My question is, is it benificial to change your tranney, both diffs and transfer case out with a synthetic oil, and since I have a limited slip is there not some additive that I also need to put in. For the crank case I use Valvoline Premium Blue 15/40 which I think is a pretty good oil. Whith that said, at what mileage should you switch to a synthetic and also what type of oil do you guy's reccomend I have 18k on my truck now. Thanks for any input. Mike

 

Beneficial? I really think synthetics are the way to go because they don't break down, especially the oil.

You can go to full synthetics now with no problem. The Premium Blue 2000 that you are using is already no longer available at Cummins South (they can't get it anymore) and has been replaced by the full synthetic Premium Blue Extreme 15W-40.

On the differentials, I changed mine and went to the Valvoline Synthetic and no friction modifier was need for the limited slip. I have no chatter on turns and the rear hooks up just fine with both wheels.

I haven't done the tranny but I'm ready to and when I do I'll go full synthetic in it also.

 

I change everything mentioned about every two years. I even change brake fluid, power steering fluid, and even hydraulic clutch fluid every year. Change anti freeze and hoses about every four years.

 

Hey Smoke Dog, not so fast.....<br><br>He didn't say he was using Premium Blue 2000, he said he currently uses Premium Blue, which is non-synthetic. I too use Premium Blue 15w-40, and it is readily available at any Walmart.<br>As for using synthetic, I would suggest you wait until 30,000 miles for oil, but for everything else, you can switch now. Matter of fact, I plan to switch to Amsoil for the diffs - 75W-140 series 2000 for the rear and 75W-90 series 2000 for the front. The limited slip additive can be found at your local dealership (expensive) or any auto parts store (about $5.00 for 8 oz.), For a 4x4, you need 10oz. for the rear axle.<br><br>Tim

 

Dodge Manual says 10k if you work the engine hard, 20k if you don't -- for the oil (I'm still using Delo, I like it)<br><br>All other fluids you can change out whenever. Synthetic is recommended for the diffs (at least the rear) if you are towing. I use Royal Purple in both diffs, no friction modifier needed. <br><br>Still using Mopar ATF+3 in the DTT tranny, debating on switching to Amsoil or not... I also use Royal Purple Max-EZ power steering fluid.<br><br>Tony

 

The benefits of synthetic lubes are fire and ice, performance at temperature extremes. Good cold weather flow, and thermal stability at high temps. As already stated, will not breakdown, allowing extended drain intervals. <br><br>I had no problem with chatter on my LSD when changed to synthetic, however some have. I'd say try it without modifier first, then get some if you have any symtoms of the LSD not working properly.<br><br>I bought my truck last year with 60K on it, and other than engine oil, none of the fluids had ever been replaced. The transfer case by far, had the dirtiest looking fluid. I even changed the power steering fluid to synthetic. It groaned and chattered in cold weather and was difficult to steer until warmed up with the factory fill. Good luck.

 

Depends on where you live and how you use your truck. Gets cold where you live, but if your truck is alway in the garage and you alway plug it in, when it gets below 40 degrees then dino oil is great. If the most you haul is 2 - 50# bags of dog food and you never tow the synthetics are not needed in the diff's. Use the recommended DC ATF in your transmission and service it every 30K miles and it will last. Now if you park your truck outside and can't plug it in, along with towing 12K lbs trailers then I would look at going to Delvac 1 for the engine and Mobil 1 75W90 for the diffs. Run the Delvac 7500 miles using a Fleetguard Stratopore filter. Change the synthetics in the diffs depending on how much you tow. You will need to use Mopar Limited slip additive, but it seems like every diff is setup different. Try the Mobil 1 75W90 without the snake oil, and do some figure 8's if it pops add a bottle of the Mopar LS additive and do the 8's again, if it still pops then add another bottle etc. until you get it right. Don't add to much or you will disable your LS diff. Hope this helps JMHO

 

What is the differences in Gear oil weights? I live where it gets hot in the summer and very cold in the winter. What should I use for my diff. oils?

 

I'm a Redline fan for gearboxes, with Delo in the motor.

 

How much Power steering fluid do the 2nd Gen trucks hold?

 

If you have the money, synthetics are the only way to go. If you don't, oh well. Some people have claimed an extra 5 hp and some mileage when switching everything(engine oil, tranny, transfer case, both axles) to synthetic.

 

Can anyone say how many quarts I would need for the rear (D80) and the front diffs in my truck? I'd like to go with the Royal Purple or Redline, but have never seen it around here. Where do you all buy yours? My camper is around 4k pounds when fully loaded and I'm sure it would really benefit in the rear axle.

 

http://www.oiltown.com is where I buy my RP from...

I think it takes 5 quarts.. can't remember exactly, it's been so long...

Anyhow, buy a case from them and you'll have enough for both diffs...


Tony

 

Most any speedshop should have redline and/or other syns. Go to www.redlineoil.com and you can search for dealers in your area.

Towing the rear calls for 75W/140. Otherwise 80W/90 both front and rear. Rear on a Dana 80 is just under 5 qts. Front is a bit less if I recall.

 

For answer to your question on Gearlube weights, this thread should help.
https://www.dieseltruckresource.com/...threadid=47540

RJ