2017 Ram 1500 3.92 LSD Fluid

[grizzstang]

I tow my travel trailer with mine and actually use it as a truck so I will stick with the 75W-140 in the rear diff too.

IMO opinion most dealers can't find their ass with both hands so their recommendations mean nothing to me.

 

[slickracer]

My 2018 calls for 75W-90 in the rear.

 

[Burla]

My 2018 calls for 75W-90 in the rear.

It is is a 1500 is takes 140 weight.

Page 603 of owners manual...

Front Axle – 1500 Four-Wheel Drive Models We recommend you use Mopar GL-5 Synthetic Axle Lubricant SAE 75W-85.

Rear Axle – 1500 Models We recommend you use Mopar Synthetic Gear Lubricant SAE 75W-140 (MS-8985). Limited-Slip Rear Axles require the addition of 5 oz. (148 ml) Mopar Limited Slip Additive (MS-10111). Front and Rear Axle –

2500/3500 Models We recommend you use SAE 75W-85 HD Ram GL-5 Synthetic Axle Lubricant. L

 

[slickracer]

It is is a 1500 is takes 140 weight.

Page 603 of owners manual...

Front Axle – 1500 Four-Wheel Drive Models We recommend you use Mopar GL-5 Synthetic Axle Lubricant SAE 75W-85.

Rear Axle – 1500 Models We recommend you use Mopar Synthetic Gear Lubricant SAE 75W-140 (MS-8985). Limited-Slip Rear Axles require the addition of 5 oz. (148 ml) Mopar Limited Slip Additive (MS-10111). Front and Rear Axle –

2500/3500 Models We recommend you use SAE 75W-85 HD Ram GL-5 Synthetic Axle Lubricant. L

My Owners Manual states 75W-90. Believe what you want but it's there in black and white.

 

[Burla]

That is your owners manual online in black and white. You could put cat **** in there for all I care, it's nothing to me.

 

[Ridgerunner665]

Mine is a 2018 too....3.92 limited slip, manual says put 140 weight in it.

Sent from my SM-G960U using Tapatalk

 

[Hsargent21]

I asked Ram Cares and the confirmed 75-90. I then asked if I needed the LSD additive. They said to do whatever the dealership said.

 

[Tim Garceau]

Anyone that questions a lighter weight rear gear oil is putzing around unloaded to the grocery store anyway, so the water will manage fine.

Amsoil makes a 75W110 if you tuck it between your legs sometimes.

 

[Burla]

Operating visc 16- 75W90
Operating visc 21- 75W110
Operating visc 27- 75W140

Basically you will be putting a 40 weight engine oil in your rear diff, and as you see there is a middle choice. I think the question you should be asking is why despite fuel economy goals does the manu want 140 weight, I'd pm tach tech.

 

[slickracer]

I asked Ram Cares and the confirmed 75-90. I then asked if I needed the LSD additive. They said to do whatever the dealership said.

I guess Burla will be calling them to tell them they are full of crap...

 

[slickracer]

That is your owners manual online in black and white. You could put cat **** in there for all I care, it's nothing to me.

Very helpful, I guess posts like this are why you got banned over at Bob`s

 

[Burla]

Very helpful, I guess posts like this are why you got banned over at Bob`s

Yeah, I'm not liked around here much either, except for the 100 guys who trusted me enough to run my lubrication strategy that BITOG scoffed at and single handedly killed their hemi tick, LMAO. You cannot survive BITOG when you are responsible for such a redline oil success story, read every single redline post overthere. Know who runs the forum over there, so much hate for the one product that uses heavy base oils? Doesn't make sense for an oil forum, til you look at who pays the bills and who supports the mods. Bother yourself to read the oil stories here and what it has done for 100 or so Ramily, then learn how to behave. BITOG "oil guys", LMAO.

 

[slickracer]

Yeah, I'm not liked around here much either, except for the 100 guys who trusted me enough to run my lubrication strategy that BITOG scoffed at and single handedly killed their hemi tick, LMAO. You cannot survive BITOG when you are responsible for such a redline oil success story, read every single redline post overthere. Know who runs the forum over there, so much hate for the one product that uses heavy base oils? Doesn't make sense for an oil forum, til you look at who pays the bills and who supports the mods. Bother yourself to read the oil stories here and what it has done for 100 or so Ramily, then learn how to behave. BITOG "oil guys", LMAO.

You practically called me a liar so see attached.

 

[Burla]

I never doubted you and never called you anything, I simply posted your 2018 manual online. Don't blame me for what the 2018 online manual says, I didn't write it.

I saw the other manual posted as well that verified your position. Ram apparently changed the spec sometime in 2018 as 5 gens are calling for 90 weight as well. If it were me, I'd find out why they changed the spec, especially those with pre heated diffs. Now diffs run hotter, and they call for thinner oil, and fca thinks this was smart? I hoped they actually changed the diff to accept the thinner fluid.

 

[Burla]

Alpar

The thermal management system has expanded beyond using heated coolant to warm transmission fluid and engine oil, now running hot coolant through the rear axle lubricant on RWD trucks. First priority goes to the passengers, depending on the HVAC setting; but then a valve sends coolant to the rear axle, warming the gear oil so the axle has less resistance and is more durable (especially during cold-weather hauling and towing).

So fca is "fixing" a problem, cold temp hauling, but at what cost? Pre heating diff fluid and using thinner fluid in the same differential? If I had one of these vehicles, I would ask a mechanic that works at fca exactly what changed in the diff.

So I wonder if once the diff is hot does it then cool the diff? If so it makes sense, which is why I don't think they do it, they are not big on making sense.

 

[Tim Garceau]

The thermal management never made it later than paper concept. They were hyping it up on several prelaunch sites, no way was it cost effective.

 

[Burla]

The thermal management never made it later than paper concept. They were hyping it up on several prelaunch sites, no way was it cost effective.

That actually is funny, I wonder if as a way to mitigate that failure they simply have guys run thinner fluid, lmao. Wow, crazy if that is what happened. That would solve the issue of towing with cold fluid, but could lead to issues if there was a reason for the 140 weight in the first place. Really makes the strategy of splitting the baby a viable option, and at least go 110w.

 

[Burla]

Call the same dealer and tell him you have a 2010 ram and what oil weight goes in the diff.

 

[Hootbro]

Late model Ford, GM and even Toyota half ton trucks all spec similar lower gear oil weight grades for their differentials. If RAM has been factory filling 1500's with these lower weight grade gear oils since 2017, one would think the internet would be littered with reports of catastrophic failed differentials if these lower weight grade gear oils were not doing the job.

In my opinion, I think sticking to a quality full synthetic gear lube is going to be more important than worry about perception of 90 vs. 140 weight grade gear lube.

 

[pacofortacos]

IMO 75-90 worked fine for decades, but I like a quality 75-90 and changes every couple of years for it to give years of trouble free operation.
Let's face it, the 9.25 has been around for an eternity.
This go round is the first time since the factory fill that I have put 75-140 (Valvoline synthetic) in it and that's because I had the dealer do it for the lifetime warranty. It will stay in for the next trip and I will go back to a lighter oil in Redline - my preferred gear lube.

I have run 75-90 and 75 -110 and change it every 2 years max, often less.

I have run Redline 75-90 in the 9.25 rears since 2001 and never had any issue - and I tow yearly and at high speed (70+ mph) for 2800 miles in a week. It definitely tests the rear differential.