I'm going to move over to synthetic as soon as I can.<br><br>My question is when to make the move. I only have 6K on my truck. I'm going to be putting a DDT tuned valve body in the tranny and a double deep Mag Teck tranny pan. This would be a good time to make the switch??<br><br>When is it recommended to move to synthetic for...<br>Tranny?<br>Engine?<br>Differentials?<br> <br>And, is Amsoil considered the best of the synthetics?

 

Bull Dog:<br><br>I'm not positive about the Trans and differentials, but I think any time is OK for those units. I went to synth in my differential at about 15,000. For the Transmission, I believe that DTT doesn't recommend synthetic. I had Bill K's version of the Pacbrake and the trans. Smart Controller installed last summer. The installer (DTT certified) didn't use synth, but I don't remember the brand or type. For the engine, you should wait until 9 or 10k miles before you switch. <br><br>I use Amsoil and am very happy with it. There are many people here who use it, but there are many other brands that are good, also.<br><br>I hope that this helps.<br><br>DeWain

 

engine: 10K if you worked it hard, 20K if not.<br>diffs: whenever<br>tranny: when I got my DTT tranny, Scott (MassDiesel), put in Chrysler ATF+3<br><br>Hope this helps!<br><br>Tony

 

<br> Engine: When I'm sure it's broken in. I'm thinking 20,000-25,000 miles.<br> Differential and tranny, from the beginning should be fine.

 

I think you are to wait till 20000 for synthetic oil in the engine but if your going with a new tranny ask that company for there recommondation.<br><br>KC

 

Im staying with Rotella T / Engine. Had 2 other CTD totaling 500K + never a problem. ran better everyday.<br>Built tranny gets +3 ,stock tranny gets +4<br>4 slips too much.<br>Syn in everywhere else at any time.<br>Heres something ( I don`t know who will agree) my motors stop smelling at oil changes once they break in, also oil stays much cleaner.<br> Danny

 

danlit:<br><br>I didn't really think about it, but you are right, I've never gotten an oil smell at change with the Amsoil.

 

Second or third oil change on the engine is fine. After an automatic rebuild, break it in for a few thousand, then switch.<br>If I had to choose one component, auto tranny would be first one I would switch.<br><br>Other components, as soon as possible.

 

I put synthetic in all the gear boxes before 20000 miles and in the engine at 24000 miles.

 

[quote author=DPG link=board=7;threadid=9164;start=0#88108 date=1041651995]<br>danlit:<br><br>I didn't really think about it, but you are right, I've never gotten an oil smell at change with the Amsoil.<br>[/quote]<br><br>I love the smell of Rosemella. I will alway use 15W40 Rotella T, it smells good when it is new. Plus, I would be too old to drive by the time I put over 500K miles on this truck.

 

At 75K + a year it doesn`t take long.<br> Danny

 

I switched everything to Amsoil at 50K, but I only got the truck at 47K.<br><br>Cummins recommendation for synthetic is 20K.<br><br>http://www.cummins.com/na/pages/en/p...2180C4A8F00000<br><br>Chris

 

I use Rottella in the motor. Really like it. In fact it's pretty good with some tonic, gin and ice cubes on a hot day ;D

 

[quote author=Bull Dog link=board=7;threadid=9164;start=0#88030 date=1041641185]<br>I'm going to move over to synthetic as soon as I can.<br>[/quote]<br><br>What Brand are you going to use? Are you going to use oil sampling and test it a what intervals? How do you use your truck? Where do you live is it real cold in the winter or real hot in the summer?

 

What Brand are you going to use? <br>Unsure, that's why I started the post. The dealer will warrant the CTD for 300,000 miles as long as I get the oil changed by them ... but I have to do 3,750 mile oil changes.<br><br>Are you going to use oil sampling and test it a what intervals?<br>I'm not sure about this. Is this really necessary?<br><br>How do you use your truck?<br>Using it fo a 50 mile work commute and pulling a fiver whenever possible.<br><br>Where do you live is it real cold in the winter or real hot in the summer?<br>Baltimore, Maryland - winter's average 20-30s, summers average 80s-90s<br><br>I kind of like the idea of going with a synthetic but I'm not convinced that the cost is justified.