Vibration under decel

[derck_mullin]

All,

Recently (within the last couple of days) my truck has started to vibrate when decelerating (shakes the truck, but not the steering wheel). Speed range is from about 35-15 mph. I put the truck into neutral and did the same test and got the same results. Does it while braking or just slowing on its own. Over the winter it seemed like the truck started behaving weird. Basically its a rubbing type feeling when around the same speed and turning the wheel just enough to get out of the dead on center spot (hope that made sense). This has been occuring for about a month. Didn't quite find what I was looking for on a search, so hoping someone can point me in the right direction.

Thanks,

Derck

[Jarrod B]

put the truck in neutral, set the pbrake. get under the truck and shake that drive shaft in the middle. if theres a lot of play, the carriage bearings might be out.


have you had the tires balanced?

[derck_mullin]

Jarrod,

Thanks and I'll try the driveshaft.

Doubt its the tires. No high speed vibe on the interstate and no shaking in the steering wheel. The tires are like new but I don't know when they were balanced previously.

Anything else to look at?

Thanks!

Derck

[derck_mullin]

Well I got under the truck. I'm not sure I was doing the right thing now that I re-read your post. The hanger that the driveshaft sits in is pretty well shot and the driveshaft moves up and down and side to side quite a bit, but that isn't a bearing of any sort. Was I supposed to try fore-aft movement? If so there really wasn't any play.

Also, I now remember I bumped a curb on a turn pretty good with the left rear while making a turn. Tonight, I shook the top of all the wheels while the truck was sitting there and could have sworn I felt a small wiggle from that left rear wheel...maybe just imagining it.

Otherwise everything looked pretty good. Most of the bushing looked ok and I was able to freely spin the shafts on the front, so they aren't engaged.

Guess I'll have to keep looking...

[Quickhorse]

Take the whole rear drive shaft down and get new ujoints and new carrier bearing. The thing holding the driveshaft up in the middle is the carrier bearing. Definitely worth it to have the rear driveshaft balanced but not the front on 4x4's.

[derck_mullin]

QH,

I'll do that then. I didn't think that would be a "bearing". Guess I'll have to take a look at a pic of the shaft with all of the parts labeled in an exploded view. I'm thinking that is probably a lot of the problem...I'll replace when I get home and see how it does.

Thanks!

[applianceman]

how did you make out with your vibration? My 02 just started this out of nowhere and the only thing that I can come up with is a bearing in the u-joint is about to lock up or I have lost a weight off of my drive shaft. I am starting to get baffled as I hate just replacing parts without knowing that they are bad.

[derck_mullin]

Still doing it. I've replaced the carrier bearing, all the u-joints, and had the tires balanced and rotated. I drove the truck in front wheel drive only with the rear shaft out up to the speed where it start the vibration and it was smooth. So I'm pretty sure my driveshaft is out of whack. I can't find where the weight was if that's the case but it sure seems to point to that being the problem. Unfortunately from what I've heard any of the above can cause the problems, so replacing all of the parts might be necessary. My truck has 200K and the ujoints needed replacing as did the carrier bearing and the tires needed to be balanced and rotated. So although this didn't fix the problem I figured...what the heck it was stuff that needs to be done anyway.

[jonbrummond]

I have a theory...
Please do not rule out the tires. Different tires can and will vibrate at different speeds. Since the occurance is so closely linked to a speed parameter, I'll bet it is your gremlin. For example, the 36" Nitto Terra Grapplers consistently vibrate when traveling through the 56-61mph range. I first thought they only did it during deceleration also. However, after accelerating down a steep hill without my foot in the throttle I also heard and felt it. It is much more difficult to appreciate the sound and feel of it under engine throttle and noise. When I swapped out to a different tire, the vibration resolved. When I went back to new Terra Grapplers, it returned.
I hope this helps.
Respectfully submitted,
Jon

[derck_mullin]

Jon,

I don't think it's the tires since it didn't vibtrate at all when I took the driveshaft out and took it up to the same speed. Funny tho the tires are the Nitto's. Also I had the tires balanced on the big Hunter so that will tell you if the tires are bad (or so they claim).

Derck