RAM rear limited slip differntial

[gearhead]

Recently someone asked if I had any issues with my 2018 RAM 3500. Nope, none. Well, that has changed. Awhile back I noticed when backing out of the garage and turning with brake applied, the rear end would be jerking a little. On this last trip to Iowa and Illinois it was mostly interstate and about 65MPH in 95+F temps. When making a quick fuel stop and leaving the truck stop the rear end would jerk and grab pretty good like I had engaged 4wheel drive locked. No issue going straight down the road. Long story short I discovered the newer generation of Rams have a Torsen style limited slip rear end, no clutches. I was told that is why the rear tires grab and sometimes chirp on turns. So Mr. Gearhead here decides at 50,000 miles it may be time for a diff oil change. I got some LUCAS synthetic 75W-90 to take to my dealer. It was time for engine oil change and fuel filters anyway. All the Chrysler info I found said no additive required. So I go back and forth with the service writer about the additive. He says yes, I say no. I threw out my Senior Machinery Specialist for Shell card, he throws his Chrysler Platinum Service Writer card. OK, you're the winner. Put it in, it shouldn't hurt anyway. They did. So I bump into the mechanic that did the work and we discussed the additive. He said Chrysler got tired of paying for differential rebuilds and sent a service bulletin out to use the additive. Heck I don't know, we'll see if it helps.
If you need some sleepy time reading:
https://torsen.com/how-it-works/

[Brentw]

Funny story.
Interesting, wish they had a better picture.

Yet, it still can differentiate freely and smoothly at low torque levels, so the car is docile and easy to drive

Ya, sorta.

Dang, now I'm on a YouTube how it works binge.

[Laredo Tugger]

Thanks for the info Mr. Gearhead. I did read the article you posted, it reads like technical advertisement verses useful information.
I also have a SRW 3500 4x4 with the Aisin transmission. I just got my truck out of the shop (dealers) yesterday for replacement of the ABS pump on the brake system. Last March the same shop also replaced a electronic actuator that failed on the four wheel drive system. The service writer said I was the second ABS pump replacement within a week, I guess they saw it coming because they had the part in stock and I got the truck back the next day. Just FYI and hope you do not have these issues.
So I understand correctly, you took an additive to the dealer service center that you did not want added to your differential? I also have felt some shudder and vibration upon take off from a stop with my truck, nothing major but I will be looking into the issue. I found a service bulletin on the differential (03-001-20 ) and it recommends a complete fluid change of the differential using SAE 75W-85 HD Ram GL-5 Synthetic Axle Lubricant. The sales code for this differential is "DSA".
Did your dealer service just add the Lucas product or perform the specifications of the service bulletin? (complete fluid change) I could probably do either one myself but being a "driveline" service issue it is covered under the 5yr/60000 mile warranty.
Thanks again,
RMc

[ingram]

I also have a 2018 RAM 3500 DRW, Aisin, 4.10. My rear end failed at 4,800 miles. Horrible noise. The dealer had to rebuild it. They said the pinion angle was incorrect, I'm no mechanic, I said alright. Chewed up metal all in it. It took 32 days for them to get the parts. It has 11,000 and some change on it now, and I just started to notice the grabbing and jerking you are talking about. My last trip for the season is this weekend. It's going back in afterwards. It doesn't feel right to me and I'm getting it looked at before the warranty expires.

[Laredo Tugger]

Originally Posted by ingram

I also have a 2018 RAM 3500 DRW, Aisin, 4.10. My rear end failed at 4,800 miles. Horrible noise. The dealer had to rebuild it. They said the pinion angle was incorrect, I'm no mechanic, I said alright. Chewed up metal all in it. It took 32 days for them to get the parts. It has 11,000 and some change on it now, and I just started to notice the grabbing and jerking you are talking about. My last trip for the season is this weekend. It's going back in afterwards. It doesn't feel right to me and I'm getting it looked at before the warranty expires.

ingram,
I have close to 45K on my truck and it is the 3.73 rear end. The service bulletin should cover all of the gear ratio packages offered.
Yes, because this issue is "drivetrain" related it should be covered under warranty. My ABS pump was not covered under dealer warranty, that expired at 3yr/36000 miles, but I have an extended warranty that picked up the bill for my deductible. A $700 repair for a $100 deductible, a good day for the pocket book, few and far between these days.
Use the info in my last post for reference of the TSB. I printed a copy to show the service writer. Shouldn't be any questions.
Good luck,
RMc

[gearhead]

But wait, there's more...
...No I didn't give the service writer the additive. I was expecting none required. The dealer supplied it. It got a bit contentious about the additive. Down to.."why are you questioning me, if I tell you, you can take it to the bank." Yeah I've heard that BS before cowboy. But I like the guy and just shut up about it. Any other circumstances I would have asked to see something in writing. In my previous life we called that "Management of Change".
Here is more...somewhere in this trip the GPS/radio started going crazy. It would change stations on its own and the GPS just made no sense. So at the dealer I told the service writer to check that. I got a "let me go look at it, I might can diagnose it" He's not only a Platinum Service Writer, he is apparently clairvoyant. He looks at the screen and pronounced it DEAD. "Look at that black line across the the top of the screen, the screen is detaching from the unit". I had to get the sun reflection just right to see it. OK, this is going to be expensive. I wander around the showroom thinking about how I'm going to break this news to Betty. One of the salesmen asked what I was doing, and I explained the radio. Do you have an extended warranty? I think so, but Betty says no. So we punched it up on the computer...OH YEAH, 100,000 miles or until 2024! I don't remember what that warranty costs but it just saved me $1154 minus the $100 deductible. Radio is on order.
Ok, I'm almost finished with overhauling the fuel system on the GoDevil mud boat, New fuel hose, new throttle and cable assembly, new water separator, new fuel filter. All that's left is the oil change. I'm almost ready to run down da bayou flounder fishing. Almost Miller time.

[ingram]

Get ready to wait a while. they are backordered from China. My wife's Grand Cherokee had the same problem, 8 weeks ago. Line across the top and corners, went nuts. You can take it apart and just replace the LG screen, but also backordered everywhere. I pre-ordered 7 weeks ago. $580.00 for just the screen. She has been driving around with a hole in the dashboard. No radio, etc.

[ingram]

It's a very common problem for any Chrysler car with Uconnect 8. whatever it is.. Seems to be limited to '17 and '18 vehicles.

[gearhead]

Originally Posted by ingram

Get ready to wait a while. they are backordered from China. My wife's Grand Cherokee had the same problem, 8 weeks ago. Line across the top and corners, went nuts. You can take it apart and just replace the LG screen, but also backordered everywhere. I pre-ordered 7 weeks ago. $580.00 for just the screen. She has been driving around with a hole in the dashboard. No radio, etc.

Ah ha...you must not have a PLATINUM Service Writer. LOL My guy just called me and said my radio is in. Install scheduled for Tuesday afternoon.
Probably not the same unit.

[sourdough]

Originally Posted by gearhead

But wait, there's more...
...No I didn't give the service writer the additive. I was expecting none required. The dealer supplied it. It got a bit contentious about the additive. Down to.."why are you questioning me, if I tell you, you can take it to the bank." Yeah I've heard that BS before cowboy. But I like the guy and just shut up about it. Any other circumstances I would have asked to see something in writing. In my previous life we called that "Management of Change".
Here is more...somewhere in this trip the GPS/radio started going crazy. It would change stations on its own and the GPS just made no sense. So at the dealer I told the service writer to check that. I got a "let me go look at it, I might can diagnose it" He's not only a Platinum Service Writer, he is apparently clairvoyant. He looks at the screen and pronounced it DEAD. "Look at that black line across the the top of the screen, the screen is detaching from the unit". I had to get the sun reflection just right to see it. OK, this is going to be expensive. I wander around the showroom thinking about how I'm going to break this news to Betty. One of the salesmen asked what I was doing, and I explained the radio. Do you have an extended warranty? I think so, but Betty says no. So we punched it up on the computer...OH YEAH, 100,000 miles or until 2024! I don't remember what that warranty costs but it just saved me $1154 minus the $100 deductible. Radio is on order.
Ok, I'm almost finished with overhauling the fuel system on the GoDevil mud boat, New fuel hose, new throttle and cable assembly, new water separator, new fuel filter. All that's left is the oil change. I'm almost ready to run down da bayou flounder fishing. Almost Miller time.

Maybe the additive would have helped the radio???? Sorry Brent, just got in from the road and thought I'd make a funny, sounds like you got enough "stuff" going on.

[gearhead]

Originally Posted by sourdough

Maybe the additive would have helped the radio???? Sorry Brent, just got in from the road and thought I'd make a funny, sounds like you got enough "stuff" going on.

You probably know how it goes....all summer it's hottern 9 kinds of Hades and I tell myself...I'll do that the first day it cools off. Today is that day...we got the same cool front I assume everyone else did. It was down to a frigid 66F this morning and the humidity was blown back where it came from...the Gulf of Mexico. Tomorrow morning forecast is 58F. I'm going to mow in a bit and that will be it for today.
You get those disc brakes broke in?

[sourdough]

Originally Posted by gearhead

You probably know how it goes....all summer it's hottern 9 kinds of Hades and I tell myself...I'll do that the first day it cools off. Today is that day...we got the same cool front I assume everyone else did. It was down to a frigid 66F this morning and the humidity was blown back where it came from...the Gulf of Mexico. Tomorrow morning forecast is 58F. I'm going to mow in a bit and that will be it for today.
You get those disc brakes broke in?

Don't know that they're broke in good yet, about 1000 miles. In about a month we'll be heading to FL so they'll get a good workout them. Really happy with them.

We had the same front hit here. Knew it was coming but didn't really think about how cool it would feel. The John Deere people were here at 7:30 to pick up my little tractor for servicing and when I walked out I was really surprised. Guess since it's the first day of fall it was right on time.

[Laredo Tugger]

gearhead partial quote: "But wait, there's more...
...No I didn't give the service writer the additive. I was expecting none required. The dealer supplied it. It got a bit contentious about the additive. Down to.."why are you questioning me, if I tell you, you can take it to the bank." Yeah I've heard that BS before cowboy. But I like the guy and just shut up about it. Any other circumstances I would have asked to see something in writing. In my previous life we called that "Management of Change".

OK Brent, I read that you took the additive to the dealership (not the case) to be used in a differential oil change but evidently they pumped in their own "additive".
Reviewing the TSB it recommends a differential oil change and refilling with a SAE 75W-85 Ram GL-5 Synthectic Axle Lubricant Part #68210057AB.
So (if you know) is the remedy to the rear differential shudders and vibrations while turning at low speeds the "additive" (available at the dealership) or a complete differential oil change as recommended in the TSB? Or are we talking about the same thing here?
I will also see what my service dealership recommends.
Thanks,
RMc

[gearhead]

I've been busier than a cat covering up feces here lately but..
I asked my Platinum Service Writer about pulling the diff cover vs. draining vs. sucking it out. He said if it has a drain plug they will use it, otherwise they pull the pumpkin. I'm 99.9% sure I don't have a drain plug. I have a Big Wig anti sway bar that I thought would make pulling the cover a PITA, thus the dealer.
Setting up a gearbox is easy, but then it isn't. I've never done an auto diff, just industrial, and usually herringbone gears or straight cuts. Backlash and bluing the engagement pattern is usually the failure point. We had a mighty fine gearbox man at work but if not him, it was a trusted vendor.

[jasin1]

Inboard boat propellers often times get setup wrong because the installer doesn’t take the time to use the blue compound on the tapered shaft…you have a prop that seems like it’s installed properly…you put some prussian blue or equivalent on the shaft and find out the prop and shaft tapers don’t match completely…have to take the high spots off carefully with Emory cloth and get a much better fit…that’s as far as I get with machining…I’ve never been good with machining close tolerances or gear setup so I’ve always avoided it …my father in law was a master machinist and he was amazing…sure do miss that guy…thanks for the heads up on what to look for

[jasin1]

Damn that’s pretty impressive ( post #19)

[gearhead]

Originally Posted by jasin1

Damn that’s pretty impressive ( post #19)

Like those machinery pics? Here's some compressors pushing nat gas up north from south Texas. V-12 Waukesha engine driving Ariel compressor. Installed 12 of these on a 100,000 acre ranch about 10 miles from the Rio Grande.

[jasin1]

Originally Posted by gearhead

Like those machinery pics? Here's some compressors pushing nat gas up north from south Texas. V-12 Waukesha engine driving Ariel compressor. Installed 12 of these on a 100,000 acre ranch about 10 miles from the Rio Grande.

Well I wouldn’t want to pay that crane bill …guess they paid two cranes for at least a day a piece…seems like a unbalanced load but I would think one crane could do that job

Edit: I’m guessing the contractor owns the cranes

[Laredo Tugger]

The only experience I have meshing gears was with a motorcycle gear case that I split years ago. So, I am happy to let the dealer pull the "fill" plug and inspect it. If they deem further disassembly is required, they can do it under warranty.
The TSB instructions show that removing four bolts allows you to move the sway bar out of the way, never done it so I won't say it's easy. My service writer said they use a pump for their differential oil changes unless the "fill" plug (on our model trucks) shows excessive shavings, then they will remove the cover. I do not have a drain plug either.
RMc

[gearhead]

Originally Posted by Laredo Tugger

The only experience I have meshing gears was with a motorcycle gear case that I split years ago. So, I am happy to let the dealer pull the "fill" plug and inspect it. If they deem further disassembly is required, they can do it under warranty.
The TSB instructions show that removing four bolts allows you to move the sway bar out of the way, never done it so I won't say it's easy. My service writer said they use a pump for their differential oil changes unless the "fill" plug (on our model trucks) shows excessive shavings, then they will remove the cover. I do not have a drain plug either.
RMc

My sway bar is an aftermarket monster, Hellwig Big Wig. It's big and pretty close to the diff cover.