4th Gen Rear Diff Fluid Discrepancy?

Wild one

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They had 4 75/90 and 3 75/85 left at JB Powercenter on Saturday, still had half of one on the shelf at home. Cheaper than Amazon. They had no 110 or 140.View attachment 496816
Mopac on 16th usually has a better stock pile of Redline then JB's does,but they aren't open on Sundays like JB's is.
JB's is also Amazon.ca's supplier,lol
 

Wild one

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Mopac always has a much better selection. JB is much closer.
Ever since big Fino left JB's i don't go there as often,as i could always get a deal through him,now i'd rather deal with Bill at Mopac,but you're right JB's is closer to Airdrie. Supposedly Lordco carries Redline,but i've never dealt with them to check out their selection of Redline,and they're even farther away then Mopac
 

Wild one

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Wild one have you ever used the shockproof?
If you're referring to this stuff,no i haven't as they reconmend it for racing diffs under moderate loads,and that kind of scares me a bit.

 

airrecon

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To start off I live in a small town where everyone knows everyone, I am good friends with the salesman whom sold me the truck and he is great friends with the owner. I never get up sold or even try to, everyone at the dealership knows me etc.



I hit 100,000km and my rear diff fluid looks new and I wanted to change it, I went and purchased 75w140 as that’s what the manual states to use, I went over to visit the salesman (as he is a friend of ours) and my child poses for dealership pictures when the new owners don’t want to, it started as a joke and has taken off he asked if I called the dealer to check the price, I stated no because the dealer is always more expensive. He talked with the parts manager and they ran my vin, as per my vin my rear takes 75w90 and if my truck was in getting work done and they needed to add fluid it would be 75w90. So this got me to digging, the same owner owns a tirecraft (a tire shop that also does mechanic work) and has their own software for instructions on fluids, mechanical work, the time jobs should take and the amounts of fluids needed in all different makes and models. According to their system by inputting my make and model it tells them to use 75w90 and 2.2 litres.



Now I am confused, the manual calls for 75w140 but all other places I’ve contacted including the dealer call for 75w90 I don’t have the limited slip and just the “conventional rear end” 3.21 gears which fluid should I use? Or just leave it alone?
 

airrecon

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Why can't you just believe the Ram manual that was written by the engineers that designed the vehicle?
 

JB Weld

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I'm running Valvoline 80w-90 without friction modifier in my '19 1500 Classic. But this is because I installed a Tru Trac differential. Works great in all temperatures and loads so far.
 
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