Engine/Transmission (1998.5 - 2002) Truck floor vibrating at 75-80ish

[cmckinney]

Well I have balanced the tires and rotated them but still have an annoying vibration at 75-80MPH. Does anyone have this issue? I never noticed this before I installed the D25 coils but then again I never really drive this fast during normal use but I do however plan on driving to Colorado soon and plan on driving 75MPH most of the way.



This sucks! I hate my truck b/c of this problem.



-CM

 

[LSMITH]

Could be a driveline out of balance, bad u-joint, tire that is not round, bent wheel, there are just so many things that it could be that you will need to eliminate them one at a time. Personally? I would go after the tires first, make sure they are round and well balanced again, and check the wheels for runout. After that if it still vibrates I would pull the driveline and have it balanced. Odds are good that within these two suspects you will have found the problem.

 

[Gizmo 007]

Had a problem almost like that about 2 weeks ago. I could really feel the vibration through the floor. Ended up being that my carrier bearing was loose. Some wingnut forgot to tighten it (wonder who that could be ?). That could be one possibility. Also, you may want to make sure there aren't any weights missing off of your driveline. Ran into that one before on another truck.



If all else fails, jack up the rear of the truck, put it on jackstands, and put it in gear. See what it feels like. If you can feel the vibration, take off the rear tires and run it again. Then start tracing the vibrations from there.



Good luck,

Kris

 

[cmckinney]

Gizmo now how would I know how many weights should be on the drive line? Is there a source I can look at that would tell me this information?



Thanks



-CM

 

[Philip]

The weights are spot welded on. If you see a tack weld with no weight on it. Then it flipped one off.



Now a couple of decades ago the weights were poped into a hole. All you had to do was pop one out. Drop a small nut into it. Try to find that low speed rattle.

 

[Gizmo 007]

like philip said, there will be a broken spot weld or a shiny / discolored area. I know how frustrating these things can be. May be something simple, may not.

 

[cmckinney]

Would the track bar cause this kind of vibration?



-CM

 

[d90boy]

If your '02 doesn't have the Central Axle Disconnect, the front driveshaft is turning all the time. If you installed different springs and changed the ride height you likely affected the front driveline angle. The front driveshaft has a double cardan CV joint at the transfer case side. These type driveshafts require minimal angle at the u-joint, usually no mare than 3 or so degrees. If you have more angle you may be getting vibration from this due to the front driveshaft being out of phase, not out of balance.

 

[Gizmo 007]

I wouldn't think the trackbar would cause it, but don't quote me on that. Is the vibration fast or slow? Does it change with vehicle speed? Just trying to get a little more info so that maybe I could help a little more.

 

[cmckinney]

It is a fast vibration. It start at 75 then goes up to 80's. After high low 80's it seems not to vibrate as much. I may think it is my front drive shaft. Since I put the 2in leveling springs on the front of my truck I wonder if that has put the drive line in an angle that would cause the vibration at the U-Joint.



How do I take off the front driveshaft?



-CM

 

[Gizmo 007]

there are 4 small bolts that hold on the front and rear u-joints on (retaining straps). It's not hard at all. That could be it... Worth a shot anyway.

 

[cmckinney]

I saw two bolts that held on the front but there was nuts that held on the rear part of the axle and they look pretty inaccessible.



-CM

 

[hammersley]

What about the main U Joints??????

I had this problem last spring and had a disentigrated U-Joint - the main one right out of the transmission - tell us the condition of them?

 

[cmckinney]

Well Hammersly looks good. I was under there last night and didn't see any play in the U-Joints. But that may be the issue. I'm still trying to figure out how to take off the front driveshaft.



Hammersly did you do this on a 4x4?



-CM

 

[Gizmo 007]

use a stubby wrench to get the bolts at the x-fer case. jack up the front so you can spin the shaft. The bolts shouldn't be all that tight, mine weren't .

 

[cmckinney]

2 Off-Round tires Thank you Michillen

Well I finally solved my floor vibration issue.



I took my truck to another Discount Tire in Rockwall and had them do a more precise balance of my tires. On inspection they found that I should replace 2 of the 4 stock tires. They Discount Tire I went to had a special balancing machine that was more exact then the older type. The guys told me that if it would have been caught before 20000 miles I could get credit for the tires and have them replaced.



Anyways they balanced the tires and now the vibration is gone. It seems that the LTX A/S tires came bad from the factory.



Why didn't I see this problem from the time I bought my truck? I usually drive under 70mph hence I didn't notice the problem until I was speeding.



It looks like I can live with a little vibration around 75mph until the tires wear out and I buy new ones.



-CM