Hi guys,


Haven't been on here in a long time, and I apologize if this is a constantly-repeated question.


I have a '09 Ram 1500 with about 29K miles, was always my weekend truck (had a work truck I drove most of the time), until recently. So, now that the truck is 6 years old, I figure it's about time to change the rear diff fluid.


I've never done it before, but changing the rear diff fluid seems straight-forward. I have a couple of nit-picky questions, though, and you guys seem to be the experts. Any help would be greatly appreciated.


Question #1) I splurged and decided to buy an after-market diff cover. It happens to have an o-ring where the gasket should go. There seems to be a conflict of opinions as to whether I should use the o-ring or not. So, do you guys think I should just use the included o-ring, just chuck the o-ring and use RTV, or use both the o-ring and some RTV together?


Question #2) If you think I should use RTV gasket maker (with or without the o-ring) - am I supposed to using the "Hi-temp" Red RTV or the "Oil Resistant, Advanced Formula" Black RTV? Or am I over-thinking it, and it doesn't really matter which one I use?


Thanks very much for any help.

 

I have always been told use RTV Black for the differential. I have read where the fluid will eventually eat through other types of RTV.

I've read of both guys using factory gaskets, Felpro gaskets, and RTV, or just RTV. Many success stories either way, so I honestly think it doesn't matter much. Of course you will get varied opinions from others here.

What fluid are you going to put in there?

 

I would just do what the manufacturer of the cover says to do. If the o-ring leaks, it's on them. Anyway, it should be fine with the o-ring.

 

Jason,

Thanks for the help. I have a tube of the Black RTV as well, but then I read somewhere that you might need the High-temp stuff. I think I will use the black, like you advised, and stop believing every dumb thing I read on the interwebz.

I already have the Royal Purple 75w-140 gear oil, just waiting on a day off of work to get it done.

Thanks again.

Pedro,

Okay, I think I will use the o-ring. I had planned to but, again like an idiot, I read one Amazon review that recommended to not use the o-ring. But then again, I read a bunch of reviews that did use it.

Thanks for the help.

 

there is always one guy who makes and idiot proof installation not idiot proof and then writes a review

 

Amen to that.

BTW, a good read for quality gear oil is here. People argue back and forth over the actual tests, as it was sponsored by Amsoil, but it still looks to me like some science at work. I purchased Mobil 1 gear oil partially based on it's results. I am also waiting on a good day, with little else going on, to change it.

 

Jason,

Thanks. I've seen that paper before. And I've read the arguments for-and-against.

I went to med school - and we had entire classes dedicated to "interpreting" scientific studies. A big part of the lecture was to always take a drug-company-sponsored study with a grain of salt.

Considering that RP is Amsoil's biggest direct competition - it seems more than a little suspicious that they did terrible in an Amsoil-sponsored study. And RP as a company has grown a lot more than Amsoil has in the years since that study - which seems unlikely that they keep getting more mainstream, but no one seems to have noticed that they have an inferior product.

Anyway, that's just my opinion.

Thanks again.

BTW - does anyone have torque specs for the front diff cover bolts? Are they to be torqued to 30 ft-lbs., just like the rear? I can't seem to find anything concrete about the torque.

Thanks a third time.

 

I've been using the mobil 1 stuff and it seems to be doing well. The color stays clear not like the factory fill. Torque? I never worry about torque with these things. If you use the high temp rtv stuff, you have to apply it, let it set, put the cover on and tighten some, let it set some more then tighten one final time. Just tighten to what feels good.

 

There are high temps and there are high temps. The diff does not produce the high temps that the red high temp RTV was designed for.

Don't over think this. You are mating two flat surfaces....pick an RTV and use it. It really is no biggy.

 

Thanks. I agree, I'm doing this today, and am just going to use the Permatex black stuff that I bought in the first place.

Thanks for all the help.