Trans and Diff Oil Recommendations?

[dewilmoth]

I'm almost to 1k miles, and I'd like to change the diff and trans fluid. I searched and couldn't find any specific recommendations for the fluids. Is everyone using the Mopar branded Castrol products, or are there better options out there? I know this subject tends to be Pandora's box. Thanks.

[kverges]

I'd like to know too as I was considering Redline Shockproof heavy for Diff

[Pappy]

If you have not noticed, the Castrol SAF-XJ/SAE 75W-140 Synthetic Gear and Axle Lubricant listed in the owner's manual has changed names to Castrol Syntrax 75W-140 Limited Slip Differential fluid. I don't know if the formula changed, or just the branding. I could not find any locally in Phoenix, and when I ordered it from Dodge it had to come from Michigan. The same Castrol fluid is recommended for the GT-R and BMWs. I was advised by a pretty savvy Viper tech to leave the differential fluid in for a couple of thousand miles in case it was specially formulated for break-in. I will pull out a couple of ounces and see how it looks at 500 miles. I heard from another source (I can't vouch for the validity of the information, but the source is generally credible) that the differential fluid may have been a factor in some of the recent gear whine. In any case, I'm not going to do anything radical with the fluids until I get smarter on the subject - I'll just stick to the factory recommended fluids for now.

Pappy

[dewilmoth]

If you have not noticed, the Castrol SAF-XJ/SAE 75W-140 Synthetic Gear and Axle Lubricant listed in the owner's manual has changed names to Castrol Syntrax 75W-140 Limited Slip Differential fluid. I don't know if the formula changed, or just the branding. I could not find any locally in Phoenix, and when I ordered it from Dodge it had to come from Michigan. The same Castrol fluid is recommended for the GT-R and BMWs. I was advised by a pretty savvy Viper tech to leave the differential fluid in for a couple of thousand miles in case it was specially formulated for break-in. I will pull out a couple of ounces and see how it looks at 500 miles. I heard from another source (I can't vouch for the validity of the information, but the source is generally credible) that the differential fluid may have been a factor in some of the recent gear whine. In any case, I'm not going to do anything radical with the fluids until I get smarter on the subject - I'll just stick to the factory recommended fluids for now.

Pappy

That's great info, thanks. I totally agree with not changing the fluid type unless there's a compelling reason. I think I'll definitely stick with the Syntrax for the diff since it is pre-mixed with the friction modifiers for the limited slip. I'm more curious what the consumer equivalent is for the Mopar trans fluid. I can't find any info on it, and I'd like to get smart on what it is. Like you said, I will likely stick with OEM unless there's a reason not to. I hadn't thought about the break-in formulation possibility, but it seems plausible, so maybe I'll stick with the factory fills for another 1k miles.

[Steve M]

Pretty sure the Gen 5 still specifies an ATF+4 for the transmission...as long as the fluid meets those specs, you are good to go. Castrol Transmax ATF+4 certainly fits that bill.

[dewilmoth]

Pretty sure the Gen 5 still specifies an ATF+4 for the transmission...as long as the fluid meets those specs, you are good to go. Castrol Transmax ATF+4 certainly fits that bill.

The manual does say "Mopar atf+4." Wondering if the Mopar stuff is anything special, or if any good atf+4 will do.

[Steve M]

Guaranteed that the Mopar stuff isn't anything special...someone else made the oil, and they slapped their label on it so they could charge twice the price. Chances are, it's Castrol just like the diff fluid.