Red Line 75X90 Gear Oil w/ MagHytec Cover???

[Buffalo]

As I said, I have the MagHytec rear-end cover with Red Line 75X90 with about 41,000 miles on it. Some towing of a 25' travel trailer.



Yesterday, I checked the dipstick magnet & it had a bit of a very black substance, on the tip. I wiped it off on a paper towel & it looked like the residue if you checked the engine oil on my old '91. 5 W-250. The substance is quite black but, I did not notice any metal shavings or anything that looked like chunks or metal debris on the towel.



Is this abnormal, or normal, for this many miles on the gear oil. The gear oil was still quite clear with a very slight discoloration. However, I don't remember what color the fluid was when new. It felt good, like it was still able to lubricate & had the familiar gear lube fragrance. The fluid still looks good to me but, I'm not sure about the black substance?????



Any thoughts???



Thanks.



Joe F.

 

[rbattelle]

If the black stuff is magnetic, it's just tiny iron particles. I get the same stuff stuck to the magnets on my transmission dipsticks. Perfectly normal.

Ryan

 

[Buffalo]

Thank you for the reply.

Now, I can sleep at night!!!



Joe F.

 

[macdaddy]

I've always had that when I check mine as well. It's normal.



Mine is always clean (Mopar 75/140). Even after 70K. I'll let this next one go for 100K.



Mac

 

[Buffalo]

macdaddy,



Are you concerned about going 70K to 100K miles on a fluid change? The factory recommended 15K miles between changes. I called the axle manufacturer when I first bought my '03 & the engineer I talked to was surprised at the frequency of fluid changes that Mopar recommended. He thought the axles would go much further. However, I don't know if 70K,100K is too many miles between changes.



I'm at about 41K miles, now & the fluid still looks good, in my uneducated opinion.



Thanks for your reply.



Joe F.

 

[rbattelle]

The debate over the axle change interval has raged since the dawn of the 3rd gen trucks. I don't think we've ever had complete agreement, but suffice to say most of us think the 15k interval is rather silly.

Now, having said that, I changed mine every 15k until 60k miles for warranty purposes. Now that I'm past warranty, I'm moving to a 30k change interval.

However, even 30k is a pretty short interval, so I'm not surprised that people go much longer. I don't think anyone can say definitively "xxx is too long" - each of us must choose whatever lets us sleep at night.

-Ryan