Bad vibration

[guamboyeli]

So I just got my truck running and it's always had this thing where when I go past 35mph it starts to vibrate...the vibration stays the same as I accelerate... Where should I look???... I checked the drive shaft and it's fine the universal joints are ok... Idk where to look...

[royster]

I have heard the input bearing in the transmission can cause this, but I'd still suspect u-joints. Also, check the transmission mount and see if it is loose due to deteriorating rubber.

[ragragtimetime]

rearview mirror shaking?!...i am slowly conquering this issue with the 1983 4wd (about 55mph vibration coming from center of truck...no matter what gear) it is slowly getting under control by welding broken cab mounts (all 6), changing bad brake caliper (front passenger) & swopping out drive shaft & universal joints (had an extra drive shaft). assuming no issues with tires, rims, or balancing...IF the rims are not stock (as in my case) verify they are centered on the hub by checking correct lugs are used to help center rim to truck mounting. as mentioned above verify all mounts and see if it is loose due to deteriorating rubber...ie-cab, bed, engine, leaf springs.

[LSR Mike]

Or the Balance shafts are not timed correctly in the engine...

[geezer101]

I would think if it was a balance shaft issue it would be showing it's ugly face at certain rpm ranges and not road speed. I hate mystery vibrations...:cussingblack:

[Sscorpion]

I would look at the carrier bearing under the truck for the driveline's. i had the same problem replaced it and everything was much better. Just remember this bearing does not take abuse very well.

[camoit]

Also balance all the tires.

[MIHIFISI]

Just as a side note, If the truck is lowered, make sure you are using angled lowering blocks. ( If you are using blocks at all ) Also check and make sure the blocks are tapered to the front.

[gnweb]

Check and make sure the u-joints are lined up properly, I put mine back in 1 time not paying attention and slid the back half in wrong, vibrated like hell on the freeway, redid the driveline and vibration gone

[guamboyeli]

it was just a messed up transmission mount... it was totally sperated

[geezer101]

...and it still turned out to be something relatively small. Just goes to show it's not always something major that can cause so much grief. All good now then guamboyeli?

[royster]

check the transmission mount and see if it is loose due to deteriorating rubber.
Ha! I got it right! The forum owes me a dozen donuts.

Chocolate~iced, please. I WILL share.

[MIHIFISI]

Krispy Kreme or Dunkin, Choose Wisely

[royster]

Krispy Kreme or Dunkin, Choose Wisely

Entemann's, most decidedly.

And to not TOTALLY thread-hijack: this is a reminder that rubber that is 25-30 years old likely needs replacing. This includes plastic surgery, boob implants, fuel lines, motor/transmission mounts, Kenny G...wait, forget replacing him, just eliminate THAT altogether...and windshield wiper blades.

Condoms are technically not rubber, but latex.

A bad transmission mount WILL affect the universal joints, so be sure to check those out for excessive wear. It costs roughly $30 to replace them, and it is well worth the time and money. If nothing else, grease them (if they have grease nipples).

Ohhh...grease nipples ghahhhhhhhhh

[BradMph]

it was just a messed up transmission mount... it was totally sperated

I just replaced mine about a month ago and locating it was a confusing ordeal. Though I could not beat the price of about 12 bucks delivered after I found the correct style used in the 86 MM.

Glad you located your problem, keep an eye on a possible leaky shaft seal. Vibrations usually will take out an old seal also some time down the road.