I am getting ready to change my gear oil in my rears. I do both loaded and unloaded running. My gvw loaded is 18k. What is the best gear oil for this kind of application?

The other question is coolent. What is the best coolent for this Cummins?

Thanks for the help

 

Synthetic in the diffs, definitely. Mobil 1 is available just about everywhere. Watch out for the synthetic blends, the label usually says "SYNTHETIC blend", they're trying to sucker people into thinking it's synthetic.

Plain ol' green in the radiator.

 

Good green type coolant, and your running pretty heavy. If your in a warmer climate I would use 85/140, otherwise I would stay with 80/90 and change regularly.

 

on a side note. i want to flush my coolant soon and was wondering what i should run through system to losen and rid all teh calcium lime deposits i can see on teh fins when i crack the RAD CAP. thanks. jiMMy

 

When you guy's say Ol Green are you refering to plain ole Zerex?

I remember the last time I changed the gear oil it I couldn't determin for sure if it would take synthetic. I couldn't fined a listing for synthetic anywhere. Is it written somewhere that its ok to put it in?

Thanks guys

 

Yeah, Zerex is fine, Prestone, even house brand, as long as it's normal green anti freeze.

There's nothing wrong with using synthetic gear lube, in the owner's manual for newer trucks Dodge requires that you change to synthetic if you're going to tow heavy. Get Mobil 1 80W-90, and don't forget the limited slip additive for the rear diff.

 

Ok thanks Dave. I was going to change to synthetic last time but no one could find a listing for the ole Dodge and synthetic so I just kept puttin dyno in er. I guess I'll change. I know I'm a bit heavy so I wanted to do whatever I could to help er out.

Hey how about a flush. It it a good or bad idea?

 

If you're talking coolant, I don't like to flush old vehicles with a chemical flush. You usually end up flushing out a chunk of scale that was plugging a leak. Backflushing with water is pretty safe, but it's rough on the lawn.

If you're talking the rears, I wouldn't bother. Just get 'em hot and pull the covers, you'll get most of it out that way. All that will be left is what's hanging out in the axle tubes and the hubs, and you could change the gear lube 3 or 4 times and it would still be the same oil laying up in there.

 

Yeah that's what I was thinkin. I was talkin about the coolent. I normaly just run water though it drain and fill with distilled and antifreeze.

 

Sounds like a weener.....uh, I mean winner

 

I use Fleet Guard ES Compleat and ro water.

 

I use castrol syntec in my difs and cases. I have a jeep that went 180000 before needing any axle/bearing work, and the crappy track lock still works at 210000. They usually bomb out and wear much sooner. That' advertisement enough for me.

 

Fleetguard ES Complete here as well