87 300TD pulse in drive train ?
 

Hi all,
I have a 1987 300TD, 189k. When driving after sitting(cold) I am getting a pulse out of the drive train. I think about three of four before I get up to 20mph+/- It is a very obvious and then goes away. After driving and stopping for a short time it does not happen. The car has to sit for a while about 4 hours and the pulse will return. I had a transmition service and leaks fixed not long ago. My rear pinion seal is leaking, but fluid is up. Any thoughts are greatly appriciated. Thanks