Hi guys this is my first post, im from mexico in saltillo city near to texas 250 miles south from Laredo, TX, I got a problem when im driving on the highway i feel a little vibration in the drivetrain at 100 mph it feels vibrating, Would you mind in giving me and advice? What to check? the rear end and change the fluid??
I've never used an additive in the rear end, would you recomend it?
It has 92K miles

thnks, mi car is a 97 LT1 M6
Best Regards. Polo.

 

Driveshaft most likely needs to be balanced.

 

Definitely use the additive in the rear end. The drive shaft is usually the culprit in drive train vibration in these cars.