2nd Gen Non-Engine/Transmission Differential fluid changes.

[MGordon]

I changed differential fluid yesterday at 15,000. I also went to synthetic in the rear axle.



The old rear axle fluid looked fairly dark as I expected. The front axle fluid was almost as clear as the new stuff I put in.



I am considering replacing front fluid every 30,000 and the rear fluid every 15,000. Or do you think this schedule is to frequent considering that I am using synthetic fluid.



Any opinions?

 

[illflem]

I think your schedule is too frequent even if you were using dino oil. You can't tell anything at all by just looking at an oil. If you really want to find out how often to change send in some oil samples at different mileages. My bet is you can go at least 50k with synthetic in the rear.

 

[MGordon]

illflem,



That sounds like a good idea. Could you give me some places that have the sampling kits and would do the analysis?

 

[jlhartak]

I'm with Illflem, I'm going with synthetics all round, I plan to run the rear at least 30-50K, and I don't plan on ever (well maybe 100K or so) changing the front again unless I see signs of moisture, etc.

 

[illflem]

oil analysis

A lot of folks here use www.blackstone-labs.com/

I personally use my local Cummins dealer for about half the price ($9) If you have a Caterpillar equipment dealer near you they also provide the service.

 

[MikeBeggy]

For the relative insignificant cost of oil compared to the cost of truck or even axle repairs, I vote for changing any oil more frequently than suggested by the maintenance schedule.

 

[illflem]

You're right Mike but your time and oil disposal hassle are the major cost. Lube quality has evolved tremendously in recent years while the manufacturer's recommendations for later models haven't, most of the older recommended intervals don't really apply nowadays. If I'm not mistaken the manual's engine oil change interval on a '03 is 15K, it isn't all due to the new engine type.

 

[mimprevento]

front Diff

I just had Mobil 1 put in the front diff by the dealer after 40,000 miles. I had the rear done with Mopar synthetic 75w-140 at 20,000 and I am leaving it in until 60,000- I do not tow. The dealer used a cleaning fluid after they drained it and I got the truck back with the paint gone off of the front diff. Is any automotive flat black good to spray on there?

 

[jlhartak]

Prevento, If you have any rust you could use rustoleum rusty metal primer as a base, then topcoat with rustoleum flat black.

 

[mimprevento]

Front diff

Thanks. Will do