2nd Gen Non-Engine/Transmission rear diff fluid

[Mike C]

i have searched the site but cant figure why people are not using sae 90 gear oil in rear. what advantages are there to not using the sae 90. is it better to use something other then the sae 90. i tow maybe once a month nothing real heavy 5000 to 8000 lbs. at most

 

[pwr2tow]

Originally posted by mike c

i have searched the site but cant figure why people are not using sae 90 gear oil in rear. what advantages are there to not using the sae 90. is it better to use something other then the sae 90. i tow maybe once a month nothing real heavy 5000 to 8000 lbs. at most

Multi-weight gear oils should give a little better fuel mileage ( I don't think you can really measure the increase, too little). Some use multi-weight oils because of climate changes ( I'am in that catagory). Multi-weight oils in synthetic should give better mileage, better wear properties, better fluid flow in cold temperatures, and if you don't change often it is better for extended drains (you should always change according to your manual).



Ron

 

[illflem]

I've always used 80w-90 dino oil in my differentials and imagine most Ram owners also do, just not on this website. Over 300k combined miles on my two Rams. May be an oddball here but it works just fine for me especially when I buy and pump from a 5 ga tub into many different gearboxes on vehicles and farm equipment.

Heck if it's approved for 750,000-mile extended warranty service in heavy truck axles and 500,000 miles initial fill and service interval in Dana rearends that's good enough for me especially since I'm going to change it before then.



I pay $23 for 5 gallons Chevron ESI 80w-90



You might also consider Chevron 75w-140 if you tow heavy.



"Chevron Delo Gear Lubricant ESI SAE 80W-90 and 75w-140 are the first nonsynthetic gear oils approved for the 750,000 extended warranty program of Dana Spicer heavy duty axles and is an approved lubricant for drive axles under the Eaton Roadranger E500™ Extended Warranty Program. Chevron Delo Gear Lubricants ESI is also approved for the extended drain specifications of both Meritor® and Mack. "

 

[Gary - K7GLD]

If it wasn't for the limited-slip differential unit in my differential, I'd probably use a top rated single weight synthetic - but I sorta suspect that uniform hot/cold function of the LS relies upon the stability of the multi-weights for proper and reliable operation...

 

[jelag]

My 01 3500 has a little over 40K and I decided to replace both the gear oil in the transmission and the differential oil with synthetic oils... .



It took some looking but I found a supplier with both the gl4 and gl5 on the shelf in synthetic... . I was going to let my lube center do it for me but they wanted $80 a box to do it... .....



I was amazed at all the dirt in both boxes and the layer of metal on the magnets..... I also added a temp gauge to the manual transmission as I had the side cover off... ...



Both the GL4 and the GL5 are light in color and texture over the stock oils... .



We use this truck to tow up to 22K on a custom trailer and felt we needed to follow the owners manual suggestion to move to synthetic oil.....



Jim

 

[RustyJC]

Originally posted by mike c

i have searched the site but cant figure why people are not using sae 90 gear oil in rear.

The short answer is that my owner's manual recommends 75W-140 synthetic for heavy towing applications. Since we tow a 36' triple slide 5ver (10,380 GVW/10,500 GVWR; 21,180 GCW/21,500 GCWR), I'm using Royal Purple 85W-140 synthetic with no supplemental Mopar friction modifier for the limited slip, and it's working fine.



I did the same thing for my 1996 V-10 3500 that pulled our previous 30' and our current 36' 5ver.



Rusty