03 cummins vibration

[searstractorfan]

Ok guys hopefully you all are smarter than the 3 mechanics ive had look at my truck.....I got the 5.9 cummins with the 6spd.....I drive the truck(doesnt matter RPM) it has a HOOORRRRRIIIIBBBBBLLLLLEEEE vibration from about 5mph to about 18mph....It had a front u joint that was out but I got that fixed(man $500 to fix it)....I thought it was the U joint but that didnt cause it.....I need help!! I was told its the rear end or transmission by one place, and another said it was the motor(haha motor runs FINE!!!).....Any thoughts?? I gotttttta get this fixed!!! The Payments keeep coming but I cant drive it....

 

[12ga diesel]

I just got done dealing with this same issue with my truck. Except the vibration I felt would get worse the faster I went. I had a front driveshaft u joint that was broke and the front axle u joints were about to break. I got all the u joints replaced up front including the front driveshaft, and still had a vibration. Talking to a friend, he said it could be the torque converter. I took it back to the dealer, had a mechanic come ride with me in the truck so he could feel and hear it. He said it was the rear u joint and sure enough, it was. Truck now runs as smooth as it ever has. So I would get the rear u joints checked out and replaced. Might be the thing that will make the difference.

 

[searstractorfan]

I had a shop look at it, and they say that the all the joints were fine BUT the one I replaced.....I cant even make them clang or nothin when trying to turn the shaft....I was told its the rear or the trans, then another place said it could be the motor...I had a "back yard" mechanic say the flywheel could be cracked or warped...Im at a loss....

 

[Cumminalong]

Is it shaking badly at idle?

If it is, then it's possibly an injector. All they need to do is hook the truck to the DRBIII and do an injector kill test to find out if it is.

It's very possible the TC and / or flexplate have cracked or seperated. Wouldn't be the first time I've seen that.

Sometimes the TC bolts will back out and the TC wobbles and ends up cracking the flex plate and taking out the trans pump bushing.

If it was me, I'd be starting there.

 

[searstractorfan]

Its a 6spd stick so torque converter cant be lose......It shakes the whole truck only at 5-about 18mph...doesnt matter about rpm on engine or choice of gear..Or if its i gear, out of gear, on the brakes or off......and no shakes at idle while not moving..engine is the best part of the truck!!!

 

[BudTX]

Its a 6spd stick so torque converter cant be lose......It shakes the whole truck only at 5-about 18mph...doesnt matter about rpm on engine or choice of gear..Or if its i gear, out of gear, on the brakes or off......and no shakes at idle while not moving..engine is the best part of the truck!!!

It has to be in the driveline. This sure sounds like a u-joint, but I have to ask if all of your wheel lug nuts are tightened, and if your tires are all balanced.

 

[searstractorfan]

they are tight!!! first thing i checked was them!!!! Ok good news!! I think its the support bearing on the drive shaft!! I took a jack and raised the rear end and put it in gear(2nd which brought me to a steady 5mph) and spun the rear end...It started the vibration....My uncle happen to watch the drive shaft and saw it wobble, he said its wobbling around in that bearing.....So can this be my problem?? or is the shaft grossly out of ballance? or bent?(weights are still on the shaft I looked for shiny spots of missing item, and their are none....tires should be balanced havent touched them and it just started randomly doing this vibration then it has kept persisting to do it now, so maybe that is the cause the bearing is toast!!! any thoughts?

 

[Cumminalong]

I didn't even read that in your sig that you have a 6 spd long bed.

Check that center carrier bearing.

With that many miles, that thing is probably shot and causeing all your problems.

 

[Cumminalong]

This is the part that is the #1 cause of vibrations in trucks with the 2-piece driveshaft.

We see EASILY 2 out of 3 trucks that come into the shop and have over 70K miles on them have a problem with this carrier bearing.

That's why we have this....

Unfortunately, we don't have them for trucks with the NV5600, so you're kinda stuck replacing the carrier bearing.

 

[searstractorfan]

Dang, mines got 123xxx miles so its prolly WAY over due....when you gonna build that for the NV5600??? thats a smart way to fix that problem!! and cheaper on u joint repairs too!!! I sent you a pm cumminalong, ill get back with ya today sometime prolly...

 

[searstractorfan]

Got the problem fixed, it was a u joint starting to stick beind the carrier bearing!! Thanks for all the help guys!!