Shaking Between 45 And 55

[echosider]

Greetings all. I have a 2003 Sierra 2500 HD 6 liter auto. When I'm driving I get a horrible shaking between 45 and 55 mph. Seems like it's in the tranny or transfer case. I am getting some leaking between the tranny and transfer case. I tried to search for similar problems but found little. Any Ideas?

 

I did find one similiar problem with U-joints when using different search terms, but I'll still take any other input that might be out there. Thanks!!

[SWDoodle]

Greetings all. I have a 2003 Sierra 2500 HD 6 liter auto. When I'm driving I get a horrible shaking between 45 and 55 mph. Seems like it's in the tranny or transfer case. I am getting some leaking between the tranny and transfer case. I tried to search for similar problems but found little. Any Ideas?

 

I did find one similiar problem with U-joints when using different search terms, but I'll still take any other input that might be out there. Thanks!!

 

 

Sounds like the driveline (u joints) to me. I'd get under there and check it out to see how much play there is. Not something to mess around with.

[importkiller76]

Yup had this problem on a 94 sierra once. Went through 3 trannys before I realized what was going on. Kept having a wicked shake between certain speeds and would stay there until it would crack the casing for the tranny. I ended up being a simple worn ujoint!