Hi all, confused by the vast amount of info I keep reading. First I have a 2001 5.9 R/T durango. It has 3.92 Rear Axle Ratio (as per the manual my tow capacity is 7250 lbs 4x4) Corporate 8.25 Rear Axle. The manual says to use 80W-90 in BOTH the front and rear axles. I also need to friction modifier to the rear since its LSD (limited slip differential). This R/T didn't come with the tow package which from what I see is the transmission cooler, a power steering cooler, and fold-able mirrors. I just finished adding a transmission cooler. I will be towing more frequently in the coming weeks so I am confused on the fluid situation. I have read on here that 75W-90 is availability in synthetic and that is made for towing (hence why it comes in the 9.25 rears), BUT i have also read that its doesn't hold up as well to 80W-90 long term.

Anyways wondering if anyone had any advice here. I don't want to buy Royal Purple either its ridiculously over priced imo.

 

I didn't realize any Durangos came with 8.25 rear ends. I thought all Durangos had 9.25 rears and only some Dakota's still came with 8.25. Especially an R/T Durango you would think they would put a 9.25 in there. That's what mine has. As far as the weight, I don't really know. My mind is blown just by the fact you gave an 8.25 because I didn't think it was an option.

 

For towing, I think you want 75W140 in there.......

 

My Dakota has the tow pkg. It has all the things you mention, but it also has a plug under the dash, where I can connect a trailer brake controller. Not sure what you're towing but having your trailer brake along with your vehicle saves a lot of wear and tear on your brakes...also safer.

 

I read that in the ram forums but none of the Durango manuals mention that. At 140 I'm not sure how good of protection the gears will get long term.

Interesting any chance you can snap a few photos of what that looks like? I def need to get a break controller but haven't read that the Durango come with the plug in for it.

 

The Durangos do. I haven't personally seen mine but I've actually looked in my Factory Service Manual and it mentions this plug. All you should need is a brake controller and the Dodge style harness to fit this plug. Splice the controller wires to the harness, plug the harness in and it's done. If I'm wrong someone correct me but I've read that on many threads here. I tow the heavy stuff with my other truck so I haven't bothered with a brake controller on the Rango yet.

 

I bought my '01 R/T new. In the glove box in a plastic bag on day one was a pigtail plug for that under dash towing socket, with 8" of wire hanging out to wire to your controller of choice.

The R/T is AWD, so the rear never has to manage the 4900 lbs alone.

 

I had no idea they came with the plugs, that's cool. I bought mine 5 years ago with 218,000 miles on it so that pigtail was long gone and that's true. I forget the R/T's are AWD all the time. I have the 242 T-case so I have the "AWD" option as well but I keep it in two if it's dry out.

 

Only if you have the tow pkg. Of course, you can always install it yourself. I will try and snap a pic. It's been years, but I believe it was just a simple plug. When you get a brake controller, you buy the right harness to connect it. You look them up by vehicle.

 

Would appreciate if you could snap that pic.

That is an interesting point. I wondered how the tow rating was so high for the 01 5.9 seeing as it only had an 8.25 rear. I read that there were some 9.25 (3.92) on some R/Ts but I have yet to see one. But I guess the AWD helps split the load when towing.

Don if you get a moment can you snap a pic and share (harness connecting and dongle)? The truck I picked didn't have the tow package (trans cooler and psu cooler)

As far the fluids manual says 80w-90 in both the front and rear but I am thinking of going with mobil1 75w-90 since its synthetic and of course adding the 5oz of friction modifier to the rear since I have limited slip.