Prelude to a demise?

Everytime my trucks odo reached the 30mph mark it feels like I went thru a graveled road. it only takes seconds though. what could it be? wheel bearing, bad tires, alignment? transmission?.... TW help?
TY

125K

 

You mean speedo I presume ?

 

lol.. yes speedo I mean. tires are still ok well visually, although truck has never been aligned, ever. but this 'feel' is different.

 

Most likely u joints or center support bearing.

 

hmm sounds suspect. well, time to go down on her under there this weekend. btw the differential seal near the trans has traces of leakage I don't see any on the floor though- connected to the issue?


thanks x2

 

Could be torque converter not locking in.

 

I would check you u joints and carrier bearing as suggested, had much the same thing on my old nissan and it was the carrier bearing, and when it went the shaft vibration caused a leak in the trans output seal and casued trans to fail. Plus its easy to inspect the drive shaft.... maybe yours has the zerks to regrease too

 

I will check them as what's being mentioned here this weekend. hopefully it's an ant size issue,... hopefully