85 300TDT 270k

I have been noticing a vibration that occurs most noticeable at ~65mph. I am not sure what it feels like when the rubber flex peices on the drive shaft go bad could these cause a vibration...it is subtle. It could be a tire but usually I can tell the difference. Is there a specific characteristic associated with these rubber peices dry rotting/going bad?


Thanks for your time,
Alec.

Hello Everyone
A simple visual examination will confirm a bad flex disk.
Look for cracking or/and surface ripples.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

Probabaly a worn universal joint. Search for mine and Larry Bible's posts regarding driveline and drive shaft vibration. Larry had a good idea about inserting a thick washer under one side of the center support to cause the u joint to run in a slightly different path which might reduce vibes on a old shaft.

Good luck.

__________________
Never a dull moment at Berry Hill Farm.