Shudder/vibration at low speed turning or backing

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jason Horn

Junior Member
Joined
May 29, 2020
Posts
7
Reaction score
1
Location
Bakersfield
Ram Year
2018
Engine
Hemi 6.4
Has anyone figured out what this is? I have a 2017 Ram 2500 5.7 Tradesman. I thought it was tires at first but that can’t be it. Only does it when starting to pull out or back up from park. It lasts mere seconds (1-2 seconds at most). Here lately it’s been doing it more. I believe I have the factory gears and don’t have the clutch. I checked my rear end and the fluid was full. I did have minor metal flakes on the magnet.

Friction modifier additive. Evidently it brakes down quicker then the recommended fluid change. I had the same problem.
 
Last edited:

Jason Horn

Junior Member
Joined
May 29, 2020
Posts
7
Reaction score
1
Location
Bakersfield
Ram Year
2018
Engine
Hemi 6.4
Friction modifier additive. Evidently it brakes down quicker then the recommended fluid change. I had the same problem.
 

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
It went away after the fluid change, but has started back up again. He said there will be some normal noise due to how the limited slip unit is constructed. But I haven't had a chance to look into it further. It almost sounds like a brake grabbing at the same time. I've wandered if it is something in my brake system. Maybe a caliper dragging after coming to a stop or something.

Anyway, it was still worth the gear change! I love my truck even more now.

I pulled the camper this weekend & it made the shudder more noticeable with all of the weight on it & behind it. I keep seeing other posts stating that it's the friction modifier. I didn't think our diffs required friction modifier. I am getting ready to do a fluid change with Amsoil Severe Gear. Maybe this will resolve the issue.
 

62Blazer

Senior Member
Joined
Dec 11, 2019
Posts
1,069
Reaction score
1,256
Location
Midwest
Ram Year
2016
Engine
6.4
My '16 PW with 30k miles has a mild shudder during slow speed turns at times. As mentioned above the factory limited slip diff in the HD trucks is basically a gear to gear torsen type setup and shouldn't require a friction modifier (there is no "friction" going on like a clutch pack type limited slip). I would be more suspect that simply fresh fluid was helping get rid of the shudder and it doesn't have anything to do with the friction modifier.
 

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
My '16 PW with 30k miles has a mild shudder during slow speed turns at times. As mentioned above the factory limited slip diff in the HD trucks is basically a gear to gear torsen type setup and shouldn't require a friction modifier (there is no "friction" going on like a clutch pack type limited slip). I would be more suspect that simply fresh fluid was helping get rid of the shudder and it doesn't have anything to do with the friction modifier.

That is what I thought... no friction modifier needed.
 

Jason Horn

Junior Member
Joined
May 29, 2020
Posts
7
Reaction score
1
Location
Bakersfield
Ram Year
2018
Engine
Hemi 6.4
you guys realize the friction modifier is cheap and harmless to a rearend if not needed? i get that you don't understand why or that it does not make sense but what would be the harm of squeezing in a tube to see if it resolves the problem as per the mfgr recommendations? My dealership showed me the literature from the mfgr that clearly says add (part number) friction modifier.
 

Travelin Ram

Senior Member
Joined
Jan 8, 2020
Posts
1,840
Reaction score
2,982
Location
Somewhere in NA. Probably. We travel a lot.
Ram Year
2022
Engine
6.4
I wouldn’t say friction modifier is harmless if you’re counting on your helical (Torsen type) LSD to do the job it’s designed for and transfer torque to the wheel with greater traction.

These devices are designed for a specific amount of torque bias using a specific lube with a known coefficient of friction. I wonder how many of these cases involving gear swaps are because the installer used oil recommended by the gear maker which may differ from the AAM recommendation for the LSD. Or a maintenance change was done and the wrong oil used.

There’s also a case to be made for replacement of the factory lube as soon as break in is done. Almost nobody does it, but you will find plenty of metal glitter if you do.
 

Firetruck41

Senior Member
Military
Joined
Jul 4, 2019
Posts
383
Reaction score
400
Location
Washington State
Ram Year
2010
Engine
2500 Mega Cab Hemi 5.7
My 2010 has done the same since I bought it last summer. It seems to be the LSD. As mentioned, it doesn't take any friction modifier. In my search I have seen no OEM literature that advises friction modifier for our LSD, in fact it says that it does not take friction modifier.

With the OP's new gears, it makes it easier to activate the LSD than when he was OEM.

Screenshot_20200612-055320_Drive.jpg Screenshot_20200612-055414_Drive.jpg
 

62Blazer

Senior Member
Joined
Dec 11, 2019
Posts
1,069
Reaction score
1,256
Location
Midwest
Ram Year
2016
Engine
6.4
you guys realize the friction modifier is cheap and harmless to a rearend if not needed? i get that you don't understand why or that it does not make sense but what would be the harm of squeezing in a tube to see if it resolves the problem as per the mfgr recommendations? My dealership showed me the literature from the mfgr that clearly says add (part number) friction modifier.
I would like to see a copy of that literature. Also make sure that this was not for the 1500 series trucks that have a different differential and do require friction modifier.
 

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
I would like to see a copy of that literature. Also make sure that this was not for the 1500 series trucks that have a different differential and do require friction modifier.

Yeah firetruck's posts pretty well sums it up.
 

Travelin Ram

Senior Member
Joined
Jan 8, 2020
Posts
1,840
Reaction score
2,982
Location
Somewhere in NA. Probably. We travel a lot.
Ram Year
2022
Engine
6.4
It’s interesting that I experienced this myself just a couple of days ago for the first time. Reversing a cold diff while turning and a definite groan / shudder from the LSD. I say interesting because I’ve had 4 HD Rams with this diff and this is a first for me. This truck has 6k miles and the fluid has been changed after break in.

Makes me wonder what’s different vs the previous trucks. Or if it’s just random luck.

PS a point of clarification- my current PW has the diff with the combo helical LSD + E locker; previous 3 had the helical only. AFAIK it’s the same design on the LSD but there’s likely some difference in internal parts to make room for the locker parts.
 
Last edited:
OP
OP
Mountaineer83

Mountaineer83

Senior Member
Joined
Jun 30, 2016
Posts
290
Reaction score
218
Location
Charleston, WV
Ram Year
2016
Engine
Hemi 6.4
I will be towing my 5th wheel this weekend and figure it will be really noticeable with the weight. But I just haven't had time to check it out myself. I may do another fluid change in the near future myself and refill with the factory spec'd fluids.

When he did my break in fluid change after the gear swap he said everything looked perfect.
 

SeppW

Senior Member
Military
Joined
Jan 19, 2020
Posts
484
Reaction score
299
Location
Northern VA
Ram Year
2016
Engine
Hemi 6.4L
I have experienced this well. I assume the truck is pushing the front wheels forward even when the steer axle wheels are turned to lock or near lock. Goes away after increasing speed and steering recenters. Doesn't happen often, but it does occur.
 
OP
OP
Mountaineer83

Mountaineer83

Senior Member
Joined
Jun 30, 2016
Posts
290
Reaction score
218
Location
Charleston, WV
Ram Year
2016
Engine
Hemi 6.4
I have experienced this well. I assume the truck is pushing the front wheels forward even when the steer axle wheels are turned to lock or near lock. Goes away after increasing speed and steering recenters. Doesn't happen often, but it does occur.


Mine goes away after turning back straight as well and after gaining some speed. It's actually quiet loud if I am backing into my driveway. Sounds as if something will eventually snap!
 

Jason Horn

Junior Member
Joined
May 29, 2020
Posts
7
Reaction score
1
Location
Bakersfield
Ram Year
2018
Engine
Hemi 6.4
I would like to see a copy of that literature. Also make sure that this was not for the 1500 series trucks that have a different differential and do require friction modifier.
just got my truck back today from Ram, what a joke. anyways it no longer vibrates/shudders they changed the fluid and added required friction modifier. its a power wagon which has LSD in front and rear, I asked for a copy of literature and he said they don't have printed copies. I will look in my book this weekend. the thing that ****** me off is the online book says no regular service required for front or rear diff, his computer says power wagon requires service at 30k for both?
 
OP
OP
Mountaineer83

Mountaineer83

Senior Member
Joined
Jun 30, 2016
Posts
290
Reaction score
218
Location
Charleston, WV
Ram Year
2016
Engine
Hemi 6.4
It is interesting that the dealerships are recommending the friction modifier. I started to buy a tube yesterday but didnt. I may add it and see if it goes away. I will be towing my 5th wheel again next weekend. It was really bad as mentioned while towing.
 

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
I just changed my fluid this weekend. I was surprised that the oil looked dirty! I re-geared in January, so there is only 6 months on this oil. Everything (other than the oil) looked fine in there. Small amount of metallic on the magnet which is expected with the break in. Surely the installer didn't put my old oil back in? They told me they put in Royal Purple Synthetic. This is not a fly by night shop. They have been in business for 56 years. I will be pulling the 5th wheel this week so I will see if the new oil (Amsoil Severe Gear) takes out the small amount of shudder when turning.
 

Jason Horn

Junior Member
Joined
May 29, 2020
Posts
7
Reaction score
1
Location
Bakersfield
Ram Year
2018
Engine
Hemi 6.4
It is interesting that the dealerships are recommending the friction modifier. I started to buy a tube yesterday but didnt. I may add it and see if it goes away. I will be towing my 5th wheel again next weekend. It was really bad as mentioned while towing.
I guess there is some issues with the standard manual which clearly says friction modifier not required, it also says regular service not required. if you have a power wagon it has LSD then regular maintenance at every 30k is what I am told is required to prevent the shudder.
 
OP
OP
Mountaineer83

Mountaineer83

Senior Member
Joined
Jun 30, 2016
Posts
290
Reaction score
218
Location
Charleston, WV
Ram Year
2016
Engine
Hemi 6.4
I just changed my fluid this weekend. I was surprised that the oil looked dirty! I re-geared in January, so there is only 6 months on this oil. Everything (other than the oil) looked fine in there. Small amount of metallic on the magnet which is expected with the break in. Surely the installer didn't put my old oil back in? They told me they put in Royal Purple Synthetic. This is not a fly by night shop. They have been in business for 56 years. I will be pulling the 5th wheel this week so I will see if the new oil (Amsoil Severe Gear) takes out the small amount of shudder when turning.


When my shop that installed my gear did my break-in oil change it went away. Then it cam back some time afterward and as you mentioned, gets worse with the 5th wheel weight added to the truck.

I am towing again this weekend and I am tempted to add the friction modifier and see if it helps. I called my shop but they are on vacation this week and are closed.
 
OP
OP
Mountaineer83

Mountaineer83

Senior Member
Joined
Jun 30, 2016
Posts
290
Reaction score
218
Location
Charleston, WV
Ram Year
2016
Engine
Hemi 6.4
I guess there is some issues with the standard manual which clearly says friction modifier not required, it also says regular service not required. if you have a power wagon it has LSD then regular maintenance at every 30k is what I am told is required to prevent the shudder.

Looked up to 2019 manual. Everything has been addressed in it. If severe duty or towing, change the gear oil every 20k miles. It also mentions shuddering or vibration may be felt when turning on concrete or hard surfaces. It also says to add friction modifier now for limited slip axles.

Screenshot_20200630-155542_Gallery.jpg Screenshot_20200630-155554_Gallery.jpg Screenshot_20200630-155620_Gallery.jpg
 
Last edited:
Top