I posted a thread asking about this on a couple Dodge truck forums I frequent and didnt get much response. I thought I would post a condensed version here with a different question to get some opinions from the oil pros.
Basically, its coming time for me to change out the gear oil in my rear axle of my 2wd Dodge 1500. This will be the third change, the first being 75w90 (Royal Purple) that was listed as the correct fluid in Oreillys computer. The second being 75w140 (Mobil 1) that was listed to spec in the owners manual of my Uncles 2004 Ram 2wd.
Out of curiousity I started checking into this and broke out my falling apart 2002 owners manual and found that Dodge listed 75w90 for my 2002 1/2 truck, and in the 2003-on service manual, and the 2004-on owners manual it lists 75w140 except for 2500/3500 trucks, which should use 75w90. I was wondering why the change. Dodge 1/2 ton trucks are the same from 02-05. I have heard that the lighter fluid can be used if not towing, but why are the heavier trucks supposed to use 75w90, arent they expected to be the heavy haulers?
I am wondering about this from a cost stand point as well. I dont want to run the lighter fluid if the weight was raised due to a problem with it, but I also dont want to run the heavier fluid at the heavier expense just to drain good fluid out at 30,000 miles. The first 30,000 miles I ran the RP 75w90 it drained out with the same reddish purple color that it went in with. I also have an open diff if it matters. Any ideas or opinions are welcome.
Here are a couple shots from my 2002 manual:
It doesnt even say to use synthetic (which I will use anyway), just GL-5 Hypoid gear oil.
This is from the 2004 manual:
Here are some shots from my
Basically, its coming time for me to change out the gear oil in my rear axle of my 2wd Dodge 1500. This will be the third change, the first being 75w90 (Royal Purple) that was listed as the correct fluid in Oreillys computer. The second being 75w140 (Mobil 1) that was listed to spec in the owners manual of my Uncles 2004 Ram 2wd.
Out of curiousity I started checking into this and broke out my falling apart 2002 owners manual and found that Dodge listed 75w90 for my 2002 1/2 truck, and in the 2003-on service manual, and the 2004-on owners manual it lists 75w140 except for 2500/3500 trucks, which should use 75w90. I was wondering why the change. Dodge 1/2 ton trucks are the same from 02-05. I have heard that the lighter fluid can be used if not towing, but why are the heavier trucks supposed to use 75w90, arent they expected to be the heavy haulers?
I am wondering about this from a cost stand point as well. I dont want to run the lighter fluid if the weight was raised due to a problem with it, but I also dont want to run the heavier fluid at the heavier expense just to drain good fluid out at 30,000 miles. The first 30,000 miles I ran the RP 75w90 it drained out with the same reddish purple color that it went in with. I also have an open diff if it matters. Any ideas or opinions are welcome.
Here are a couple shots from my 2002 manual:
It doesnt even say to use synthetic (which I will use anyway), just GL-5 Hypoid gear oil.
This is from the 2004 manual:
Here are some shots from my