Just need help figuring out what brand & weights of gear oil are needed for both differentials. It is almost camping time and I would like to change diff. oils and inspect gears and wear patterns, before towing. I only have 6000 miles on truck but would like to check things out. I have read my manual....75w-90 synthetic gl-5 in both diff.s, but a TSB states 75w-90 in front & 75-140w synthetic in rear. Also, who makes the Coastal gear oils at ADVANCE/AUTOZONE? And who makes the Walmart syntech or what ever. The 75w-140 Valvoline synthetic I found at Napa contains friction modifiers/additives for limited slip & the TSB states do not use additives in our diffs.(Trackrites). Please, if the oil you prefer does not meet the required gl-5 as Dodge requires, do not suggest them. I know there are great synthetics out there, but I want to be sure my warranty stays valid (I am almost afraid to swap my wiper blades).

 

Approved, GL-5, and works well - Mobil 1 75w90 synthetic gear oil. Available at most auto parts stores and makes no noise/chatter in my LSD. The tsb on 75w-140 is for the rear and if you tow really heavy loads consistently. I believe most are running 75w90 and changing every 15k.

FYI xbowtie - the statement about not adding friction modifier has been misunderstood on this site multiple times. They just don't want you using ADDITIONAL friction modifier in your gear lube. Various gear lubes will have some small level of friction modifying additives - in fact 99% do, and most don't advertise this. This amount that's present in normal gear lube is fine - there is just no need to add any extra - which some lsd's in the past required.

Hope this helps!

 

Thanks Lightman, the $ for 75w-90 vs 75w-140 makes me happy , I can afford to change it more often $8 vs $14 per quart.

 

My opinion is 75w140 in the rear if you tow heavy. If your a commuter yuppie get someone else and you can afford it. For the light duty hauler 75w90 front and rear. I fancy ROYAL PURPLE because amsoil says to me I AM SOIL snake oil .....

 

"My opinion is 75w140 in the rear if you tow heavy. If your a commuter yuppie get someone else and you can afford it. For the light duty hauler 75w90 front and rear. I fancy ROYAL PURPLE because amsoil says to me I AM SOIL snake oil ....."


I don't understand what you mean by "get someone else and you can afford it"? Also what is a commuter yuppie? I do drive my truck to work, but I bought it mainly for towing my camper on trips. Is the Royal Purple approved by Dodge? I just want to change my diffs fluids, while meeting warranty requirements, and do in the most affordable way.

 

Royal purple is approved by all the requirements set forth by D C. I am running it and love it. I have a local speed shop that sells it for cheap!! It is daymotorsports.com. They are a circle track supply house and sell tons of it to racers. I even use their motor oil. I plan on using it in all my vehicles!!!!!

Brad

 

Since I tow heavy, I user Redline 75W140 in my rear axle. My first ring and pinion went south using DC's expensive stuff and I sure have no faith in it. The tech that repaired the axle agreed with my choice of Redline and the heavier viscosity. The friction modifier will not be detrimental to your axle. DC only requires that the oil be of a specific viscosity and meets GL5 standards. Redline meets those requirements.

Casey

 

Mobil 1 75W-90 in the front, 75W-140 in the rear. I did Mobil 1 75W-90 front and rear on the the 1st 15k mile change and it came out looking very good on the next 15k mile change, like dark olive oil. With the 75W-140 it seems to make for less 'drivetrain gear rumble', especially when shifting into top gear at say 55mph. I might just add a bottle or two of 75W-140 to the 75W-90 at the next change, and if it still looks pretty clear extend the change to 30k miles. The Dodge gear oil looked like black snot at 15k miles.

 

Valvoline 75w90 Synpower! Full synthetic, Meets GL-5, less than $8 per quart, you can by the same oil for the front and back. They sell it everywhere. I am kind of biased to Vavoline, I like to keep it simple, use their products for all my uses.

 

i agree with casey i dont tow anything so i run 75w-90 redline in both diffs if u tow use 75-140 for the rear. everyone has opinions on what brand to use but i would stay away from those costal or walmart off brand lubes, mobil 1 good i just think redline the best u can get IMO