 

Pull the cover. If your seeing gray sludge you may want to check you wheel barrings and races, dif. gears and seals.

Greg

 

Like Falcon1 said, pull the cover. That allows you to look at the magnet thats in there to see how much crap is stuck to it and also look at the bottom of the pumpkin to see what is in the sludge there.

 

I'll third that motion, pull the cover! Is that grey kind of a milky color? if it is, cheap insurance to change out the wheel seals, check the bearings, and make sure no holes in yer breather; could be water infiltration---baad ju ju. If you pull the cover and find chunks, don't feel too bad, these diffs make some of the best examples I've seen for what spider gears are not supposed to look like. he he he. It seems that when you get a cummins, a severely shortened wheelbase, and a 7:1 rear axle ratio(not a typo-yes I've counted the teeth) the flightline weenies like to pop wheelies. Good luck!

 

While on the subject, my rear end is supposed to be anti spin. I never thought about it at the time, but have since, when I did the rear brakes I could easily spin one wheel with the other still on the ground (and xfer case in N).

Apparently my anti spin either has been removed, or is not working. I need to change the fluid in the rear end but was waiting until I had the correct friction modifier. Now I wonder if I should have some replacement parts for the anti spin on hand too?

Sorry for the hijack,

JP.

 

JP, the clutches are probably shot. If they've worn as badly as mine were (I thought I had an open diff, too) you will need new side and spider gears. Worst case scenario is a little over $200 and about 3 hours of your time. Reider Racing is where I got the parts to fix mine.

You ought to pull the cover and inspect the diff before ordering parts, because you may only need clutches (around $50). Gotta pull an axle to count splines, too.

If your side and spider gears look kinda like this it's time for all new internals.

 

Back to the original, I opened it up today and found what appeared to be shavings that reminded me of drill shavings minus the corkscrew shape. All the gears were in tip top shape. Pulled off the hub and all parts were accounted for, but maybe a little slop in the bearings. i sealed it back up and am taking it to a professional on Tuesday.

 

Sounds like a good idea- the Dana70s are also known to throw shims as well, messing up your bearing preload.

DP