Transmission shudder at takeoff, 2004 48RE

[RVTRKN]

I try to avoid Hsmartash these days, he's just a ash, so I hate to respond, knowing the thread will be turned upside down. sag2, HB wore out his springs under continuously overloading the the rear axles by his own admission bragging about hauling construction trailer silo's, that still had product in them from time to time between heavy RV's deliveries. This kind of duty cycle will wear your suspension components and can be expected. The way I read that TSB, was describing a cure by repositioning the angle of the U-joints, not that the Gen III springs are weak. All makes of the 1ton regular trucks have sacrificed ride over ability, due to customers complaining about the ride. Imagine that, truck buyers complaining that the truck doesn't ride like a Cadillac. The Dodge 3500 C&C rear springs are considerably stronger than the regular 3500 pickups, by design, knowing that the duty cycle is more than the regular pickup. My 04. 5 has/had the axle wrap from time to time and a one piece drive shaft was discussed by my tech at one point. But it's frequency was minimal and many TDR members described the same issue, so I just ignored it, thinking its a design flaw by Dodge.

 

[HBarlow]

More useless comments from a poser with less experience, less knowledge, fewer miles driven in any Ram, less towing, and fewer brain cells than most TDR members. A guy who is dumb enough to let a dealer tech talk him into paying for "fuel injector cleaning. "

Have you had your dealer clean your muffler yet?

 

[RVTRKN]

See, he always digresses to name calling when proven wrong. Hey, when you ride that wannabe Harley by my house on the west coast, look for the HB salute.

 

[HBarlow]

Poser, the thread was discussing trucks and truck problems until prairiedunce and then you showed up with no knowledge or experience to contribute. His and your only contribution was to insult me.

And then, like the whining poser you are, you claim inspite of your lack of knowledge and after reading proof provided by sag you proclaim me wrong and accuse me of calling you names.

Go back and read the posts.

 

[NIsaacs]

U-joint angles change depending upon the amount of weight applied to the vehicle bed,

therefore u-joint angle readings may need to be taken with different vehicle loads in order

to obtain a satisfactory compromise. The vehicle should be evaluated under the loaded

condition that produces the objectionable disturbance.

PARTS REQUIRED:

Qty. Part No. Description

AR 52105717AB Bracket - 14. 7 mm

AR 52105587AB Bracket - 19. 8 mm

AR 52105716AB Bracket - 84. 6 mm

AR 52105583AB Bracket - 89. 8 mm

AR 52105714AB Bracket - 113. 1 mm

NUMBER: 03-003-04

GROUP: Differential & Drive

Line

DATE: June 15, 2004

Qty. Part No. Description

AR 52105584AB Bracket - 115. 3 mm

AR 52105715AB Bracket - 132. 0 mm

AR 52105559AB Bracket - 133. 9 mm

I don't agree with this TSB and never have. It is a bandaid, guess and by golly, I hope if I change enough brackets, I might see an improvement. Look at all the sizes, thats crazy! There is no way that Dodge mounted the engine, transmission and front (short) drive shaft any different between trucks. They are mounted in the frame rails the same, thats a given. The problem is, some Monday morning hungover tech welded the spring perch on the rear axle slightly off, causing the pinion angle to not match the engine crankshaft center line. The rear drive shaft/u-joint angle changes with or without a load, thats not the problem. If the pinion angle is off, then depending on if the load is on the bumper or in the bed, this angle can get worse, thats the problem. Thats why the factory front to rear built in rake needs to be there, don't mess with it. I am talking about a new truck. If the truck is older, then all bets are off, there are too many variables now.



The single most common cause of drive shaft shudder in an otherwise stock built truck, is a bad u-joint or in the case of a two piece, a bad u-joint or center bearing or cushion. This is assuming the pinion angle is correct.



Nick

 

[RVTRKN]

Gen III trucks used frequently for heavy towing are known to shudder on launch because the rear leaf springs are weak and sag under load with age. Adding a leaf to the rear springs, adding Timbrens, or installing air bags will often cure it.

Weak springs as you stated are not the cause, it's alignment that the TSB sag2 posted.

 

[RustyJC]

I've seen launch shudder under some conditions on every dually Ram I've owned when towing heavy 5th wheels, some more severe than others. There's a significant change in pinion angle between unloaded and towing conditions as the rear suspension sags, and under heavy torque loading when towing, the launch shudder will show up. I'm sure that airbags would help by minimizing the sag and, thus, the change in pinion angle, but (knock on wood) I've never had any driveline failures. In the configuration the trucks are built, I've always just considered mild launch shudder as part of the nature of the beast.



Rusty

 

[cerberusiam]

U-joint angles change depending upon the amount of weight applied to the vehicle bed,

therefore u-joint angle readings may need to be taken with different vehicle loads in order

to obtain a satisfactory compromise.

That pretty much says it all, its a bandaid compromise. It works on some trucks, not on others because there are simnply too many variables to address.



Pinion angles are not meant to be static. The whole drive line is engineered to work smoothly thru a range of angles. As long as that geomety is maintained no amont angle changing, shimming, or air bags is going to change how it works. Typically lost in al the discussion is the fact that as the suspension is loaded the drive line geometry gets BETTER not WORSE. There is also much less movement of the pinion becuae as the suspension compresses it becomess stiffer increasin the force needed to deflect it.



Then why is launch shudder more prevalent under load than empty? Kinda blows HB and his theorries right out of the water. Poof! Gone in a puff of smoke. :-laf



Launch shudder is used to describe every little wiggle and vibration that is felt when the loud pedal is applied. Trying to diagnose if it torsional harmonics or drive line deflection is a thankless task. The most common cause is stll a rapid occilation of the driveline geometry due to TQ input. Whether it is the center bearing deflecting and returning, a dry u-joint causing a bind, or just the pinion angle radidly changing it is still the same root problem, massive amounts of TQ applied to large weights thru a variable geometry transmission point.



If you reduce the TQ rise or smooth out the application 99% of the time the problem disappears. Whether it is the training of the right foot or parts replacement\additions that addresses the root issue, it works.

 

[HBarlow]

That pretty much says it all, its a bandaid compromise. It works on some trucks, not on others because there are simnply too many variables to address.

Pinion angles are not meant to be static. The whole drive line is engineered to work smoothly thru a range of angles. As long as that geomety is maintained no amont angle changing, shimming, or air bags is going to change how it works. Typically lost in al the discussion is the fact that as the suspension is loaded the drive line geometry gets BETTER not WORSE. There is also much less movement of the pinion becuae as the suspension compresses it becomess stiffer increasin the force needed to deflect it.

Then why is launch shudder more prevalent under load than empty? Kinda blows HB and his theorries right out of the water. Poof! Gone in a puff of smoke. :-laf

Launch shudder is used to describe every little wiggle and vibration that is felt when the loud pedal is applied. Trying to diagnose if it torsional harmonics or drive line deflection is a thankless task. The most common cause is stll a rapid occilation of the driveline geometry due to TQ input. Whether it is the center bearing deflecting and returning, a dry u-joint causing a bind, or just the pinion angle radidly changing it is still the same root problem, massive amounts of TQ applied to large weights thru a variable geometry transmission point.

If you reduce the TQ rise or smooth out the application 99% of the time the problem disappears. Whether it is the training of the right foot or parts replacement\additions that addresses the root issue, it works.

If you continue throwing all these comments up against the wall long enough perhaps eventually something will stick. You may convince yourself and a couple of your lap dogs here but those of us who have been around heavy RV trailers for a long time know better and will continue to reject your position.

According to sag Dodge engineers have studied the problem and produced a technical service bulletin and list of parts to rectify it. Perhaps you were removing a transmission from some old lady's Buick that day and didn't answer the phone call when the Ram engineers called to discuss the problem with you?

 

[HBarlow]

I don't agree with this TSB and never have. It is a bandaid, guess and by golly, I hope if I change enough brackets, I might see an improvement. Look at all the sizes, thats crazy! There is no way that Dodge mounted the engine, transmission and front (short) drive shaft any different between trucks. They are mounted in the frame rails the same, thats a given. The problem is, some Monday morning hungover tech welded the spring perch on the rear axle slightly off, causing the pinion angle to not match the engine crankshaft center line. The rear drive shaft/u-joint angle changes with or without a load, thats not the problem. If the pinion angle is off, then depending on if the load is on the bumper or in the bed, this angle can get worse, thats the problem. Thats why the factory front to rear built in rake needs to be there, don't mess with it. I am talking about a new truck. If the truck is older, then all bets are off, there are too many variables now.

The single most common cause of drive shaft shudder in an otherwise stock built truck, is a bad u-joint or in the case of a two piece, a bad u-joint or center bearing or cushion. This is assuming the pinion angle is correct.

Nick

Nick,

Have you owned a Gen III dually?

 

[NIsaacs]

In the configuration the trucks are built, I've always just considered mild launch shudder as part of the nature of the beast.



Rusty

Exactly, if it ain't broke don't fix it. This issue arrived with the massive low rpm torque of the Cummins. Like Cerb says, use your right foot if it bothers anyone. If there are no mechanical issues in the first place, this shudder will not hurt a thing. Most of the complaints originated from gasser drivers/owners with their first Cummins.



Nick

 

[RustyJC]

Most of the complaints originated from gasser drivers/owners with their first Cummins.

Cummins not required. My 1996 3500 with V10/47RE would shudder on takeoff when towing our 5th wheel with the application of heavier torque.



Rusty

 

[NIsaacs]

Nick,



Have you owned a Gen III dually?

Harvey,



No I have not. I have avoided the spring discussion for obvious reasons and pointed out that the pinion angle is more important than the rear drive shaft/u-joint angle. This pinion angle on a used truck can change for a variety of reasons... . hint... hint



Nick

 

[JJPage]

Just a couple of thoughts, could the shudder the op is experiencing be caused by a loosening flex plate at 120k ?

I use Dextron III @ DTT's direction. When towing heavy, especially in stop and go traffic when my trans temp started to rise, I was getting a shudder at take off. Bill @ DTT had me add two bottles (8/10 oz each?) of a trans fluid supplement (Redline additive), that eliminated the shudder in my case.

I do not know if ATF+4 has those properties or not, but suspect they do, however a breakdown in fluid from use, could maybe contribute to this?

 

[cerberusiam]

If you continue throwing all these comments up against the wall long enough perhaps eventually something will stick. You may convince yourself and a couple of your lap dogs here but those of us who have been around heavy RV trailers for a long time know better and will continue to reject your position.

Woof! Woof! Watch out for the lap dogs, they will bite the back of your front with little provocation. :-laf

According to sag Dodge engineers have studied the problem and produced a technical service bulletin and list of parts to rectify it. Perhaps you were removing a transmission from some old lady's Buick that day and didn't answer the phone call when the Ram engineers called to discuss the problem with you?

Where did you hear that? The internet? Everything on the internet HAS to be true of course. Oo.



Like a Cummins diesel is the ONLY truck to ever suffer launch shudder, like a RV hauler is the ONLY one to ever see this. LMAO!! You are such a poser when it comes to anything other than sitting behind the wheel. Most of us have spent more time under the truck rectifying Mother Chryslers inventive engineering than you have spent behind the wheel. Bounce off into the sunset with your air bags. Swagger Jacker!!!

 

[JR]

Just a couple of thoughts, could the shudder the op is experiencing be caused by a loosening flex plate at 120k ?



I use Dextron III @ DTT's direction. When towing heavy, especially in stop and go traffic when my trans temp started to rise, I was getting a shudder at take off. Bill @ DTT had me add two bottles (8/10 oz each?) of a trans fluid supplement (Redline additive), that eliminated the shudder in my case.



I do not know if ATF+4 has those properties or not, but suspect they do, however a breakdown in fluid from use, could maybe contribute to this?

I also use dexron at the advice of my builder. He never got into detail but from my understanding its simply because the clutches dont need the added lubrication of synthetic and although it wouldnt hurt the trans, theres no sense in using the more expensive +4. My trans is not a big name company but through a local guy that is well known in the tri state area for building bullet prrof pulling transmissions capable of withstanding gobs of driveshaft twisting torque Whatever the reason, the change in fluid has worked well for me at this point.

 

[rscurtis]

Launch shudder will tend to occur when the U-joints end up not working at complementary angles. Let's say that the front and rear u-joint are at 2,5* for the sake of argument. As the rear axle is loaded, it will tend to upset that angle, possibly going over to 2. 5* in the other direction, for a total change of 5*. Meanwhile, the front u-joint has hardly seen its angle change at all. Once the speed is increased and the load reduced, the shudder goes away. I had both a 1980 and 1988 Ford E350's that were used for towing, and launch shudder was common, even on the 1980 with its gutless 400 "Cleveland" engine.



The reaction you feel in the steering wheel of a 4X4 when turning sharply is launch shudder greatly exaggerated.

 

[cerberusiam]

As the rear axle is loaded, it will tend to upset that angle, possibly going over to 2. 5* in the other direction, for a total change of 5*.

It won't though, within the load ratings. At full compression the angle on both front and rear joints should decrease. The pinion angle and t-case\trans angle both decrease but stay within acceptable ranges thereby reducing the chance of launch shudder. After all, the closer the angles the less the stress is to deflect and cause shudder.

What frequently happens is the ujoints wear in running in an unloaded position. Then when the angles change due to load there is a slight bind as the cross is not out of its normal range. This bind sets up the ocillations as pinion angle as goes over the bind center point.

 

[BIGNASTY]

Barlow as the VA shrink said SEEK HELP you need a padded room and some time drying out. Seriously Harvey you need some help I know because ive been where your at not with alcohol that I imagine that you abuse but with prescription drugs, TAKE IT FROM A EX ADDICT HARVEY SEEK HELP the VA have counselors that can help you get thru this. If not because of drinking and that DT's but can also help with mental illness

http://www.mentalhealth.va.gov/VAMentalHealthGroup.asp

Here is a list of facilities in Texas find one and check in
http://www2.va.gov/directory/guide/state.asp?State=TX&dnum=ALL

Harvey Sincerely get some care
BIG

 

[goodguys75]

Just got back from Yosemite. Nice trip, warmest I have ever been there at about 65 degrees. Had a slight issue with the trans and want to know what you guys think. I had been on the road for about 6 hours, towing 10k with the signature truck with a stock 48RE. We were in the hills at about 5,000 feet elevation. From a stop, starting up a slight grade, was in low 1 or 2, 55 degrees outside and the trans was at 140 degrees measured in the pan. The trans shuddered about 3 times, a couple seconds apart. I really don't think it was a gear shift but maybe??? This was about 5-10 mph. It was the only time I have experienced this and it didn't happen again the rest of the trip.

I have not replaced the gov solenoid or pressure transducer/thingymabob but that is on my to do list.

I change the trans fluid every 30 K. About 15 quarts +/- of ATF $4. Trans always runs 130 to 160 degrees, rarely hotter.

Truck has 120,000 miles.

thanks,

Tom

Trans always runs 130 to 160 degrees, rarely hotter... ... ... ... ... ... ... ... ... ... ... . nothing wrong if the trans getts any hotter, mine runs 190-200 a lot of the times... ... and it is still safe..... are you sure it is not hunting between the 1-2 gear at a low speed take off... very common on this transmission...