pinarello57

2017 RAM 3/4 long box

I get a shutter under unloaded take off which seems greater when hot, I.E. totally smooth when cold. This is under a normal light acceleration take off. Is this drive line alignment, torque converter, engine etc? My 2015 3500 would do this seldom when unloaded but was not temperature sensitive, this is worse or more than before. Both have the same transmission 68RFE. Both trucks were lifted 2" front end with shock extension but both operated exactly the same since new and the lift did not change a thing.

Desert5600

Must still be on warranty. Take it to the dealer.

pinarello57

Yes, that's where it's going on Tuesday

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My 12 does it. I replaced the u joints, carrier is fine. I just had a drive train shop look at it and they said they can't find an issue, other than he thinks it may be as the drive train loads up, it moves, and they drive shaft shimmy's itself longer. He has an 11 and says his does the same thing and its seems better if he lubes the splines in the driveshaft. The official fix is a one piece drive shaft, which to me would support what this guy says. Also to me, just the nature of the entire length of the drive train from front diff to rear diff, that includes 5 u joints and three spline sets to grow and shrink so its just the nature of things. One may say that the front driveshaft is not in play because it's in two wheel drive, but it still is spinning and stretching. I'm sure free spin hubs along with that one piece driveshaft would help. But your talking big dollars. So....any other comments or different views welcome. I'm still at "I think" on all of this.

pinarello57

It goes into the dealer today. This truck, the 2017 2500 is new so we'll see what they say. I find it interesting that it mainly loads up in rush hour traffic, hotter and slower type acceleration. The shop foreman did say the trucks would shutter some but find it goes away if the truck is loaded (weight in truck or pulling), haven't had a big load yet. Interesting, my 2015 3500 doesn't shutter at all (loaded or not) other than rarely so they can be made to work properly!!!

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Please report back if they fix it and what they did/tried.

pinarello57

We drove another truck, the only LB in stock was a 3500. The shutter is in all the trucks at startup, just greater in mine. On mine the engine as well modulates with the shutter but not on the 3500 we compared. SO, it was elevated to tech support TBD. Tech support should get back soon so I will update then. We unfortunately did not have a 2500 LB to compare yet, the only one was in transit.

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I've been thinking it's just what they do and there really is no fix

pinarello57

After reading tons of blogs, the consensus seems to be the shutter worsens under load, it is "not" necessarily axle wrap, it is "not" immune or worsen from or to 3500 vs 2500, shimming the carrier bearing (I.E. drive line alignment) may help, relieving stiff u-joints and greasing splines may help, not all trucks have it to this degree and they can be made more drive-able like my 3500 and the truck we tested at the dealership... This takes me back to my original thought, the drive train is under load and releasing the drive train alignment pressure on the engine, transmission and carrier bearing (drive line), then allow it to reset without a load or twist on the mounts, may relieve some of the shudder? Another words, put truck on drive on rack so the suspension is loaded, support drive train (jacks) and loosen all mounting bolts, reset drive train on frame unsprung and re-tighten mounts including carrier bearing mount. It was mentioned numerous times that shimming the carrier bearing may also help with the drive line alignment? This is all given the u-joints and carrier are good, they are new in my case so they should be but at this point who knows.


The rush hour drive-ability and heat vs cold operation, worsening when warm, adds logicality to this conclusion.

In any case from the blogs, the truck is fixable if one has sharp enough techs and willing to support the effort, I.E. it can be corrected.

chrism69

I was pulling my 5th wheel the past two weeks and noticed shutter under load take off I also have the 68 rfe. I think it is shudder or shutter, I was stopped after pulling for a few hrs and went to take off and felt vibration in drivers seat and through the whole truck. Never noticed it when unloaded my truck just turned 18 k. I also noticed on hills in tow haul mode a slight delay with the trans unloaded. Going to make an appt. w/ the dealer.

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How think are the shim/shims in the shim kit? I can take a strap of metal and drill two holes myself.

pinarello57

From what I read the recommendation is 1/4" per 1" lift. So in my case it would be 1/2". Only issue is my 2500 shuttered before the lift. I did the same 2" front lift on my 3500 and it did not shutter before or after the lift. Bottom line, what's to loose, I would try the 1/2" (in my case) but still waiting to hear from the dealer as they escalated it to RAM tech support to see what they recommend, if anything.

1-2-3

I forgot all about the shim kits. I'm going to grab a strap of 1-1/2 wide x 1/4 thick steel (looks like about $9) and a couple of 2-1/2 inch bolts with lock nuts at Lowe's and try a shim this weekend. I can make several from a 3 foot bar. I'll try 1/4" at a time. I have the front lifted 2" with a level kit but it's been doing this since before that. I will report back with results.

pinarello57

From what I understand use as few as possible to alleviate or minimize the shutter on take off. Using too many (dropping the carrier bearing too much) will aggravate the shutter under a heavy load so there is a compromise.

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So............my curiosity got the best of me. On the way home I stopped at Lowes. Got a 1.5 x 36 x .25 steel flat bar, ($11.95) and two M10 x 1.5 x 50 x 40 mm bolts. The longest of the two that was threaded the entire length. ($1.95)

I cut an 8 inch bar, then drilled two 1/2 inch holes 6 and 3/4 apart. 3 and 3/8 from center for each. I dropped one factory bolt out, then loosened the other till the bearing unit dropped enough to slip the shim in, installed a new bolt then swapped out the other bolt. Cinched them both down. Never dropped the shaft down.

Here's the crazy part.....I think it's fixed. For real. I went on a drive and couldn't make it shudder no matter what I did. Mine always did it regardless of cold morning or hot afternoon, load or no load.

Holy cow. I wished I would have done this a year ago. I don't think I am going to add a second shim.