Big Time shudder at low speed/low pedal

[hemihead2]

All-
My PW just developed a significant and Intermittnet low speed shudder in the drive train that is most pronounced when the truck is under light throttle and shifts to a higher gear (i.e. 1-2). As soon as I give it gas it seems to go away but returns once again at low throttle. The 4wd shifter lever shudders significantly when the condition is present. I have a Superchips programmer which showed nothing on the diagnostics (no fault code). I disconnected the battery and then reprogrammed the truck with no improvment. The condition is not effected by vehicle speed, cruising in neutral or in 4wd. My hunch is that I developed a low speed miss that goes away when I hit the throttle....could it be a TPS? Any help is appreciated! Thank you.

[HeavyDuty]

Sounds like something in the MDS system to me. When you give it more gas it cuts the mds off and gives you all cylinders again.

[DamageWagon]

What year is your truck? Sounds more like a transmissionproblem. Several guys have reported weird trans issues due to a bad solenoid.

[waldo]

What year? I just had the EGR valve replaced on my 16. MDS should throw a check engine if it's wonky.

[olyelr]

You are not alone. Take a few minutes and read through this thread...


http://forum.powerwagonregistry.org/vie ... it=Shudder

[olyelr]

Also, I had a trans solenoid replaced under a recall... no change, mine still does it (not quite as bad as what you describe, though).

[hemihead2]

Sorry, guys I didn't give you enough info....it's a 2005 with 157k on it. Ran like a dream up until two days ago..

[hemihead2]

Also, it still does it even in tow/haul mode..

[coder]

Sounds like a bad plug or coil when was the last spark plug change?

[Retired BLM Rig]

Just speculating out loud:

• Check your U-joints, look for rust coming out of the cups. Park on level ground, set the parking brake, block the wheels and leave the transmission in neutral then feel each U-joint for play.

• When was the last time you greased the hidden fitting in the front driveshaft? (check the double-cardan center ball for play)

• When was your last trans service? Was the right fluid used? (incorrect fluid can cause a shudder).

• Low trans fluid or a dirty filter can cause shudder.

• If it was a misfire the computer should set a P0300 - P0308 code.

• If it was the TPS it should set a code and show faulty data on a scanner

• A test drive with a reputable mechanic may result in a free diagnosis and estimate. (most good shops will do this)

• It sounds like a seat of the pants kind of sensation that an experienced technicians butt should recognize.

Keep us posted.

[hemihead2]

Wow! Thank you for the good info, I appreciate your interest in my dilemma.

To update-: I checked the fluid and it was down a full quart and a half. Initially, it seemed to cure 90% of the shudder but after I let it cool down and drove the truck cold the symptoms returned. I think I can more specifically ID the issue happening at between 30-40 mph with about 5-10% throttle...the whole cab shakes enough to start squeaking audibly...until I either let off the throttle or give it more gas, then it stops.

So- no engine codes, I have changed the plugs, and tranny fluid/filter within the last 10-20k miles. Using ATF+4 Syn, all joints have been replaced over the same time span. Double joint greased probably 10k ago after it was replaced. Ball joints are probably due though.

My issue is that I can identify exactly when it began. I was making a tight right hand turn onto a divided highway and only moderately accelerating when the shudder began. I thought I had a flat at first..the fact that the 4wd shifter handle goes nuts when it's happening makes me think it's a tranny issue..

[Retired BLM Rig]

Make sure you check the trans fluid level when the truck is idling in neutral to obtain a correct reading. Mopar trannies are different than others that are checked in park idling.

[DamageWagon]

My 2011 has he same 545RFE trans as yours, maybe different controls. I don’t know what has caused it but the 3-4 shift in my trans is now an odd process. The truck will start the shift and drop rpm some, then go back to the previous gear rpm, then drop rpm again and then complete the shift. Like it’s dragging the clutch, letting off, dragging again and then it works. It is dead on consistent every time and occurs worse at lighter throttle and I don’t know that I notice it if I am hard on throttle.

It sounds like you might be feeling affects during the same gear change based on the speed your problem is in. I wonder if our clutch packs are going or if there is something going on in the valve body?

[hemihead2]

UPDATE- I checked all the universals and they look OK- I have replaced them all within the last couple years...it now seems like the issue is more defined in second and third gear. Does that change or influence anyone's opinion?

[hemihead2]

Today I had a trusted Tranny guy drive the truck and he insists that it is a bad universal in the rear drive shaft that is causing my vibration. I guess that's a cheaper fix but if true it makes me mad because I changed them out once already about 15k miles ago. I visually inspected the joints and I don't see a problem but I guess I'll change them anyway. The problem is definitely worsening.

[DamageWagon]

If you want to test it you can pull the driveshaft and stuff a coke can or febreeze can in the hole and test it in front wheel drive. If it’s your u-joints you will see the problem when you disassemble them, but probably not until they’re already out and the new parts are going in anyways when you’re at that point.

[waldo]

My issue is that I can identify exactly when it began. I was making a tight right hand turn onto a divided highway and only moderately accelerating when the shudder began. I thought I had a flat at first..the fact that the 4wd shifter handle goes nuts when it's happening makes me think it's a tranny issue..

Has that truck ever had the diff removed and the locker actuator replaced? Reason I'm asking is that they are very sensitive to the amount of bearing preload when reinstalled. They will shudder in tight turns if not set up correctly.

[hemihead2]

The rear has never been serviced. I had the the front diff rebuilt because of a bad pinion bearing a couple years ago.

Will a bad u-joint be detectable by simply jacking up the rear wheels and spinning the driveshaft in neutral?

[olyelr]

The rear has never been serviced. I had the the front diff rebuilt because of a bad pinion bearing a couple years ago.

Will a bad u-joint be detectable by simply jacking up the rear wheels and spinning the driveshaft in neutral?

No. Not necessarily, unless it is completely shot. Take the shaft off and take a closer look. Sometimes you cant tell until you actually start removing it.

[Bill2014]

There is a signature two-tone squeak that the universal joints often make when they are going bad. It is most audible when you first take off - and progressively gets faster as you speed up. Do you remember hearing this universal joint squeak?

[hemihead2]

No squeaks so far. I did take another master mechanic for a ride today and he was shocked that he could feel the vibration in the passenger's seat and even more so when I let off the gas it nearly went away in an instant...needless to say, I scheduled some rack time next Friday. We are going to pull the rear drive shaft and see what's up with the u-joints..

[hemihead2]

And the dance continues....finally got the truck on the lift today. It definitely needs new upper ball joints, but the rear driveshaft universals were fine. In fact, all the universals looked good...the issue seems to have worsened from last week and NOW when I put it in 4wd (going straight at any speed) the vibration lessens but still remains...it is becoming worse at 20-30 mph under load but if I drop it in neutral at any speed it darn near goes away..has anyone ever had their Transfer case go out? That's my current suspicion...

[olyelr]

Hows the cardon joint in the front shaft?

[DamageWagon]

That’s an odd circumstance. You might pull your front driveshaft and see if that helps. The front driveshafts lose their cardan on these trucks, and when those go it gets really expensive. My truck lost the cardan and it took out the driveshaft, blew the transfer case, dented the underside of the cab and almost wiped out the huge wiring harness and transmission wires next to it. JeepnJohnny lost his cardan a few months ago and lost the case plus wiring harness. Some trucks snag the fuel line.

That’s not to say it’s your driveshaft st fault, but it’s easy to pull the front shaft and take that off the list. The case can also be going out. Based on the gear/load description it sounds much more like transmission. You said the shutter mostly goes away if put in neutral, so there is some still occurring in neutral?

[hemihead2]

So I took another tranny guy for a ride and he really thinks it's the front drive shaft. Im in the process of pulling it but the. problem is one of the T40 bolts to the front axle flange is stripped....my luck isn't the best lately. Anyone have any ideas how to get it out? It was really on there tight before it stripped...I even heated it up with a torch and PB blaster!