I was wondering about good synthetics. Like real synthetic base or petrolium base. I've heard that Mobil and Amsoil are true synth. I got some Valvoline synth. at NAPA on sale yesterday($17.xx/gal.) it has the big blue Cummins 'C' on the label as being approved. It's called Premium Blue Extreme. I haven't put it in yet, gotta get a new ratchet for my drain plug. Some dork :-X put it on too tight.

 

I've used Amsoil for years, 18+. I believe in it, and have never made a dime on it. I continue to use it. In everything from my chainsaws @ 100:1 to my trucks from front to rear. I started slow, and worked my way into a full syn program. It took a while. I kept records, and found that I liked the stuff. It works for me. Form your own opinions. If you have a question related to synthetic products, or their applications, I will try to answer. To each their own, this is merely my opinion.

 

I think that drain plug likes to self-tighten. I use a breaker bar.<br><br>A ruling in 1999 by a government agency declared group III petroleum based oils as synthetic(Mobil 1 lawsuit against Castrol Syntec.) Group III basestocks use hydrocracking to refine petroleum purer, and is cheaper to produce than group IV PAO or group V ester type basestocks. However, end consumer pricing is the same as the higher end synthetics, as manufacturer's can now label group III's as such. Quite a bit of synthetic blends are on the market as well.<br><br>After much research, I switched to synthetic. Amsoil, Mobil 1, and Redline are IMO top line synthetics. http://www.bobistheoilguy.com/ is a great oil related website. On the forums there, you can read oil analysis reports, I've seen many on the Dodge Cummins. It gives you an idea what additive packages are in which oils, and how they perform on the long haul. Regards

 

What weight mobil 1 should be used. They have 0-40,5-30,10-30, &amp; 15-50wt

 

Don't use Mobil 1. It's not formulated for diesels. Use Mobil Delvac 1 instead. 5-40 is good and is rated API CI-4

 

I totally believe in amsoil I run it in EVERYTHING I run it in my 250 cc motocross bike at 70:1 mixed with 50/50 race gas in a full mod motor and I have never had an engine failier Amsoil is #1 in my books I also run it in my snowmobiles. Very very good product.

 

Changed front diff. Saturday to amsoil. I now have amsoil throughout, with no problems.

 

Amsoil prevents blow-by too!

 

since it seems amsoil is thing to run from what everyone here says, can yall give me some advice as to which ones to run in diffs and engine?, thanks<br>

 

You still have to make the call and run what makes you feel good since it's your truck. I will be glad to tell you what I am running but again, that is my preference.
All of these are AMSOIL products.
I am running Series 2000 75W90 in the rear axle and with the MagHytech cover, it holds near eight quarts.
I am running 15W40 Marine Diesel oil in the crank case and with the dual remote filter set up, it holds almost 14 quarts.
I am running the regular synthetic 75W90 oil in the front axle and it holds a little over three quarts if I remember right.
I am running the Series 2000 75W90 in the five speed and I forget how much it holds since I added the Transcoolers.
I am running the regular synthetic ATF in the transfer case and it holds around four quarts.
That doesn't mean that these are the best oils but I like them and have had good success with the products for over 15 years now.
Do the research and compare the numbers and then run what makes you feel the best. If you don't have access to these products and decide to use them, there are people on here that can get them for you, me included. Send me a PM and I can set you up if you don't have anyone closer to you.

 

[quote author=quantrill88 link=board=7;threadid=11092;start=0#106321 date=1045634219]<br>since it seems amsoil is thing to run from what everyone here says, can yall give me some advice as to which ones to run in diffs and engine?, thanks<br><br>[/quote]<br><br>If you like synthetics, along with Amsoil, there is Shell Rotella Synthetic, Mobil Delvac 1, Valvoline Premium Blue Extreme Synthetic.

 

Just gonna echo dieseldude4x4<br><br>An excellent list.<br><br>By all means, do your reaearch, and formulate your own opinions. What's good for one is not necessarily good for all.<br><br>Everyone uses their truck in different ways. Amsoil is my choice, in my truck.

 

Do your research carefully, the term &quot;synthetic&quot; is used very loosely any more. :-X

 

thanks for all ur help, guess i got some homework to do on them.....never knew there were so many differnet synthetics with such different properties