My '03 3500 SRW CTD with the six speed started making a fairly loud clunking sound when taking off in first and second gears. Took it to the dealer who said they couldn't effectivley trace the sound unless I romoved my toolbox. The said it was making to much noise, standard BS. I agreed to bring it back on monday minus the toolbox. The tech said, when I spoke to him without the service manger that running anything other than the mopar gear oil will cause troubles in the diff's and he thinks the noise is coming from there. I run royal purple 75W140 in both do I believe him or not?

 

I have Royal Purple 75-90 front and 75-140 rear with no problems or undue noises so far (about 4K miles). Claim seems doubtful to me.

Dan

 

Yep, looks like the dealer is looking for excuses. I have been running Royal Purple 75w-90 in both my difs for at least 20k miles, no problems!

 

You don't believe him. Most likely your driveshaft u-joints are worn out. A very common issue.

 

Send off a sample of your Royal Purple diff fluid and get it tested. If it comes back within spec, then you can prove your fluid is not responsible for whatever problem you are encountering. As long as your fluid meets or exceeds the Dodge spec for fluids, they certainly would have a tough time proving that your fluid caused the problem.

Does sound like it is a driveshaft U-joint.

CD

 

I have been running RP 75wX90 in the front and RP 85wX140 in the rear on my truck since 10k miles. I now have 53k and a lot of that was towing a 10k 5th wheel. I also ran the same thing in my old 01.5 for 80k miles without a problem. I think your dealer is full of it.

 

RP in my diffs here too. No problems. Like CDinNM said. Pull a UOA and check the levels. Mine clunked too until I changed out the ujoints. Those silly things are tempermental in these Dodges.

Wood

 

i just changed out my rear diff fluid today. the fluid had 50,000 miles on it and was amsoil's severe gear lube 75w-90. fluid looked brand new!!

 

Over 150 with RP in diffs and transfer case with 0 issues. I recently changed them and remembered thinking how little wear the ring gear showed.


I agree with the other guys, quite possibly a u-joint. Clunks, shakes, vibes, you name it the u-joints can cause it in these trucks. For some reason a failing u-joing is more evident in a Ram when compared to my previous trucks.

 

Thanks for the input everybody. The dealer is working on the truck today. Once they determine whats wrong I'll post an update.

 

i am using the RP in both diff's on my truck. 10k miles with no problems!

 

Personally I doubt it is the gear oil causing a problem. If the gear oil you use meets the specs mandated by DC, then it doesn't matter who makes it. If they give you grief about running 140w oil instead of 90w oil, then show them the TSB stating it's OK to use in severe duty applications.

Good luck.

 

I heard from the dealer today, who informed me that the carrier was damaged, causing metal shavings to damage the ring and pinion and some bearings. The tech, who is being cool and fixing it under warranty regardless of the oil says that Mopar oil must be used in these limited slip rear ends. Either way FYI if your NV5600 6speed trans, with the limited slip diff is clunking it may not be U joints which is what I suspected too. Thanks for everyones input.

 

The tech is giving you a line of Bull. As long as you use synthetic 75/90 GL5 or better gear oil they can't void your warranty nor can they make you only use Mopar brand unless they supply it to you for FREE.

 

Magnuson-Moss act all the way on that one. It was specifically set-up for you not to be tied to dealership prices on things such as the "Mopar" fluids for warranty. I agree, if it is a synthetic 75/90 GL5 or better gear oil they cannot invalidate your warranty... but they may try to anyway.