Switching to Synthetics ??

[weighit]

Have a 1999 International 4700 with the 300hp Allison. Right now it is getting ready to hit 70,000 miles. Have been using Rotella motor oil, and had the trans fluid changed about 3 years ago to synthetic. Wondering if changing the rear axle lube to synthetic would be of any benefit? I change motor oil at about 7500 miles, and have not switched that over. The motor does not use or burn any oil between changes.

 

[Jerry-5TH]

Stacey,
Changing the rear diff to synthetic is a good move, like the Allison. However, in our application the engine is not, based on the cost of the synthetics. I have the same rig as you and I use oil analysis and change my Rotella T every 12,000 miles. The oil analysis says I could get 15-18,000 on the oil, however I like to see fresh oil in there more often. As a retired HD truck factory service rep, I've had lots of experience with synthetics. There is a payback for the major fleets to use it where they run 100-200,000 miles a year, but not the way we run.
Jerry

 

[weighit]

Jerry; how many miles are you putting on your truck per year? After about less than a thousand miles or so, the oil looks so black, and dirty, not like a gas motor oil. I think I will get the oil and rear lube changed within the next few weeks.

Stacey,
Changing the rear diff to synthetic is a good move, like the Allison. However, in our application the engine is not, based on the cost of the synthetics. I have the same rig as you and I use oil analysis and change my Rotella T every 12,000 miles. The oil analysis says I could get 15-18,000 on the oil, however I like to see fresh oil in there more often. As a retired HD truck factory service rep, I've had lots of experience with synthetics. There is a payback for the major fleets to use it where they run 100-200,000 miles a year, but not the way we run.
Jerry

 

[Tetoner]

I switched from Rotella to Amsoil synthesized oil in the Cat engine in my previous truck and it would use from 8 to 10 quarts in 10,000 miles. With Rotella it would only use about 2 quarts in the same amount of miles. It had the Amsoil in it when I traded it off. I'm sticking with ROTELLA and about a gallon of Lucas in this truck.... (it holds 41 quarts)
Mike

 

[Jerry-5TH]

Stripit,
I am running 12-15,000 miles per year. When diesel oil turns black, it is doing the job it is designed to do, keeping the combustion carbon in suspension. Then, a quality filter can remove most of it.
Jerry

 

[weighit]

I'm going to call around tomorrow to see who can change the oil for me. The intermnational dealer is about 50 miles away,so a small truck repair shop about 10 miles away might be the next best thing. Will post what I find out.

I only go thru about 2 qts in 7500 miles of Rotella, so it seems to be holding it own??

 

[MarineChief]

Hey there to all:

We're running a '03 Freightliner SportChassis and I converted it to full AMSOIL synthetic lubes at the appropriate (first) oil change intervals. Unlike others, I have not had to add even a quart of oil to the engine since I made the switch. I'm first made the switch on the engine and differential, later to be followed by the Allison transmission. Since the engine is a Cat I haven't yet installed the AMSOIL double bypass filter (which should further extend the oil change interval). This is only for the lack of knowledge for a good point to return the oil to the engine (without punturing the pan with a hollow bolt). Anyway I feel that the synthetics offer a better overall protection. OTR truckers have gotten up to 130,000 miles between oil change intervals when using synthetics AND the bypass filtration.
Just as an extra note - I don't lean toward any additives into the oil such as "slick50" products and thier equivalents.

 

[5thwheeler]

I'm sold on synthetic oil and use it in everything. There is a clear proven advantage to them over conventional dino based lubricants.
Some say that due to the cost they are not practical in certain situations however oil analysis has shown me that longer drain intervals are possible. With this in mind we use it because we are on the road much of the time and its very convenient to not have to service the truck on a mileage schedule. We also use synthetics for better protection in hot climates due to its superior high temp protection and in cold climates due to its lower pour points and cold flow characteristics.

My wife once had a leased vehicle and someone called me a fool for putting expensive synthetics in it since I would never benefit from the longer engine life. This person changed their oil every 4-5 thousand miles and if you figure it cost $19 per change and a 45000 mile lease it cost him $171. I put in a high quality true synthetic and filter and put 39k miles on the same oil for $40.