Drive Line Vibration at Launch

[DSorenson]

I'm looking for a bit of guidance with regard to a persistent problem I am having with the drive line on my 2003 Ram 3500 (long box, crew cab). Last spring I began to notice a vibration at launch, particularly when turning (e. g. a right or left turn from a stop light). Per suggestions on numerous posts here I found that the rubber mounting surrounding the carrier bearing had failed. I replaced the bearing which improved matters, but did not eliminate the problem. Subsequently I shimmed the bearing down per the shop manual, and comments here, which didn't seem to help much at all. I then replaced all three U-joints which again didn't eliminate the problem. Now I'm wondering if there the problem has something to do with the spline connection between the two shaft sections - as in the possibility that the spline sections are no longer sliding past one another smoothly and are sticking or binding at slower rotational speeds.



The problem is only evident at slow speed (below 10 MPH) while turning and particularly evident when backing up a small grade and turning. The greater the load the worse the vibration (pulled my 5th wheel this weekend and the problem is definitely worse).



The truck is a 2003, 3500 with an automatic, long bed and extended cab with single wheel set rear axle.



Thanks in advanced for any advice!



Don

 

[JLandry]

Don,



What exactly does the vibration feel like and how did you conclude it was the driveshaft?



I ask because you mention it's more prevalent when turning, and I wouldn't think turning should exacerbate a driveshaft problem on way or the other. Instead, maybe it's a differential problem (such as the limited slip clutch) or a front driveline issue (assume your truck is 4WD). I suppose it could also be a front hub bearing problem.



It might be worth going to a good axle shop to see what they think could be the problem.



Please keep us posted on what you find out.



John L.

 

[DSorenson]

John,

My focus on the drive shaft has been based on three items, related posts here on TDR, the fact that the drive shaft carrier bearing rubber mounting disintegrated (suggesting excessive shaft vibration) and commentary in the Dodge shop manual regarding the problem, see quote below.

CENTER BEARING
Launch shudder is a vibration that occurs at first
acceleration from a stop. Shudder vibration usually
peaks at the engines highest torque output. Shudder
is a symptom associated with vehicles using a twopiece
propeller shaft. To decrease shudder, lower the
center bearing in 1/8 inch increments. Use shim
stock or fabricated plates. Plate stock must be used
to maintain compression of the rubber insulator
around the bearing. Do not use washers. Replace the
original bolts with the appropriate increased length
bolts.

Glancing at the shop manual it doesn't look like these rear ends have a limited slip clutch.

The only explanation that I can think of as to why turning makes the problem worse is that truck chassis twists or flexes slightly forcing the drive shaft to accommodate the changing alignment.

Don

Don

 

[WOT]

there is a one piece drive shaft available (used in 2008+). there are many posts about it resolving shudder and vibrations.

 

[JLandry]

Don,



I'm familiar with those entries in the shop manual.



Suspecting the driveshaft doesn't seem unreasonable at first, but in light of the vibration getting worse in a turn seems to point to something else. I'm skeptical any sort of frame flexing is somehow contributing to the problem. If it was, this would be a common problem you would have read about here.



The fact that you've done everything you can reasonably do to the driveshaft (short of replacing it) and the problem is still there would further tend to point toward some other cause in my mind.



My 2001 2wd came from the factory with a Trac-Loc limited-slip rear end... I think that's a fairly common option on these trucks. You might check the build sheet on yours. FYI, at 87,000 miles I had the axle ratio changed on my truck and the Trac-Loc clutches were found to be completely shot at that point so I had it rebuilt. The first time I changed the differential oil after that rebuild I cheaped-out and used a tube of aftermarket limited-slip additive instead of the official Mopar stuff. Within a couple of hundred miles that Trac-Loc in the rear end was vibrating (chattering) and popping badly when turning corners at slow speeds. Adding a bottle of the Mopar limited-slip additive completely cured the problem. I learned my lessen and now only use the Mopar additive.



Again, it can't hurt to get some opinions from professional mechanics who deal with drivelines and axles for a living.



To check the front hubs for play, jack the one side of the front suspension up at a time so the tire clears the ground, then grab the top and bottom of the tire and try to wobble it. If you feel any play, have a helper watch the suspension to see where it's coming from... either the hub or the suspension. I did this at 97,000 miles just for fun with my wife watching and discovered my ball joints were shot! One of my hub bearings showed play at 128,000 miles so I replaced them both.



Can you please describe the vibration in more detail?



John L.

 

[Parks]

Hey Don,

Just a heads up. I moved your thread to the correct forum. Hopefully this will get a little more attention.

Good Luck!

Brandon

 

[sag2]

Your going the wrong way. Shudders unloaded, add length to the center support, shudders loaded, remove length. The old TSB 03-003-04 still applies to trucks as new as 2010. All the brackets still fit.

 

[HBarlow]

Replacing weak and sagging rear springs, addition of an extra leaf, or adding lift with products like Timbrens or air bags will often cure the problem. The driveline shudder at launch frequently occurs with a heavy fifth wheel or gooseneck trailer on.

 

[outlaw1sammy]

My truck has the same symptoms you described. It shutters when taking off from a stop while turning a corner. It gets worse when the diff is hot or when there is more of a load on the truck, like taking off on a incline or backing up a hill? Keep in mind, I am empty 100% of the time and I have a short box so I do not think your problem is drive shaft or center bearing related. I have also changed U-joints. Mine seems like the diff is locked and does not release as when I turn a corner I can hear the inside tire spinning on the asphalt trying to keep up with the outside tire. I have changed the diff fluid once and did not add any limited slip additive. I thought my manual said I didn't need any? The only thing I can think of is changing the diff fluid and adding some limited slip friction modifier to see if that helps?

 

[DSorenson]

Thanks for all the great feed back!

Sunday I did put some limited slip additive in the rear end and I do think that helped and confirms some of the suggestions posted in this thread. There's a bit of history in this regard with the truck as well. When I purchased it used 4 years ago I had am oil change shop change the differential fluids and now I'm suspecting that they either didn't use a factory recommended lubricant or didn't put any limited slip additive in. I haven't driven the truck that many miles, only about 30k, and it may be just now that the problem has shown up.

So, I visited my friendly dealer today and purchase the recommended gear lube and some gaskets and this weekend I'm going to flush both the front and rear differentials. I nearly went into cardiac arrest when the part clerk told me the price for the gear lube, $25 / Qt!!!! Ouch! That's $150 for the 6 quarts needed to do both units. If anyone has some suggestions regarding a less expensive source for this stuff I'm all ears!

I'll post again once I have some results after this weekend.

Thanks again everyone,

Don

 

[Prairie Dog]

I finally gave up on the DS and installed a 1 pc. It's one of the best mods I ever made and the truck launches very nice now.

 

[JLandry]

I nearly went into cardiac arrest when the part clerk told me the price for the gear lube, $25 / Qt!!!! Ouch! That's $150 for the 6 quarts needed to do both units. If anyone has some suggestions regarding a less expensive source for this stuff I'm all ears!

Don,



In the future, just buy whatever brand of high-quality synthetic gear oil is available in your area, but ALWAYS use the Mopar limited-slip additive. There's no need to buy your gear oil from a Dodge dealer. I'm partial to Valvoline SynPower® Full Synthetic Gear Oil because it's reasonably priced and available at a Napa store near where I work.



You can buy the Mopar limited-slip additive HERE online for only $7. 02 per bottle. The Dodge part number is 4318060AB.



Please let us know how things turn out.



Good luck,



John L.

 

[fox]

As far as the center support of the two pc. driveshaft goes, I know of one that needs it raised , not shimmed down.



This will not cause a shudder in turns only.

 

[cerberusiam]

I nearly went into cardiac arrest when the part clerk told me the price for the gear lube, $25 / Qt!!!! Ouch! That's $150 for the 6 quarts needed to do both units. If anyone has some suggestions regarding a less expensive source for this stuff I'm all ears!

Just use the Valvoline 70/90 GL-5 lube, no reason to pay that much for the same product from the dealer.



There is also no reaosn to use the limited slip additive in these diffs, there are no clutch to bind like the danas and cause problems. Normally using a good GL-5 fluid will minimize a lot of problems seen with other fluids. there is in fact a pretty good idea using the LS modifier cause the LS to quit working correctly.



A bit of a bind or shudder in a turn is pretty normal with the Torenson type diffs. The are a TQ bias LS and operate off of axle shaft speed differential. When you corner one axl speeds up and tends to activate the LS. The brake shoes on the LS start to grab and if the fluid is wrong then cause a little shudder. Whether the shudder is the diff or skifdding the tires is the question. Most of the time it is the tires skidding that cause it and thats normal.



I would use the correct fluid and check things out again before using additive.

 

[TCDiesel]

I had that launch shudder for years. . in My 03. . it was not resolved until the Diff was replaced with TrueTrac & went to the 1 piece DL. I have performed this on 3 trucks problem was not cured until both the Diff & DL were replaced. I hope it would as easy as DL replacement ,but like in most cases it was NOT. ugh. My other Dodge's (2003+) all have Launch Shudder also, this includes 1 V-10 2500 2003. None of My Dana axles have it, this includes, 1 2001-2000,2-1997s all v-10s ,1 2002 Cummins. see a pattern!!!!!

 

[DSorenson]

I went ahead and did the lube change on the rear end this afternoon using the recommended $25/Qt Mopar lubricant. After asking a few more questions at the dealer I was told that on the 11-1/2 rear end in my truck you can either use the Mopar recommended lubricant without an additive or you can use a quality synthetic and use Mopar's additive, the additive priced out at ~$25. It would probably have been less expensive to go the additive route, but I opted to use the Mopar lubricant. Anyway, drove the truck about 20 miles (10 up hill / 10 down hill at highway speeds - I live in the Colorado mountains) and depending on how heavy footed I am with a turning launch the vibration is 95% to 100% resolved. If I lay on the power I can still feel a very brief and slight twinge about midway through the turn (probably at the point of highest difference in wheel speed). I'll be pulling my 5th wheel again in a couple of weeks and it will be interesting to see how it does then.

Thanks again everyone for your commentary. For now I think I'm going to consider this case closed with the moral being "don't cheep-out on the differential oil changes"

Don

 

[TCDiesel]

The best way to see if its gone for good, Pull something 50 miles or more without stopping at 65 MPH or more,exit off Freeway turn sharp left or Right,If it does Not occur on the 1st turn its gone for good.

 

[Prairie Dog]

After installing a one I suspect suspect a fluid dampener would help a lot of trucks with this issue ~ especially if the engine has even minor mods like mine does.

 

[sag2]

After asking a few more questions at the dealer I was told that on the 11-1/2 rear end in my truck you can either use the Mopar recommended lubricant without an additive or you can use a quality synthetic and use Mopar's additive, the additive priced out at ~$25.



Don

I hate to tell you your dealer does not know what he is talking about, but your axle, and every other HD American axle does not use a limited slip additive. There are even bulletins warning them not to use additive in American Axles.

If you look at the design (I have some photos of the internals posted) it has no clutches that the additive would affect.

 

[MelvinPierce]

Mine shuttered bad with a heavy load it I tried to accelerate much at all, like at a light. Went to the one piece driveshaft, problem cured.

MP