I am in the middle of a very long trip. I am driving back to CA from Cancun, Mexico. I am stuck in Kerrville, TX.

My truck has a very nasty vibration coming up the stick shift and floorboard. This happens at 50-60mph with it being very bad at 55mph. It settles down at about 65mph. I went to a mechanic I and he and changed the carrier bearing. The vibration is still there. He said the U-joints all looked good. We called it a day.
He wants to check all the differential and transmission fluids tomorrow.


We called it a day and I will return tomorrow.

What else should we look at?

 

It probably lost a weight off the driveshaft, or one of the rear tires is separated.

 

Tires were my first thought a week ago when this first happened. Yesterday I had a blowout on a highway in Mexico at 65mph. The rear end of the truck was swerving all over the road and almost flipped the truck and camper. When I finnally got the truck stop there was nothing left of the tire. I nearly sh-t myself. The second tire blew up today around San Antonio but was not as bad as yesterday.

When I had the carrier bearing replaced I also bought 2 new tires for the rear. The one in front are almost new. The shop checked them out and said they were OK.

Would the missing weights cause the vibration to occur at specific speeds?

 

Yes, wheel weights and drive shaft weights can cause vibration at certain speeds. What direction does the vibration seem to move in? Is it in the steering wheel or just the transmission?

 

Just the tranny. What do you mean when you say "direction"?

I am pretty sure it is not the tires

 

I'm not sure how the carrier bearing bracket is attached to the frame on your truck but I had one once that wore the bolt holes out on the frame and it caused the whole bearing and brace to vibrate which nobody I took it to thought about.

It took me 3 drive shafts and a dozen u joints to finally tell one guy to start at the rear end and just take everything off the truck, including the transmission if he had to, before they found it. Everyone just checked yokes, u joints and the bearing itself and never found the problem.

 

I just made it to CA and finished with this trip from hell. Most of my problems were not truck related, just a couple of blowouts and my camper hitch breaking.

I still had the vibration after I changed the carrier bearing. I just kept it below 50 or above 60mph. Everything looks good and tight including the u-joints. Now that I have the time I would like some advice on where to start looking.

 

I still haven't found what is causing the vibration. My mechanic here in CA has gone over it and thinks it might be the flywheel. Could that cause the vibrations I have at certain speeds?
He also suggested that I take the truck to drive line shop just to make sure that it isn't the drive shaft before we go any further.

When looking for flywheel he couldn't find anybody with a DMF only SMF's. I read up on the differences here but it seems that I won't have a choice. Where can I get a DMF and clutch kit if I decide to go that route?

Thanks

 

I took my truck to the mechanic here in CA and he isn't certain of the cause. When we shut the truck down he hear a major clunking sound. He thinks the flywheel is bad and that might be causing the vibration. Would that cause the vibration I get a certain speeds?

When he looked for a replacement flywheel he was only able to find a SMF. Nobody make a DMF anymore. The SMF and clutch kits are about $700 plus labor. Is there anyplace to get a DMF and what should it cost me?

He also suggested that before we start messing with the flywheel, that I take it to a driveline shop and have them check the drive shaft.

What do you guys think?
Thanks.

 

RockAuto has DMF's, but they aren't cheap...

I'm not sure if a flywheel can cause vibrations at certain speeds or so. A driveshaft definitely will though.

 

Finally found out what was causing the vibration and got it fixed. I learned something new today. Even though I had 2 different competent mechanics tell me my u-joint were good and tight they were both wrong. I took the truck to a drive line shop and they pulled the driveshafts and found that all the u-joints were toast. They told me one was crumbled into dust when they pulled it off. My drive shaft also was not balanced. They told me that the only way to really check the u-joints is to take everything apart and inspect them. Just because they feel tight doesn't mean they are good.

Now she rides smooth as silk, at least as smooth as she can be when empty.