Vibration issue - please HELP!

[CS888]

Hello everyone,

To begin, I have an 85 4x4 Pickup Xtra Cab. 22R; 5 speed manual; approx 263,000 miles on the clock. I purchased this truck about 2 months ago, and have been trying to solve a persistant vibration I get upon acceleration.

If I accelerate very lightly it gets up to speed without little or no vibration, but if I give it gas at any point, at any speed there is a vibration that seems to begin in the front, and travel to the back (that's the best way I can describe it).

Here is what I've done so far:

Replace the motor mounts (Toyota parts).
Replace the tranny mount (Toyota part).
Replace the three u-joints on the rear driveshaft, and the center support bearing (NAPA parts).
Checked that the exhaust is not touching any part of the body.
Replaced the clutch and all associated parts (Toyota parts) and machined the flywheel.
Replaced all fluids (except the brake and clutch fluid).
Changed spark plugs; air cleaner; cleaned carb.

Any ideas or suggestions would be appreciated....this is driving me crazy!

Chris

 

[nat88toy]

i just got over a vibration problem thanks to the guys here turned out to be the t-case mount to bad you already replaced that

-could be your tires, missing any weights
-check to see if your drive shaft is missing a weight
-make sure the front wheel bearings are all torqued to spec
-check to make sure your tires are properly aligned

only thing that sucks about getting a new to you truck is working out all the bugs! good luck keep us posted

 

[WarDamnEagle]

I'm assuming that you are driving in 2WD so that would rule out the front driveshaft.

Although you replaced the u-joints, I wouldn't rule out an unbalanced rear driveshaft. I had this problem on a Suburban and after trying everything it turned out to be an unbalanced driveshaft. I also remember that it was very, very difficult to tell where the vibration was coming from.

 

[Texx]

Did you have the ujoints professionally installed by a driveline shop or beat em in yourself? I'd look for looseness in the rear pinion, along with pulling the driveshaft and having it spun in a driveline shop.

 

[Anthony1]

I'm having the same problem but I chased it down to loose rear t-case output flange. You might want to take the d-shaft out and put the truck in 4wd and in gear..then hammer out the crush collar nut...see if you can toque the nut down more to 90 ft/lbs. If yes, then get an new nut from the dealer and tighten that to 90 ft/lbs. If there's a leak there, you might want to replace the seal while you're at it.