I have a Discovery II 1999 with 105,100 miles few months ago I began noticing a strong vibration when I and driving between 25 to close to 40 miles per hours after that truck rum smoothly
Any idea what may be happening
Thanks

 

have you ever check you drive shaft?

 

To put a finer point on it, the front drive shaft. The oem one has some sealed u-joints. When they dry out, it will vibrate and can split without warning, knocking a hole in transmission. That will cost on the order of $7,000 for the dealer to replace. The shaft can be rebuilt for under $100 in parts (in our tech area), or replaced with an upgraded after market shaft by a DIY owner. Grease every oil change.

 

Than you for yous answers,
I did have to change the drive shaft around 20,000 miles or 3 years ago because broke and one end just fall in that pavement -the other end remained attached to the truck- I will have it check to verify that sealed u-joints has not dry out.

 

There is also a rubber coupling at rear differential that sometims cracks.