I have just bought a 06, 5.9 Big Horn 3500, 90K miles to pull a camper. I am a big fan of synthetics and would like to change the transmission and transfer case fluid. I called a Dodge Service Manager and asked questions. He said it was no point in changing to synthetic at this mileage. (stay with Dodge recommended) However, I still want to do it and am looking for suggestions on which brand to use. The man I bought the truck for has had it for 18K of the 90K and said he had never changed any of the fluids. Please help with suggestions on what I should do.

 

Change the fluids out. I used Valvoline ATF+4

 

I used Castrol ATF +4 and no complaints. Its never to late to goto synthetic on the newer trucks. If its 20 years old, then stay with what you got.

 

Although not officially a sanctioned brand by Dodge, I use all Red Line synthetics… engine oil, transmission, transfer case, and differentials. They are expensive but they’re one of the few “true” synthetics. You could go cheaper but RL is a high quality product and they freely publish what’s in it. You can also call and speak with their engineers if you have questions. I haven’t found that with most other brands.

 

Is Royal Purple Max worth the extra money? I have used mobil 1 synthetic in all my gas motors for years and durning that time period I heard alot of good stuff about RP.

 

Idunno

The Valvoline I mentioned up there is full synthetic and runs $6.99/qt.

 

Ditto! I use Redline Oil in my tranny, diff's, & transfer case.

 

I'm using the Mopar ATF +4 in the trans and transfer case and Mobil 1 in the diffs. I'm just over 60K miles and will be changing all of the fluids this weekend. I'm having the trans done with a band adjustment every 30K, transfer case every 30K, rear diff was done at 15K, 30K, front diff was only done at 30K. I'm going to do the diffs again now at 60K then probably figure on every 60K going forward. The severe service spec of 15K for the diffs seems overkill, especially since I have the larger rear cover and the truck sees no water.

 

For me, It'll probably be Valvoline in the tranny, because I think that was what was put in it at the time of the tranny swap (Goerend, by the way!) I think the transfer case was done also with the same at the time! I'll have to check the records on that one! About time to do it again with the differentials! The differentials were Redline though, and will use the same again!

 

here is the best. get one gallon synthetic syncromesh sae50 transmission fluid and mix it with one gallon 5w-30 synthetic syncromesh transmission fluid and pour 7 quarts in the g56, this is one quart over full to lube and cool the front bearing. brand not important. royal purple, amsoil, red line, shafers, dello, delvac and others make them. in the transfer case use the sae50

 

Unfortunately, it is not. A true synthetic oil starts with a PAO base stock - synthetic, and fully man made. It has a few properties that make it desirable in some applications. It is also more expensive.

There are only 4 true synthetic oils on the market; Royal Purple, Redline, Amsoil, and another I can never remember (Schaeffer?). I use Royal Purple in my race car, and it's about $10 a quart.

Cheaper "synthetics" like Valvoline and Mobile 1 start with a petroleum base stock, and are then highly refined until they meet certain performance requirements. It's a clever trick of marketing that allows them to be sold as synthetics.

There's nothing wrong with Valvoline, it's a fine oil. I use it in my truck, and the UOA's are always good. But if you're paying synthetic prices for petroleum oil, you're getting fleeced.

 

The ATF+4 is synthetic to begin with.

 

Oop you're right. I got that full synthetic - synthetic backwards.

 

I did all but the transmission fluids in my truck with 63K miles. I had the trans done with band adjustment a couple months ago at 60K miles. Engine I've been doing at 7500 miles with mobil 1, diffs were both done with mobil 1, transfer case was done with Mopar ATF +4. I did the fuel filter as well.

The diffs and transfer case had been done at 30K. The transfer case and rear diff were likely premature as the fluids coming out looked new. I have the mag hytec pan in the rear, so it does hold 7.5 quarts of fluid. The front diff fluid was a little dark in a clear jug after 33K miles. I may spring for the mag hytec pan for the front as it makes the fluid change so easy and you can check the condition of the fluid with the dip stick.

I finally succeeded in properly lubricating the grease fitting on the front drive shaft CV joint. I've tried with the needle fitting before and gotten at least some grease in there, but this was the first time I heard that satisfying pop of the grease pushing the air out of the joint and saw fresh red grease all the way around the joint.